chore: remove diagram file from repo

Use OPENROUTER_MODELS (28 curated) and _PROVIDER_MODELS from models.py
instead of the raw models.dev catalog (167 OpenRouter models). These are
hand-picked agentic models that work as agent backends.

Before: 167 models from models.dev sorted by capability score
After: 28 curated models in our recommended order

agent/models_dev.py

@@ -1,19 +1,31 @@
-"""Models.dev registry integration for provider-aware context length detection.
+"""Models.dev registry integration — primary database for providers and models.
 
-Fetches model metadata from https://models.dev/api.json — a community-maintained
-database of 3800+ models across 100+ providers, including per-provider context
-windows, pricing, and capabilities.
+Fetches from https://models.dev/api.json — a community-maintained database
+of 4000+ models across 109+ providers.  Provides:
 
-Data is cached in memory (1hr TTL) and on disk (~/.hermes/models_dev_cache.json)
-to avoid cold-start network latency.
+- **Provider metadata**: name, base URL, env vars, documentation link
+- **Model metadata**: context window, max output, cost/M tokens, capabilities
+  (reasoning, tools, vision, PDF, audio), modalities, knowledge cutoff,
+  open-weights flag, family grouping, deprecation status
+
+Data resolution order (like TypeScript OpenCode):
+  1. Bundled snapshot (ships with the package — offline-first)
+  2. Disk cache (~/.hermes/models_dev_cache.json)
+  3. Network fetch (https://models.dev/api.json)
+  4. Background refresh every 60 minutes
+
+Other modules should import the dataclasses and query functions from here
+rather than parsing the raw JSON themselves.
 """
 
+import difflib
 import json
 import logging
 import os
 import time
+from dataclasses import dataclass, field
 from pathlib import Path
-from typing import Any, Dict, Optional
+from typing import Any, Dict, List, Optional, Tuple, Union
 
 from utils import atomic_json_write
 
@@ -28,7 +40,110 @@ _MODELS_DEV_CACHE_TTL = 3600  # 1 hour in-memory
 _models_dev_cache: Dict[str, Any] = {}
 _models_dev_cache_time: float = 0
 
-# Provider ID mapping: Hermes provider names → models.dev provider IDs
+
+# ---------------------------------------------------------------------------
+# Dataclasses — rich metadata for providers and models
+# ---------------------------------------------------------------------------
+
+@dataclass
+class ModelInfo:
+    """Full metadata for a single model from models.dev."""
+
+    id: str
+    name: str
+    family: str
+    provider_id: str        # models.dev provider ID (e.g. "anthropic")
+
+    # Capabilities
+    reasoning: bool = False
+    tool_call: bool = False
+    attachment: bool = False       # supports image/file attachments (vision)
+    temperature: bool = False
+    structured_output: bool = False
+    open_weights: bool = False
+
+    # Modalities
+    input_modalities: Tuple[str, ...] = ()    # ("text", "image", "pdf", ...)
+    output_modalities: Tuple[str, ...] = ()
+
+    # Limits
+    context_window: int = 0
+    max_output: int = 0
+    max_input: Optional[int] = None
+
+    # Cost (per million tokens, USD)
+    cost_input: float = 0.0
+    cost_output: float = 0.0
+    cost_cache_read: Optional[float] = None
+    cost_cache_write: Optional[float] = None
+
+    # Metadata
+    knowledge_cutoff: str = ""
+    release_date: str = ""
+    status: str = ""          # "alpha", "beta", "deprecated", or ""
+    interleaved: Any = False  # True or {"field": "reasoning_content"}
+
+    def has_cost_data(self) -> bool:
+        return self.cost_input > 0 or self.cost_output > 0
+
+    def supports_vision(self) -> bool:
+        return self.attachment or "image" in self.input_modalities
+
+    def supports_pdf(self) -> bool:
+        return "pdf" in self.input_modalities
+
+    def supports_audio_input(self) -> bool:
+        return "audio" in self.input_modalities
+
+    def format_cost(self) -> str:
+        """Human-readable cost string, e.g. '$3.00/M in, $15.00/M out'."""
+        if not self.has_cost_data():
+            return "unknown"
+        parts = [f"${self.cost_input:.2f}/M in", f"${self.cost_output:.2f}/M out"]
+        if self.cost_cache_read is not None:
+            parts.append(f"cache read ${self.cost_cache_read:.2f}/M")
+        return ", ".join(parts)
+
+    def format_capabilities(self) -> str:
+        """Human-readable capabilities, e.g. 'reasoning, tools, vision, PDF'."""
+        caps = []
+        if self.reasoning:
+            caps.append("reasoning")
+        if self.tool_call:
+            caps.append("tools")
+        if self.supports_vision():
+            caps.append("vision")
+        if self.supports_pdf():
+            caps.append("PDF")
+        if self.supports_audio_input():
+            caps.append("audio")
+        if self.structured_output:
+            caps.append("structured output")
+        if self.open_weights:
+            caps.append("open weights")
+        return ", ".join(caps) if caps else "basic"
+
+
+@dataclass
+class ProviderInfo:
+    """Full metadata for a provider from models.dev."""
+
+    id: str                         # models.dev provider ID
+    name: str                       # display name
+    env: Tuple[str, ...]            # env var names for API key
+    api: str                        # base URL
+    doc: str = ""                   # documentation URL
+    model_count: int = 0
+
+    def has_api_url(self) -> bool:
+        return bool(self.api)
+
+
+# ---------------------------------------------------------------------------
+# Provider ID mapping: Hermes ↔ models.dev
+# ---------------------------------------------------------------------------
+
+# Hermes provider names → models.dev provider IDs
 PROVIDER_TO_MODELS_DEV: Dict[str, str] = {
     "openrouter": "openrouter",
     "anthropic": "anthropic",
@@ -44,8 +159,28 @@ PROVIDER_TO_MODELS_DEV: Dict[str, str] = {
     "opencode-go": "opencode-go",
     "kilocode": "kilo",
     "fireworks": "fireworks-ai",
+    "huggingface": "huggingface",
+    "google": "google",
+    "xai": "xai",
+    "nvidia": "nvidia",
+    "groq": "groq",
+    "mistral": "mistral",
+    "togetherai": "togetherai",
+    "perplexity": "perplexity",
+    "cohere": "cohere",
 }
 
+# Reverse mapping: models.dev → Hermes (built lazily)
+_MODELS_DEV_TO_PROVIDER: Optional[Dict[str, str]] = None
+
+
+def _get_reverse_mapping() -> Dict[str, str]:
+    """Return models.dev ID → Hermes provider ID mapping."""
+    global _MODELS_DEV_TO_PROVIDER
+    if _MODELS_DEV_TO_PROVIDER is None:
+        _MODELS_DEV_TO_PROVIDER = {v: k for k, v in PROVIDER_TO_MODELS_DEV.items()}
+    return _MODELS_DEV_TO_PROVIDER
+
 
 def _get_cache_path() -> Path:
     """Return path to disk cache file."""
@@ -170,3 +305,443 @@ def _extract_context(entry: Dict[str, Any]) -> Optional[int]:
     if isinstance(ctx, (int, float)) and ctx > 0:
         return int(ctx)
     return None
+
+
+# ---------------------------------------------------------------------------
+# Model capability metadata
+# ---------------------------------------------------------------------------
+
+
+@dataclass
+class ModelCapabilities:
+    """Structured capability metadata for a model from models.dev."""
+
+    supports_tools: bool = True
+    supports_vision: bool = False
+    supports_reasoning: bool = False
+    context_window: int = 200000
+    max_output_tokens: int = 8192
+    model_family: str = ""
+
+
+def _get_provider_models(provider: str) -> Optional[Dict[str, Any]]:
+    """Resolve a Hermes provider ID to its models dict from models.dev.
+
+    Returns the models dict or None if the provider is unknown or has no data.
+    """
+    mdev_provider_id = PROVIDER_TO_MODELS_DEV.get(provider)
+    if not mdev_provider_id:
+        return None
+
+    data = fetch_models_dev()
+    provider_data = data.get(mdev_provider_id)
+    if not isinstance(provider_data, dict):
+        return None
+
+    models = provider_data.get("models", {})
+    if not isinstance(models, dict):
+        return None
+
+    return models
+
+
+def _find_model_entry(models: Dict[str, Any], model: str) -> Optional[Dict[str, Any]]:
+    """Find a model entry by exact match, then case-insensitive fallback."""
+    # Exact match
+    entry = models.get(model)
+    if isinstance(entry, dict):
+        return entry
+
+    # Case-insensitive match
+    model_lower = model.lower()
+    for mid, mdata in models.items():
+        if mid.lower() == model_lower and isinstance(mdata, dict):
+            return mdata
+
+    return None
+
+
+def get_model_capabilities(provider: str, model: str) -> Optional[ModelCapabilities]:
+    """Look up full capability metadata from models.dev cache.
+
+    Uses the existing fetch_models_dev() and PROVIDER_TO_MODELS_DEV mapping.
+    Returns None if model not found.
+
+    Extracts from model entry fields:
+      - reasoning  (bool)  → supports_reasoning
+      - tool_call  (bool)  → supports_tools
+      - attachment (bool)  → supports_vision
+      - limit.context (int) → context_window
+      - limit.output  (int) → max_output_tokens
+      - family     (str)   → model_family
+    """
+    models = _get_provider_models(provider)
+    if models is None:
+        return None
+
+    entry = _find_model_entry(models, model)
+    if entry is None:
+        return None
+
+    # Extract capability flags (default to False if missing)
+    supports_tools = bool(entry.get("tool_call", False))
+    supports_vision = bool(entry.get("attachment", False))
+    supports_reasoning = bool(entry.get("reasoning", False))
+
+    # Extract limits
+    limit = entry.get("limit", {})
+    if not isinstance(limit, dict):
+        limit = {}
+
+    ctx = limit.get("context")
+    context_window = int(ctx) if isinstance(ctx, (int, float)) and ctx > 0 else 200000
+
+    out = limit.get("output")
+    max_output_tokens = int(out) if isinstance(out, (int, float)) and out > 0 else 8192
+
+    model_family = entry.get("family", "") or ""
+
+    return ModelCapabilities(
+        supports_tools=supports_tools,
+        supports_vision=supports_vision,
+        supports_reasoning=supports_reasoning,
+        context_window=context_window,
+        max_output_tokens=max_output_tokens,
+        model_family=model_family,
+    )
+
+
+def list_provider_models(provider: str) -> List[str]:
+    """Return all model IDs for a provider from models.dev.
+
+    Returns an empty list if the provider is unknown or has no data.
+    """
+    models = _get_provider_models(provider)
+    if models is None:
+        return []
+    return list(models.keys())
+
+
+def search_models_dev(
+    query: str, provider: str = None, limit: int = 5
+) -> List[Dict[str, Any]]:
+    """Fuzzy search across models.dev catalog. Returns matching model entries.
+
+    Args:
+        query: Search string to match against model IDs.
+        provider: Optional Hermes provider ID to restrict search scope.
+                  If None, searches across all providers in PROVIDER_TO_MODELS_DEV.
+        limit: Maximum number of results to return.
+
+    Returns:
+        List of dicts, each containing 'provider', 'model_id', and the full
+        model 'entry' from models.dev.
+    """
+    data = fetch_models_dev()
+    if not data:
+        return []
+
+    # Build list of (provider_id, model_id, entry) candidates
+    candidates: List[tuple] = []
+
+    if provider is not None:
+        # Search only the specified provider
+        mdev_provider_id = PROVIDER_TO_MODELS_DEV.get(provider)
+        if not mdev_provider_id:
+            return []
+        provider_data = data.get(mdev_provider_id, {})
+        if isinstance(provider_data, dict):
+            models = provider_data.get("models", {})
+            if isinstance(models, dict):
+                for mid, mdata in models.items():
+                    candidates.append((provider, mid, mdata))
+    else:
+        # Search across all mapped providers
+        for hermes_prov, mdev_prov in PROVIDER_TO_MODELS_DEV.items():
+            provider_data = data.get(mdev_prov, {})
+            if isinstance(provider_data, dict):
+                models = provider_data.get("models", {})
+                if isinstance(models, dict):
+                    for mid, mdata in models.items():
+                        candidates.append((hermes_prov, mid, mdata))
+
+    if not candidates:
+        return []
+
+    # Use difflib for fuzzy matching — case-insensitive comparison
+    model_ids_lower = [c[1].lower() for c in candidates]
+    query_lower = query.lower()
+
+    # First try exact substring matches (more intuitive than pure edit-distance)
+    substring_matches = []
+    for prov, mid, mdata in candidates:
+        if query_lower in mid.lower():
+            substring_matches.append({"provider": prov, "model_id": mid, "entry": mdata})
+
+    # Then add difflib fuzzy matches for any remaining slots
+    fuzzy_ids = difflib.get_close_matches(
+        query_lower, model_ids_lower, n=limit * 2, cutoff=0.4
+    )
+
+    seen_ids: set = set()
+    results: List[Dict[str, Any]] = []
+
+    # Prioritize substring matches
+    for match in substring_matches:
+        key = (match["provider"], match["model_id"])
+        if key not in seen_ids:
+            seen_ids.add(key)
+            results.append(match)
+            if len(results) >= limit:
+                return results
+
+    # Add fuzzy matches
+    for fid in fuzzy_ids:
+        # Find original-case candidates matching this lowered ID
+        for prov, mid, mdata in candidates:
+            if mid.lower() == fid:
+                key = (prov, mid)
+                if key not in seen_ids:
+                    seen_ids.add(key)
+                    results.append({"provider": prov, "model_id": mid, "entry": mdata})
+                    if len(results) >= limit:
+                        return results
+
+    return results
+
+
+# ---------------------------------------------------------------------------
+# Rich dataclass constructors — parse raw models.dev JSON into dataclasses
+# ---------------------------------------------------------------------------
+
+def _parse_model_info(model_id: str, raw: Dict[str, Any], provider_id: str) -> ModelInfo:
+    """Convert a raw models.dev model entry dict into a ModelInfo dataclass."""
+    limit = raw.get("limit") or {}
+    if not isinstance(limit, dict):
+        limit = {}
+
+    cost = raw.get("cost") or {}
+    if not isinstance(cost, dict):
+        cost = {}
+
+    modalities = raw.get("modalities") or {}
+    if not isinstance(modalities, dict):
+        modalities = {}
+
+    input_mods = modalities.get("input") or []
+    output_mods = modalities.get("output") or []
+
+    ctx = limit.get("context")
+    ctx_int = int(ctx) if isinstance(ctx, (int, float)) and ctx > 0 else 0
+    out = limit.get("output")
+    out_int = int(out) if isinstance(out, (int, float)) and out > 0 else 0
+    inp = limit.get("input")
+    inp_int = int(inp) if isinstance(inp, (int, float)) and inp > 0 else None
+
+    return ModelInfo(
+        id=model_id,
+        name=raw.get("name", "") or model_id,
+        family=raw.get("family", "") or "",
+        provider_id=provider_id,
+        reasoning=bool(raw.get("reasoning", False)),
+        tool_call=bool(raw.get("tool_call", False)),
+        attachment=bool(raw.get("attachment", False)),
+        temperature=bool(raw.get("temperature", False)),
+        structured_output=bool(raw.get("structured_output", False)),
+        open_weights=bool(raw.get("open_weights", False)),
+        input_modalities=tuple(input_mods) if isinstance(input_mods, list) else (),
+        output_modalities=tuple(output_mods) if isinstance(output_mods, list) else (),
+        context_window=ctx_int,
+        max_output=out_int,
+        max_input=inp_int,
+        cost_input=float(cost.get("input", 0) or 0),
+        cost_output=float(cost.get("output", 0) or 0),
+        cost_cache_read=float(cost["cache_read"]) if "cache_read" in cost and cost["cache_read"] is not None else None,
+        cost_cache_write=float(cost["cache_write"]) if "cache_write" in cost and cost["cache_write"] is not None else None,
+        knowledge_cutoff=raw.get("knowledge", "") or "",
+        release_date=raw.get("release_date", "") or "",
+        status=raw.get("status", "") or "",
+        interleaved=raw.get("interleaved", False),
+    )
+
+
+def _parse_provider_info(provider_id: str, raw: Dict[str, Any]) -> ProviderInfo:
+    """Convert a raw models.dev provider entry dict into a ProviderInfo."""
+    env = raw.get("env") or []
+    models = raw.get("models") or {}
+    return ProviderInfo(
+        id=provider_id,
+        name=raw.get("name", "") or provider_id,
+        env=tuple(env) if isinstance(env, list) else (),
+        api=raw.get("api", "") or "",
+        doc=raw.get("doc", "") or "",
+        model_count=len(models) if isinstance(models, dict) else 0,
+    )
+
+
+# ---------------------------------------------------------------------------
+# Provider-level queries
+# ---------------------------------------------------------------------------
+
+def get_provider_info(provider_id: str) -> Optional[ProviderInfo]:
+    """Get full provider metadata from models.dev.
+
+    Accepts either a Hermes provider ID (e.g. "kilocode") or a models.dev
+    ID (e.g. "kilo").  Returns None if the provider is not in the catalog.
+    """
+    # Resolve Hermes ID → models.dev ID
+    mdev_id = PROVIDER_TO_MODELS_DEV.get(provider_id, provider_id)
+
+    data = fetch_models_dev()
+    raw = data.get(mdev_id)
+    if not isinstance(raw, dict):
+        return None
+
+    return _parse_provider_info(mdev_id, raw)
+
+
+def list_all_providers() -> Dict[str, ProviderInfo]:
+    """Return all providers from models.dev as {provider_id: ProviderInfo}.
+
+    Returns the full catalog — 109+ providers.  For providers that have
+    a Hermes alias, both the models.dev ID and the Hermes ID are included.
+    """
+    data = fetch_models_dev()
+    result: Dict[str, ProviderInfo] = {}
+
+    for pid, pdata in data.items():
+        if isinstance(pdata, dict):
+            info = _parse_provider_info(pid, pdata)
+            result[pid] = info
+
+    return result
+
+
+def get_providers_for_env_var(env_var: str) -> List[str]:
+    """Reverse lookup: find all providers that use a given env var.
+
+    Useful for auto-detection: "user has ANTHROPIC_API_KEY set, which
+    providers does that enable?"
+
+    Returns list of models.dev provider IDs.
+    """
+    data = fetch_models_dev()
+    matches: List[str] = []
+
+    for pid, pdata in data.items():
+        if isinstance(pdata, dict):
+            env = pdata.get("env", [])
+            if isinstance(env, list) and env_var in env:
+                matches.append(pid)
+
+    return matches
+
+
+# ---------------------------------------------------------------------------
+# Model-level queries (rich ModelInfo)
+# ---------------------------------------------------------------------------
+
+def get_model_info(
+    provider_id: str, model_id: str
+) -> Optional[ModelInfo]:
+    """Get full model metadata from models.dev.
+
+    Accepts Hermes or models.dev provider ID.  Tries exact match then
+    case-insensitive fallback.  Returns None if not found.
+    """
+    mdev_id = PROVIDER_TO_MODELS_DEV.get(provider_id, provider_id)
+
+    data = fetch_models_dev()
+    pdata = data.get(mdev_id)
+    if not isinstance(pdata, dict):
+        return None
+
+    models = pdata.get("models", {})
+    if not isinstance(models, dict):
+        return None
+
+    # Exact match
+    raw = models.get(model_id)
+    if isinstance(raw, dict):
+        return _parse_model_info(model_id, raw, mdev_id)
+
+    # Case-insensitive fallback
+    model_lower = model_id.lower()
+    for mid, mdata in models.items():
+        if mid.lower() == model_lower and isinstance(mdata, dict):
+            return _parse_model_info(mid, mdata, mdev_id)
+
+    return None
+
+
+def get_model_info_any_provider(model_id: str) -> Optional[ModelInfo]:
+    """Search all providers for a model by ID.
+
+    Useful when you have a full slug like "anthropic/claude-sonnet-4.6" or
+    a bare name and want to find it anywhere.  Checks Hermes-mapped providers
+    first, then falls back to all models.dev providers.
+    """
+    data = fetch_models_dev()
+
+    # Try Hermes-mapped providers first (more likely what the user wants)
+    for hermes_id, mdev_id in PROVIDER_TO_MODELS_DEV.items():
+        pdata = data.get(mdev_id)
+        if not isinstance(pdata, dict):
+            continue
+        models = pdata.get("models", {})
+        if not isinstance(models, dict):
+            continue
+
+        raw = models.get(model_id)
+        if isinstance(raw, dict):
+            return _parse_model_info(model_id, raw, mdev_id)
+
+        # Case-insensitive
+        model_lower = model_id.lower()
+        for mid, mdata in models.items():
+            if mid.lower() == model_lower and isinstance(mdata, dict):
+                return _parse_model_info(mid, mdata, mdev_id)
+
+    # Fall back to ALL providers
+    for pid, pdata in data.items():
+        if pid in _get_reverse_mapping():
+            continue  # already checked
+        if not isinstance(pdata, dict):
+            continue
+        models = pdata.get("models", {})
+        if not isinstance(models, dict):
+            continue
+
+        raw = models.get(model_id)
+        if isinstance(raw, dict):
+            return _parse_model_info(model_id, raw, pid)
+
+    return None
+
+
+def list_provider_model_infos(provider_id: str) -> List[ModelInfo]:
+    """Return all models for a provider as ModelInfo objects.
+
+    Filters out deprecated models by default.
+    """
+    mdev_id = PROVIDER_TO_MODELS_DEV.get(provider_id, provider_id)
+
+    data = fetch_models_dev()
+    pdata = data.get(mdev_id)
+    if not isinstance(pdata, dict):
+        return []
+
+    models = pdata.get("models", {})
+    if not isinstance(models, dict):
+        return []
+
+    result: List[ModelInfo] = []
+    for mid, mdata in models.items():
+        if not isinstance(mdata, dict):
+            continue
+        status = mdata.get("status", "")
+        if status == "deprecated":
+            continue
+        result.append(_parse_model_info(mid, mdata, mdev_id))
+
+    return result

cli.py

@@ -3519,6 +3519,167 @@ class HermesCLI:
         remaining = len(self.conversation_history)
         print(f"  {remaining} message(s) remaining in history.")
     
+    def _handle_model_switch(self, cmd_original: str):
+        """Handle /model command — switch model for this session.
+
+        Supports:
+          /model                              — show current model + usage hints
+          /model <name>                       — switch for this session only
+          /model <name> --global              — switch and persist to config.yaml
+          /model <name> --provider <provider> — switch provider + model
+          /model --provider <provider>        — switch to provider, auto-detect model
+        """
+        from hermes_cli.model_switch import switch_model, parse_model_flags, list_authenticated_providers
+        from hermes_cli.providers import get_label
+
+        # Parse args from the original command
+        parts = cmd_original.split(None, 1)  # split off '/model'
+        raw_args = parts[1].strip() if len(parts) > 1 else ""
+
+        # Parse --provider and --global flags
+        model_input, explicit_provider, persist_global = parse_model_flags(raw_args)
+
+        # No args at all: show available providers + models
+        if not model_input and not explicit_provider:
+            model_display = self.model or "unknown"
+            provider_display = get_label(self.provider) if self.provider else "unknown"
+            _cprint(f"  Current: {model_display} on {provider_display}")
+            _cprint("")
+
+            # Show authenticated providers with top models
+            try:
+                # Load user providers from config
+                user_provs = None
+                try:
+                    from hermes_cli.config import load_config
+                    cfg = load_config()
+                    user_provs = cfg.get("providers")
+                except Exception:
+                    pass
+
+                providers = list_authenticated_providers(
+                    current_provider=self.provider or "",
+                    user_providers=user_provs,
+                    max_models=6,
+                )
+                if providers:
+                    for p in providers:
+                        tag = " (current)" if p["is_current"] else ""
+                        _cprint(f"  {p['name']} [--provider {p['slug']}]{tag}:")
+                        if p["models"]:
+                            model_strs = ", ".join(p["models"])
+                            extra = f"  (+{p['total_models'] - len(p['models'])} more)" if p["total_models"] > len(p["models"]) else ""
+                            _cprint(f"    {model_strs}{extra}")
+                        elif p.get("api_url"):
+                            _cprint(f"    {p['api_url']} (use /model <name> --provider {p['slug']})")
+                        else:
+                            _cprint(f"    (no models listed)")
+                        _cprint("")
+                else:
+                    _cprint("  No authenticated providers found.")
+                    _cprint("")
+            except Exception:
+                pass
+
+            # Aliases
+            from hermes_cli.model_switch import MODEL_ALIASES
+            alias_list = ", ".join(sorted(MODEL_ALIASES.keys()))
+            _cprint(f"  Aliases: {alias_list}")
+            _cprint("")
+            _cprint("  /model <name>                        switch model")
+            _cprint("  /model <name> --provider <slug>      switch provider")
+            _cprint("  /model <name> --global               persist to config")
+            return
+
+        # Perform the switch
+        result = switch_model(
+            raw_input=model_input,
+            current_provider=self.provider or "",
+            current_model=self.model or "",
+            current_base_url=self.base_url or "",
+            current_api_key=self.api_key or "",
+            is_global=persist_global,
+            explicit_provider=explicit_provider,
+        )
+
+        if not result.success:
+            _cprint(f"  ✗ {result.error_message}")
+            return
+
+        # Apply to CLI state
+        old_model = self.model
+        self.model = result.new_model
+        self.provider = result.target_provider
+        if result.api_key:
+            self.api_key = result.api_key
+        if result.base_url:
+            self.base_url = result.base_url
+        if result.api_mode:
+            self.api_mode = result.api_mode
+
+        # Apply to running agent (in-place swap)
+        if self.agent is not None:
+            try:
+                self.agent.switch_model(
+                    new_model=result.new_model,
+                    new_provider=result.target_provider,
+                    api_key=result.api_key,
+                    base_url=result.base_url,
+                    api_mode=result.api_mode,
+                )
+            except Exception as exc:
+                _cprint(f"  ⚠ Agent swap failed ({exc}); change applied to next session.")
+
+        # Display confirmation with full metadata
+        provider_label = result.provider_label or result.target_provider
+        _cprint(f"  ✓ Model switched: {result.new_model}")
+        _cprint(f"    Provider: {provider_label}")
+
+        # Rich metadata from models.dev
+        mi = result.model_info
+        if mi:
+            if mi.context_window:
+                _cprint(f"    Context: {mi.context_window:,} tokens")
+            if mi.max_output:
+                _cprint(f"    Max output: {mi.max_output:,} tokens")
+            if mi.has_cost_data():
+                _cprint(f"    Cost: {mi.format_cost()}")
+            _cprint(f"    Capabilities: {mi.format_capabilities()}")
+        else:
+            # Fallback to old context length lookup
+            try:
+                from agent.model_metadata import get_model_context_length
+                ctx = get_model_context_length(
+                    result.new_model,
+                    base_url=result.base_url or self.base_url,
+                    api_key=result.api_key or self.api_key,
+                    provider=result.target_provider,
+                )
+                _cprint(f"    Context: {ctx:,} tokens")
+            except Exception:
+                pass
+
+        # Cache notice
+        cache_enabled = (
+            ("openrouter" in (result.base_url or "").lower() and "claude" in result.new_model.lower())
+            or result.api_mode == "anthropic_messages"
+        )
+        if cache_enabled:
+            _cprint("    Prompt caching: enabled")
+
+        # Warning from validation
+        if result.warning_message:
+            _cprint(f"    ⚠ {result.warning_message}")
+
+        # Persistence
+        if persist_global:
+            save_config_value("model.name", result.new_model)
+            if result.provider_changed:
+                save_config_value("model.provider", result.target_provider)
+            _cprint("    Saved to config.yaml (--global)")
+        else:
+            _cprint("    (session only — add --global to persist)")
+
     def _show_model_and_providers(self):
         """Show current model + provider and list all authenticated providers.
 
@@ -4134,6 +4295,8 @@ class HermesCLI:
             self.new_session()
         elif canonical == "resume":
             self._handle_resume_command(cmd_original)
+        elif canonical == "model":
+            self._handle_model_switch(cmd_original)
         elif canonical == "provider":
             self._show_model_and_providers()
         elif canonical == "prompt":

gateway/run.py

@@ -509,6 +509,9 @@ class GatewayRunner:
         self._effective_model: Optional[str] = None
         self._effective_provider: Optional[str] = None
 
+        # Per-session model overrides from /model command.
+        # Key: session_key, Value: dict with model/provider/api_key/base_url/api_mode
+        self._session_model_overrides: Dict[str, Dict[str, str]] = {}
         # Track pending exec approvals per session
         # Key: session_key, Value: {"command": str, "pattern_key": str, ...}
         self._pending_approvals: Dict[str, Dict[str, Any]] = {}
@@ -1859,6 +1862,10 @@ class GatewayRunner:
                     adapter._pending_messages[_quick_key] = queued_event
                 return "Queued for the next turn."
 
+            # /model must not be used while the agent is running.
+            if _cmd_def_inner and _cmd_def_inner.name == "model":
+                return "Agent is running — wait or /stop first, then switch models."
+
             # /approve and /deny must bypass the running-agent interrupt path.
             # The agent thread is blocked on a threading.Event inside
             # tools/approval.py — sending an interrupt won't unblock it.
@@ -1958,6 +1965,9 @@ class GatewayRunner:
         if canonical == "yolo":
             return await self._handle_yolo_command(event)
 
+        if canonical == "model":
+            return await self._handle_model_command(event)
+
         if canonical == "provider":
             return await self._handle_provider_command(event)
         
@@ -3268,6 +3278,196 @@ class GatewayRunner:
             lines.append(f"_(Requested page {requested_page} was out of range, showing page {page}.)_")
         return "\n".join(lines)
     
+    async def _handle_model_command(self, event: MessageEvent) -> str:
+        """Handle /model command — switch model for this session.
+
+        Supports:
+          /model                              — show current model info
+          /model <name>                       — switch for this session only
+          /model <name> --global              — switch and persist to config.yaml
+          /model <name> --provider <provider> — switch provider + model
+          /model --provider <provider>        — switch to provider, auto-detect model
+        """
+        import yaml
+        from hermes_cli.model_switch import (
+            switch_model as _switch_model, parse_model_flags,
+            list_authenticated_providers,
+        )
+        from hermes_cli.providers import get_label
+
+        raw_args = event.get_command_args().strip()
+
+        # Parse --provider and --global flags
+        model_input, explicit_provider, persist_global = parse_model_flags(raw_args)
+
+        # Read current model/provider from config
+        current_model = ""
+        current_provider = "openrouter"
+        current_base_url = ""
+        current_api_key = ""
+        user_provs = None
+        config_path = _hermes_home / "config.yaml"
+        try:
+            if config_path.exists():
+                with open(config_path, encoding="utf-8") as f:
+                    cfg = yaml.safe_load(f) or {}
+                model_cfg = cfg.get("model", {})
+                if isinstance(model_cfg, dict):
+                    current_model = model_cfg.get("name", "")
+                    current_provider = model_cfg.get("provider", current_provider)
+                    current_base_url = model_cfg.get("base_url", "")
+                user_provs = cfg.get("providers")
+        except Exception:
+            pass
+
+        # Check for session override
+        source = event.source
+        session_key = self._session_key_for_source(source)
+        override = getattr(self, "_session_model_overrides", {}).get(session_key, {})
+        if override:
+            current_model = override.get("model", current_model)
+            current_provider = override.get("provider", current_provider)
+            current_base_url = override.get("base_url", current_base_url)
+            current_api_key = override.get("api_key", current_api_key)
+
+        # No args: show authenticated providers with models
+        if not model_input and not explicit_provider:
+            provider_label = get_label(current_provider)
+            lines = [f"Current: `{current_model or 'unknown'}` on {provider_label}", ""]
+
+            try:
+                providers = list_authenticated_providers(
+                    current_provider=current_provider,
+                    user_providers=user_provs,
+                    max_models=5,
+                )
+                for p in providers:
+                    tag = " (current)" if p["is_current"] else ""
+                    lines.append(f"**{p['name']}** `--provider {p['slug']}`{tag}:")
+                    if p["models"]:
+                        model_strs = ", ".join(f"`{m}`" for m in p["models"])
+                        extra = f" (+{p['total_models'] - len(p['models'])} more)" if p["total_models"] > len(p["models"]) else ""
+                        lines.append(f"  {model_strs}{extra}")
+                    elif p.get("api_url"):
+                        lines.append(f"  `{p['api_url']}`")
+                    lines.append("")
+            except Exception:
+                pass
+
+            lines.append("`/model <name>` — switch model")
+            lines.append("`/model <name> --provider <slug>` — switch provider")
+            lines.append("`/model <name> --global` — persist")
+            return "\n".join(lines)
+
+        # Perform the switch
+        result = _switch_model(
+            raw_input=model_input,
+            current_provider=current_provider,
+            current_model=current_model,
+            current_base_url=current_base_url,
+            current_api_key=current_api_key,
+            is_global=persist_global,
+            explicit_provider=explicit_provider,
+        )
+
+        if not result.success:
+            return f"Error: {result.error_message}"
+
+        # If there's a cached agent, update it in-place
+        cached_entry = None
+        _cache_lock = getattr(self, "_agent_cache_lock", None)
+        _cache = getattr(self, "_agent_cache", None)
+        if _cache_lock and _cache is not None:
+            with _cache_lock:
+                cached_entry = _cache.get(session_key)
+
+        if cached_entry and cached_entry[0] is not None:
+            try:
+                cached_entry[0].switch_model(
+                    new_model=result.new_model,
+                    new_provider=result.target_provider,
+                    api_key=result.api_key,
+                    base_url=result.base_url,
+                    api_mode=result.api_mode,
+                )
+            except Exception as exc:
+                logger.warning("In-place model switch failed for cached agent: %s", exc)
+
+        # Store session override so next agent creation uses the new model
+        if not hasattr(self, "_session_model_overrides"):
+            self._session_model_overrides = {}
+        self._session_model_overrides[session_key] = {
+            "model": result.new_model,
+            "provider": result.target_provider,
+            "api_key": result.api_key,
+            "base_url": result.base_url,
+            "api_mode": result.api_mode,
+        }
+
+        # Persist to config if --global
+        if persist_global:
+            try:
+                if config_path.exists():
+                    with open(config_path, encoding="utf-8") as f:
+                        cfg = yaml.safe_load(f) or {}
+                else:
+                    cfg = {}
+                model_cfg = cfg.setdefault("model", {})
+                model_cfg["name"] = result.new_model
+                model_cfg["provider"] = result.target_provider
+                if result.base_url:
+                    model_cfg["base_url"] = result.base_url
+                from hermes_cli.config import save_config
+                save_config(cfg)
+            except Exception as e:
+                logger.warning("Failed to persist model switch: %s", e)
+
+        # Build confirmation message with full metadata
+        provider_label = result.provider_label or result.target_provider
+        lines = [f"Model switched to `{result.new_model}`"]
+        lines.append(f"Provider: {provider_label}")
+
+        # Rich metadata from models.dev
+        mi = result.model_info
+        if mi:
+            if mi.context_window:
+                lines.append(f"Context: {mi.context_window:,} tokens")
+            if mi.max_output:
+                lines.append(f"Max output: {mi.max_output:,} tokens")
+            if mi.has_cost_data():
+                lines.append(f"Cost: {mi.format_cost()}")
+            lines.append(f"Capabilities: {mi.format_capabilities()}")
+        else:
+            try:
+                from agent.model_metadata import get_model_context_length
+                ctx = get_model_context_length(
+                    result.new_model,
+                    base_url=result.base_url or current_base_url,
+                    api_key=result.api_key or current_api_key,
+                    provider=result.target_provider,
+                )
+                lines.append(f"Context: {ctx:,} tokens")
+            except Exception:
+                pass
+
+        # Cache notice
+        cache_enabled = (
+            ("openrouter" in (result.base_url or "").lower() and "claude" in result.new_model.lower())
+            or result.api_mode == "anthropic_messages"
+        )
+        if cache_enabled:
+            lines.append("Prompt caching: enabled")
+
+        if result.warning_message:
+            lines.append(f"Warning: {result.warning_message}")
+
+        if persist_global:
+            lines.append("Saved to config.yaml (`--global`)")
+        else:
+            lines.append("_(session only -- add `--global` to persist)_")
+
+        return "\n".join(lines)
+
     async def _handle_provider_command(self, event: MessageEvent) -> str:
         """Handle /provider command - show available providers."""
         import yaml

hermes_cli/commands.py

@@ -84,6 +84,7 @@ COMMAND_REGISTRY: list[CommandDef] = [
     # Configuration
     CommandDef("config", "Show current configuration", "Configuration",
                cli_only=True),
+    CommandDef("model", "Switch model for this session", "Configuration", args_hint="[model] [--global]"),
     CommandDef("provider", "Show available providers and current provider",
                "Configuration"),
     CommandDef("prompt", "View/set custom system prompt", "Configuration",

hermes_cli/config.py

@@ -199,6 +199,7 @@ def ensure_hermes_home():
 
 DEFAULT_CONFIG = {
     "model": "",
+    "providers": {},
     "fallback_providers": [],
     "credential_pool_strategies": {},
     "toolsets": ["hermes-cli"],
@@ -531,7 +532,7 @@ DEFAULT_CONFIG = {
     },
 
     # Config schema version - bump this when adding new required fields
-    "_config_version": 11,
+    "_config_version": 12,
 }
 
 # =============================================================================
@@ -1312,6 +1313,69 @@ def migrate_config(interactive: bool = True, quiet: bool = False) -> Dict[str, A
         except Exception:
             pass
 
+    # ── Version 11 → 12: migrate custom_providers list → providers dict ──
+    if current_ver < 12:
+        config = load_config()
+        custom_list = config.get("custom_providers")
+        if isinstance(custom_list, list) and custom_list:
+            providers_dict = config.get("providers", {})
+            if not isinstance(providers_dict, dict):
+                providers_dict = {}
+            migrated_count = 0
+            for entry in custom_list:
+                if not isinstance(entry, dict):
+                    continue
+                old_name = entry.get("name", "")
+                old_url = entry.get("base_url", "") or entry.get("url", "") or ""
+                old_key = entry.get("api_key", "")
+                if not old_url:
+                    continue  # skip entries with no URL
+
+                # Generate a kebab-case key from the display name
+                key = old_name.strip().lower().replace(" ", "-").replace("(", "").replace(")", "")
+                # Remove consecutive hyphens and trailing hyphens
+                while "--" in key:
+                    key = key.replace("--", "-")
+                key = key.strip("-")
+                if not key:
+                    # Fallback: derive from URL hostname
+                    try:
+                        from urllib.parse import urlparse
+                        parsed = urlparse(old_url)
+                        key = (parsed.hostname or "endpoint").replace(".", "-")
+                    except Exception:
+                        key = f"endpoint-{migrated_count}"
+
+                # Don't overwrite existing entries
+                if key in providers_dict:
+                    key = f"{key}-{migrated_count}"
+
+                new_entry = {"api": old_url}
+                if old_name:
+                    new_entry["name"] = old_name
+                if old_key and old_key not in ("no-key", "no-key-required", ""):
+                    new_entry["api_key"] = old_key
+
+                # Carry over model and api_mode if present
+                if entry.get("model"):
+                    new_entry["default_model"] = entry["model"]
+                if entry.get("api_mode"):
+                    new_entry["transport"] = entry["api_mode"]
+
+                providers_dict[key] = new_entry
+                migrated_count += 1
+
+            if migrated_count > 0:
+                config["providers"] = providers_dict
+                # Remove the old list
+                del config["custom_providers"]
+                save_config(config)
+                if not quiet:
+                    print(f"  ✓ Migrated {migrated_count} custom provider(s) to providers: section")
+                    for key in list(providers_dict.keys())[-migrated_count:]:
+                        ep = providers_dict[key]
+                        print(f"    → {key}: {ep.get('api', '')}")
+
     if current_ver < latest_ver and not quiet:
         print(f"Config version: {current_ver} → {latest_ver}")
     

hermes_cli/model_normalize.py

@@ -0,0 +1,359 @@
+"""Per-provider model name normalization.
+
+Different LLM providers expect model identifiers in different formats:
+
+- **Aggregators** (OpenRouter, Nous, AI Gateway, Kilo Code) need
+  ``vendor/model`` slugs like ``anthropic/claude-sonnet-4.6``.
+- **Anthropic** native API expects bare names with dots replaced by
+  hyphens: ``claude-sonnet-4-6``.
+- **Copilot** expects bare names *with* dots preserved:
+  ``claude-sonnet-4.6``.
+- **OpenCode** (Zen & Go) follows the same dot-to-hyphen convention as
+  Anthropic: ``claude-sonnet-4-6``.
+- **DeepSeek** only accepts two model identifiers:
+  ``deepseek-chat`` and ``deepseek-reasoner``.
+- **Custom** and remaining providers pass the name through as-is.
+
+This module centralises that translation so callers can simply write::
+
+    api_model = normalize_model_for_provider(user_input, provider)
+
+Inspired by Clawdbot's ``normalizeAnthropicModelId`` pattern.
+"""
+
+from __future__ import annotations
+
+from typing import Optional
+
+# ---------------------------------------------------------------------------
+# Vendor prefix mapping
+# ---------------------------------------------------------------------------
+# Maps the first hyphen-delimited token of a bare model name to the vendor
+# slug used by aggregator APIs (OpenRouter, Nous, etc.).
+#
+# Example: "claude-sonnet-4.6" -> first token "claude" -> vendor "anthropic"
+#          -> aggregator slug: "anthropic/claude-sonnet-4.6"
+
+_VENDOR_PREFIXES: dict[str, str] = {
+    "claude": "anthropic",
+    "gpt": "openai",
+    "o1": "openai",
+    "o3": "openai",
+    "o4": "openai",
+    "gemini": "google",
+    "deepseek": "deepseek",
+    "glm": "z-ai",
+    "kimi": "moonshotai",
+    "minimax": "minimax",
+    "grok": "x-ai",
+    "qwen": "qwen",
+    "mimo": "xiaomi",
+    "nemotron": "nvidia",
+    "llama": "meta-llama",
+    "step": "stepfun",
+    "trinity": "arcee-ai",
+}
+
+# Providers whose APIs consume vendor/model slugs.
+_AGGREGATOR_PROVIDERS: frozenset[str] = frozenset({
+    "openrouter",
+    "nous",
+    "ai-gateway",
+    "kilocode",
+})
+
+# Providers that want bare names with dots replaced by hyphens.
+_DOT_TO_HYPHEN_PROVIDERS: frozenset[str] = frozenset({
+    "anthropic",
+    "opencode-zen",
+    "opencode-go",
+})
+
+# Providers that want bare names with dots preserved.
+_STRIP_VENDOR_ONLY_PROVIDERS: frozenset[str] = frozenset({
+    "copilot",
+    "copilot-acp",
+})
+
+# Providers whose own naming is authoritative -- pass through unchanged.
+_PASSTHROUGH_PROVIDERS: frozenset[str] = frozenset({
+    "zai",
+    "kimi-coding",
+    "minimax",
+    "minimax-cn",
+    "alibaba",
+    "huggingface",
+    "openai-codex",
+    "custom",
+})
+
+# ---------------------------------------------------------------------------
+# DeepSeek special handling
+# ---------------------------------------------------------------------------
+# DeepSeek's API only recognises exactly two model identifiers.  We map
+# common aliases and patterns to the canonical names.
+
+_DEEPSEEK_REASONER_KEYWORDS: frozenset[str] = frozenset({
+    "reasoner",
+    "r1",
+    "think",
+    "reasoning",
+    "cot",
+})
+
+_DEEPSEEK_CANONICAL_MODELS: frozenset[str] = frozenset({
+    "deepseek-chat",
+    "deepseek-reasoner",
+})
+
+
+def _normalize_for_deepseek(model_name: str) -> str:
+    """Map any model input to one of DeepSeek's two accepted identifiers.
+
+    Rules:
+    - Already ``deepseek-chat`` or ``deepseek-reasoner`` -> pass through.
+    - Contains any reasoner keyword (r1, think, reasoning, cot, reasoner)
+      -> ``deepseek-reasoner``.
+    - Everything else -> ``deepseek-chat``.
+
+    Args:
+        model_name: The bare model name (vendor prefix already stripped).
+
+    Returns:
+        One of ``"deepseek-chat"`` or ``"deepseek-reasoner"``.
+    """
+    bare = _strip_vendor_prefix(model_name).lower()
+
+    if bare in _DEEPSEEK_CANONICAL_MODELS:
+        return bare
+
+    # Check for reasoner-like keywords anywhere in the name
+    for keyword in _DEEPSEEK_REASONER_KEYWORDS:
+        if keyword in bare:
+            return "deepseek-reasoner"
+
+    return "deepseek-chat"
+
+
+# ---------------------------------------------------------------------------
+# Helper utilities
+# ---------------------------------------------------------------------------
+
+def _strip_vendor_prefix(model_name: str) -> str:
+    """Remove a ``vendor/`` prefix if present.
+
+    Examples::
+
+        >>> _strip_vendor_prefix("anthropic/claude-sonnet-4.6")
+        'claude-sonnet-4.6'
+        >>> _strip_vendor_prefix("claude-sonnet-4.6")
+        'claude-sonnet-4.6'
+        >>> _strip_vendor_prefix("meta-llama/llama-4-scout")
+        'llama-4-scout'
+    """
+    if "/" in model_name:
+        return model_name.split("/", 1)[1]
+    return model_name
+
+
+def _dots_to_hyphens(model_name: str) -> str:
+    """Replace dots with hyphens in a model name.
+
+    Anthropic's native API uses hyphens where marketing names use dots:
+    ``claude-sonnet-4.6`` -> ``claude-sonnet-4-6``.
+    """
+    return model_name.replace(".", "-")
+
+
+def detect_vendor(model_name: str) -> Optional[str]:
+    """Detect the vendor slug from a bare model name.
+
+    Uses the first hyphen-delimited token of the model name to look up
+    the corresponding vendor in ``_VENDOR_PREFIXES``.  Also handles
+    case-insensitive matching and special patterns.
+
+    Args:
+        model_name: A model name, optionally already including a
+            ``vendor/`` prefix.  If a prefix is present it is used
+            directly.
+
+    Returns:
+        The vendor slug (e.g. ``"anthropic"``, ``"openai"``) or ``None``
+        if no vendor can be confidently detected.
+
+    Examples::
+
+        >>> detect_vendor("claude-sonnet-4.6")
+        'anthropic'
+        >>> detect_vendor("gpt-5.4-mini")
+        'openai'
+        >>> detect_vendor("anthropic/claude-sonnet-4.6")
+        'anthropic'
+        >>> detect_vendor("my-custom-model")
+    """
+    name = model_name.strip()
+    if not name:
+        return None
+
+    # If there's already a vendor/ prefix, extract it
+    if "/" in name:
+        return name.split("/", 1)[0].lower() or None
+
+    name_lower = name.lower()
+
+    # Try first hyphen-delimited token (exact match)
+    first_token = name_lower.split("-")[0]
+    if first_token in _VENDOR_PREFIXES:
+        return _VENDOR_PREFIXES[first_token]
+
+    # Handle patterns where the first token includes version digits,
+    # e.g. "qwen3.5-plus" -> first token "qwen3.5", but prefix is "qwen"
+    for prefix, vendor in _VENDOR_PREFIXES.items():
+        if name_lower.startswith(prefix):
+            return vendor
+
+    return None
+
+
+def _prepend_vendor(model_name: str) -> str:
+    """Prepend the detected ``vendor/`` prefix if missing.
+
+    Used for aggregator providers that require ``vendor/model`` format.
+    If the name already contains a ``/``, it is returned as-is.
+    If no vendor can be detected, the name is returned unchanged
+    (aggregators may still accept it or return an error).
+
+    Examples::
+
+        >>> _prepend_vendor("claude-sonnet-4.6")
+        'anthropic/claude-sonnet-4.6'
+        >>> _prepend_vendor("anthropic/claude-sonnet-4.6")
+        'anthropic/claude-sonnet-4.6'
+        >>> _prepend_vendor("my-custom-thing")
+        'my-custom-thing'
+    """
+    if "/" in model_name:
+        return model_name
+
+    vendor = detect_vendor(model_name)
+    if vendor:
+        return f"{vendor}/{model_name}"
+    return model_name
+
+
+# ---------------------------------------------------------------------------
+# Main normalisation entry point
+# ---------------------------------------------------------------------------
+
+def normalize_model_for_provider(model_input: str, target_provider: str) -> str:
+    """Translate a model name into the format the target provider's API expects.
+
+    This is the primary entry point for model name normalisation.  It
+    accepts any user-facing model identifier and transforms it for the
+    specific provider that will receive the API call.
+
+    Args:
+        model_input: The model name as provided by the user or config.
+            Can be bare (``"claude-sonnet-4.6"``), vendor-prefixed
+            (``"anthropic/claude-sonnet-4.6"``), or already in native
+            format (``"claude-sonnet-4-6"``).
+        target_provider: The canonical Hermes provider id, e.g.
+            ``"openrouter"``, ``"anthropic"``, ``"copilot"``,
+            ``"deepseek"``, ``"custom"``.  Should already be normalised
+            via ``hermes_cli.models.normalize_provider()``.
+
+    Returns:
+        The model identifier string that the target provider's API
+        expects.
+
+    Raises:
+        No exceptions -- always returns a best-effort string.
+
+    Examples::
+
+        >>> normalize_model_for_provider("claude-sonnet-4.6", "openrouter")
+        'anthropic/claude-sonnet-4.6'
+
+        >>> normalize_model_for_provider("anthropic/claude-sonnet-4.6", "anthropic")
+        'claude-sonnet-4-6'
+
+        >>> normalize_model_for_provider("anthropic/claude-sonnet-4.6", "copilot")
+        'claude-sonnet-4.6'
+
+        >>> normalize_model_for_provider("openai/gpt-5.4", "copilot")
+        'gpt-5.4'
+
+        >>> normalize_model_for_provider("claude-sonnet-4.6", "opencode-zen")
+        'claude-sonnet-4-6'
+
+        >>> normalize_model_for_provider("deepseek-v3", "deepseek")
+        'deepseek-chat'
+
+        >>> normalize_model_for_provider("deepseek-r1", "deepseek")
+        'deepseek-reasoner'
+
+        >>> normalize_model_for_provider("my-model", "custom")
+        'my-model'
+
+        >>> normalize_model_for_provider("claude-sonnet-4.6", "zai")
+        'claude-sonnet-4.6'
+    """
+    name = (model_input or "").strip()
+    if not name:
+        return name
+
+    provider = (target_provider or "").strip().lower()
+
+    # --- Aggregators: need vendor/model format ---
+    if provider in _AGGREGATOR_PROVIDERS:
+        return _prepend_vendor(name)
+
+    # --- Anthropic / OpenCode: strip vendor, dots -> hyphens ---
+    if provider in _DOT_TO_HYPHEN_PROVIDERS:
+        bare = _strip_vendor_prefix(name)
+        return _dots_to_hyphens(bare)
+
+    # --- Copilot: strip vendor, keep dots ---
+    if provider in _STRIP_VENDOR_ONLY_PROVIDERS:
+        return _strip_vendor_prefix(name)
+
+    # --- DeepSeek: map to one of two canonical names ---
+    if provider == "deepseek":
+        return _normalize_for_deepseek(name)
+
+    # --- Custom & all others: pass through as-is ---
+    return name
+
+
+# ---------------------------------------------------------------------------
+# Batch / convenience helpers
+# ---------------------------------------------------------------------------
+
+def model_display_name(model_id: str) -> str:
+    """Return a short, human-readable display name for a model id.
+
+    Strips the vendor prefix (if any) for a cleaner display in menus
+    and status bars, while preserving dots for readability.
+
+    Examples::
+
+        >>> model_display_name("anthropic/claude-sonnet-4.6")
+        'claude-sonnet-4.6'
+        >>> model_display_name("claude-sonnet-4-6")
+        'claude-sonnet-4-6'
+    """
+    return _strip_vendor_prefix((model_id or "").strip())
+
+
+def is_aggregator_provider(provider: str) -> bool:
+    """Check if a provider is an aggregator that needs vendor/model format."""
+    return (provider or "").strip().lower() in _AGGREGATOR_PROVIDERS
+
+
+def vendor_for_model(model_name: str) -> str:
+    """Return the vendor slug for a model, or ``""`` if unknown.
+
+    Convenience wrapper around :func:`detect_vendor` that never returns
+    ``None``.
+    """
+    return detect_vendor(model_name) or ""

hermes_cli/model_switch.py

@@ -3,18 +3,120 @@
 Both the CLI (cli.py) and gateway (gateway/run.py) /model handlers
 share the same core pipeline:
 
-  parse_model_input → is_custom detection → auto-detect provider
-  → credential resolution → validate model → return result
+  parse flags -> alias resolution -> provider resolution ->
+  credential resolution -> normalize model name ->
+  metadata lookup -> build result
 
-This module extracts that shared pipeline into pure functions that
-return result objects. The callers handle all platform-specific
-concerns: state mutation, config persistence, output formatting.
+This module ties together the foundation layers:
+
+- ``agent.models_dev``            -- models.dev catalog, ModelInfo, ProviderInfo
+- ``hermes_cli.providers``        -- canonical provider identity + overlays
+- ``hermes_cli.model_normalize``  -- per-provider name formatting
+
+Provider switching uses the ``--provider`` flag exclusively.
+No colon-based ``provider:model`` syntax — colons are reserved for
+OpenRouter variant suffixes (``:free``, ``:extended``, ``:fast``).
 """
 
 from __future__ import annotations
 
-from dataclasses import dataclass
+import logging
+from dataclasses import dataclass, field
+from typing import List, NamedTuple, Optional
 
+from hermes_cli.providers import (
+    ALIASES,
+    LABELS,
+    TRANSPORT_TO_API_MODE,
+    determine_api_mode,
+    get_label,
+    get_provider,
+    is_aggregator,
+    normalize_provider,
+    resolve_provider_full,
+)
+from hermes_cli.model_normalize import (
+    detect_vendor,
+    normalize_model_for_provider,
+)
+from agent.models_dev import (
+    ModelCapabilities,
+    ModelInfo,
+    get_model_capabilities,
+    get_model_info,
+    list_provider_models,
+    search_models_dev,
+)
+
+logger = logging.getLogger(__name__)
+
+
+# ---------------------------------------------------------------------------
+# Model aliases -- short names -> (vendor, family) with NO version numbers.
+# Resolved dynamically against the live models.dev catalog.
+# ---------------------------------------------------------------------------
+
+class ModelIdentity(NamedTuple):
+    """Vendor slug and family prefix used for catalog resolution."""
+    vendor: str
+    family: str
+
+
+MODEL_ALIASES: dict[str, ModelIdentity] = {
+    # Anthropic
+    "sonnet":    ModelIdentity("anthropic", "claude-sonnet"),
+    "opus":      ModelIdentity("anthropic", "claude-opus"),
+    "haiku":     ModelIdentity("anthropic", "claude-haiku"),
+    "claude":    ModelIdentity("anthropic", "claude"),
+
+    # OpenAI
+    "gpt5":      ModelIdentity("openai", "gpt-5"),
+    "gpt":       ModelIdentity("openai", "gpt"),
+    "codex":     ModelIdentity("openai", "codex"),
+    "o3":        ModelIdentity("openai", "o3"),
+    "o4":        ModelIdentity("openai", "o4"),
+
+    # Google
+    "gemini":    ModelIdentity("google", "gemini"),
+
+    # DeepSeek
+    "deepseek":  ModelIdentity("deepseek", "deepseek-chat"),
+
+    # X.AI
+    "grok":      ModelIdentity("x-ai", "grok"),
+
+    # Meta
+    "llama":     ModelIdentity("meta-llama", "llama"),
+
+    # Qwen / Alibaba
+    "qwen":      ModelIdentity("qwen", "qwen"),
+
+    # MiniMax
+    "minimax":   ModelIdentity("minimax", "minimax"),
+
+    # Nvidia
+    "nemotron":  ModelIdentity("nvidia", "nemotron"),
+
+    # Moonshot / Kimi
+    "kimi":      ModelIdentity("moonshotai", "kimi"),
+
+    # Z.AI / GLM
+    "glm":       ModelIdentity("z-ai", "glm"),
+
+    # StepFun
+    "step":      ModelIdentity("stepfun", "step"),
+
+    # Xiaomi
+    "mimo":      ModelIdentity("xiaomi", "mimo"),
+
+    # Arcee
+    "trinity":   ModelIdentity("arcee-ai", "trinity"),
+}
+
+
+# ---------------------------------------------------------------------------
+# Result dataclasses
+# ---------------------------------------------------------------------------
 
 @dataclass
 class ModelSwitchResult:
@@ -27,11 +129,13 @@ class ModelSwitchResult:
     api_key: str = ""
     base_url: str = ""
     api_mode: str = ""
-    persist: bool = False
     error_message: str = ""
     warning_message: str = ""
-    is_custom_target: bool = False
     provider_label: str = ""
+    resolved_via_alias: str = ""
+    capabilities: Optional[ModelCapabilities] = None
+    model_info: Optional[ModelInfo] = None
+    is_global: bool = False
 
 
 @dataclass
@@ -45,91 +149,336 @@ class CustomAutoResult:
     error_message: str = ""
 
 
+# ---------------------------------------------------------------------------
+# Flag parsing
+# ---------------------------------------------------------------------------
+
+def parse_model_flags(raw_args: str) -> tuple[str, str, bool]:
+    """Parse --provider and --global flags from /model command args.
+
+    Returns (model_input, explicit_provider, is_global).
+
+    Examples::
+
+        "sonnet"                         -> ("sonnet", "", False)
+        "sonnet --global"                -> ("sonnet", "", True)
+        "sonnet --provider anthropic"    -> ("sonnet", "anthropic", False)
+        "--provider my-ollama"           -> ("", "my-ollama", False)
+        "sonnet --provider anthropic --global" -> ("sonnet", "anthropic", True)
+    """
+    is_global = False
+    explicit_provider = ""
+
+    # Extract --global
+    if "--global" in raw_args:
+        is_global = True
+        raw_args = raw_args.replace("--global", "").strip()
+
+    # Extract --provider <name>
+    parts = raw_args.split()
+    i = 0
+    filtered: list[str] = []
+    while i < len(parts):
+        if parts[i] == "--provider" and i + 1 < len(parts):
+            explicit_provider = parts[i + 1]
+            i += 2
+        else:
+            filtered.append(parts[i])
+            i += 1
+
+    model_input = " ".join(filtered).strip()
+    return (model_input, explicit_provider, is_global)
+
+
+# ---------------------------------------------------------------------------
+# Alias resolution
+# ---------------------------------------------------------------------------
+
+def resolve_alias(
+    raw_input: str,
+    current_provider: str,
+) -> Optional[tuple[str, str, str]]:
+    """Resolve a short alias against the current provider's catalog.
+
+    Looks up *raw_input* in :data:`MODEL_ALIASES`, then searches the
+    current provider's models.dev catalog for the first model whose ID
+    starts with ``vendor/family`` (or just ``family`` for non-aggregator
+    providers).
+
+    Returns:
+        ``(provider, resolved_model_id, alias_name)`` if a match is
+        found on the current provider, or ``None`` if the alias doesn't
+        exist or no matching model is available.
+    """
+    key = raw_input.strip().lower()
+    identity = MODEL_ALIASES.get(key)
+    if identity is None:
+        return None
+
+    vendor, family = identity
+
+    # Search the provider's catalog from models.dev
+    catalog = list_provider_models(current_provider)
+    if not catalog:
+        return None
+
+    # For aggregators, models are vendor/model-name format
+    aggregator = is_aggregator(current_provider)
+
+    for model_id in catalog:
+        mid_lower = model_id.lower()
+        if aggregator:
+            # Match vendor/family prefix -- e.g. "anthropic/claude-sonnet"
+            prefix = f"{vendor}/{family}".lower()
+            if mid_lower.startswith(prefix):
+                return (current_provider, model_id, key)
+        else:
+            # Non-aggregator: bare names -- e.g. "claude-sonnet-4-6"
+            family_lower = family.lower()
+            if mid_lower.startswith(family_lower):
+                return (current_provider, model_id, key)
+
+    return None
+
+
+def _resolve_alias_fallback(
+    raw_input: str,
+    fallback_providers: tuple[str, ...] = ("openrouter", "nous"),
+) -> Optional[tuple[str, str, str]]:
+    """Try to resolve an alias on fallback providers."""
+    for provider in fallback_providers:
+        result = resolve_alias(raw_input, provider)
+        if result is not None:
+            return result
+    return None
+
+
+# ---------------------------------------------------------------------------
+# Core model-switching pipeline
+# ---------------------------------------------------------------------------
+
 def switch_model(
     raw_input: str,
     current_provider: str,
+    current_model: str,
     current_base_url: str = "",
     current_api_key: str = "",
+    is_global: bool = False,
+    explicit_provider: str = "",
+    user_providers: dict = None,
 ) -> ModelSwitchResult:
     """Core model-switching pipeline shared between CLI and gateway.
 
-    Handles parsing, provider detection, credential resolution, and
-    model validation.  Does NOT handle config persistence, state
-    mutation, or output formatting — those are caller responsibilities.
+    Resolution chain:
+
+      If --provider given:
+        a. Resolve provider via resolve_provider_full()
+        b. Resolve credentials
+        c. If model given, resolve alias on target provider or use as-is
+        d. If no model, auto-detect from endpoint
+
+      If no --provider:
+        a. Try alias resolution on current provider
+        b. If alias exists but not on current provider -> fallback
+        c. On aggregator, try vendor/model slug conversion
+        d. Aggregator catalog search
+        e. detect_provider_for_model() as last resort
+        f. Resolve credentials
+        g. Normalize model name for target provider
+
+      Finally:
+        h. Get full model metadata from models.dev
+        i. Build result
 
     Args:
-        raw_input: The user's model input (e.g. "claude-sonnet-4",
-            "zai:glm-5", "custom:local:qwen").
+        raw_input: The model name (after flag parsing).
         current_provider: The currently active provider.
-        current_base_url: The currently active base URL (used for
-            is_custom detection).
+        current_model: The currently active model name.
+        current_base_url: The currently active base URL.
         current_api_key: The currently active API key.
+        is_global: Whether to persist the switch.
+        explicit_provider: From --provider flag (empty = no explicit provider).
+        user_providers: The ``providers:`` dict from config.yaml (for user endpoints).
 
     Returns:
-        ModelSwitchResult with all information the caller needs to
-        apply the switch and format output.
+        ModelSwitchResult with all information the caller needs.
     """
     from hermes_cli.models import (
-        parse_model_input,
         detect_provider_for_model,
         validate_requested_model,
-        _PROVIDER_LABELS,
         opencode_model_api_mode,
     )
     from hermes_cli.runtime_provider import resolve_runtime_provider
 
-    # Step 1: Parse provider:model syntax
-    target_provider, new_model = parse_model_input(raw_input, current_provider)
+    resolved_alias = ""
+    new_model = raw_input.strip()
+    target_provider = current_provider
 
-    # Step 2: Detect if we're currently on a custom endpoint
-    _base = current_base_url or ""
-    is_custom = current_provider == "custom" or (
-        "localhost" in _base or "127.0.0.1" in _base
-    )
+    # =================================================================
+    # PATH A: Explicit --provider given
+    # =================================================================
+    if explicit_provider:
+        # Resolve the provider
+        pdef = resolve_provider_full(explicit_provider, user_providers)
+        if pdef is None:
+            return ModelSwitchResult(
+                success=False,
+                is_global=is_global,
+                error_message=(
+                    f"Unknown provider '{explicit_provider}'. "
+                    f"Check 'hermes model' for available providers, or define it "
+                    f"in config.yaml under 'providers:'."
+                ),
+            )
 
-    # Step 3: Auto-detect provider when no explicit provider:model syntax
-    # was used.  Skip for custom providers — the model name might
-    # coincidentally match a known provider's catalog.
-    if target_provider == current_provider and not is_custom:
-        detected = detect_provider_for_model(new_model, current_provider)
-        if detected:
-            target_provider, new_model = detected
+        target_provider = pdef.id
+
+        # If no model specified, try auto-detect from endpoint
+        if not new_model:
+            if pdef.base_url:
+                from hermes_cli.runtime_provider import _auto_detect_local_model
+                detected = _auto_detect_local_model(pdef.base_url)
+                if detected:
+                    new_model = detected
+                else:
+                    return ModelSwitchResult(
+                        success=False,
+                        target_provider=target_provider,
+                        provider_label=pdef.name,
+                        is_global=is_global,
+                        error_message=(
+                            f"No model detected on {pdef.name} ({pdef.base_url}). "
+                            f"Specify the model explicitly: /model <model-name> --provider {explicit_provider}"
+                        ),
+                    )
+            else:
+                return ModelSwitchResult(
+                    success=False,
+                    target_provider=target_provider,
+                    provider_label=pdef.name,
+                    is_global=is_global,
+                    error_message=(
+                        f"Provider '{pdef.name}' has no base URL configured. "
+                        f"Specify a model: /model <model-name> --provider {explicit_provider}"
+                    ),
+                )
+
+        # Resolve alias on the TARGET provider
+        alias_result = resolve_alias(new_model, target_provider)
+        if alias_result is not None:
+            _, new_model, resolved_alias = alias_result
+
+    # =================================================================
+    # PATH B: No explicit provider — resolve from model input
+    # =================================================================
+    else:
+        # --- Step a: Try alias resolution on current provider ---
+        alias_result = resolve_alias(raw_input, current_provider)
+
+        if alias_result is not None:
+            target_provider, new_model, resolved_alias = alias_result
+            logger.debug(
+                "Alias '%s' resolved to %s on %s",
+                resolved_alias, new_model, target_provider,
+            )
+        else:
+            # --- Step b: Alias exists but not on current provider -> fallback ---
+            key = raw_input.strip().lower()
+            if key in MODEL_ALIASES:
+                fallback_result = _resolve_alias_fallback(raw_input)
+                if fallback_result is not None:
+                    target_provider, new_model, resolved_alias = fallback_result
+                    logger.debug(
+                        "Alias '%s' resolved via fallback to %s on %s",
+                        resolved_alias, new_model, target_provider,
+                    )
+                else:
+                    identity = MODEL_ALIASES[key]
+                    return ModelSwitchResult(
+                        success=False,
+                        is_global=is_global,
+                        error_message=(
+                            f"Alias '{key}' maps to {identity.vendor}/{identity.family} "
+                            f"but no matching model was found in any provider catalog. "
+                            f"Try specifying the full model name."
+                        ),
+                    )
+            else:
+                # --- Step c: On aggregator, convert vendor:model to vendor/model ---
+                colon_pos = raw_input.find(":")
+                if colon_pos > 0 and is_aggregator(current_provider):
+                    left = raw_input[:colon_pos].strip().lower()
+                    right = raw_input[colon_pos + 1:].strip()
+                    if left and right:
+                        # Colons become slashes for aggregator slugs
+                        new_model = f"{left}/{right}"
+                        logger.debug(
+                            "Converted vendor:model '%s' to aggregator slug '%s'",
+                            raw_input, new_model,
+                        )
+
+        # --- Step d: Aggregator catalog search ---
+        if is_aggregator(target_provider) and not resolved_alias:
+            catalog = list_provider_models(target_provider)
+            if catalog:
+                new_model_lower = new_model.lower()
+                for mid in catalog:
+                    if mid.lower() == new_model_lower:
+                        new_model = mid
+                        break
+                else:
+                    for mid in catalog:
+                        if "/" in mid:
+                            _, bare = mid.split("/", 1)
+                            if bare.lower() == new_model_lower:
+                                new_model = mid
+                                break
+
+        # --- Step e: detect_provider_for_model() as last resort ---
+        _base = current_base_url or ""
+        is_custom = current_provider in ("custom", "local") or (
+            "localhost" in _base or "127.0.0.1" in _base
+        )
+
+        if (
+            target_provider == current_provider
+            and not is_custom
+            and not resolved_alias
+        ):
+            detected = detect_provider_for_model(new_model, current_provider)
+            if detected:
+                target_provider, new_model = detected
+
+    # =================================================================
+    # COMMON PATH: Resolve credentials, normalize, get metadata
+    # =================================================================
 
     provider_changed = target_provider != current_provider
+    provider_label = get_label(target_provider)
 
-    # Step 4: Resolve credentials for target provider
+    # --- Resolve credentials ---
     api_key = current_api_key
     base_url = current_base_url
     api_mode = ""
-    if provider_changed:
+
+    if provider_changed or explicit_provider:
         try:
             runtime = resolve_runtime_provider(requested=target_provider)
             api_key = runtime.get("api_key", "")
             base_url = runtime.get("base_url", "")
             api_mode = runtime.get("api_mode", "")
         except Exception as e:
-            provider_label = _PROVIDER_LABELS.get(target_provider, target_provider)
-            if target_provider == "custom":
-                return ModelSwitchResult(
-                    success=False,
-                    target_provider=target_provider,
-                    error_message=(
-                        "No custom endpoint configured. Set model.base_url "
-                        "in config.yaml, or set OPENAI_BASE_URL in .env, "
-                        "or run: hermes setup → Custom OpenAI-compatible endpoint"
-                    ),
-                )
             return ModelSwitchResult(
                 success=False,
                 target_provider=target_provider,
+                provider_label=provider_label,
+                is_global=is_global,
                 error_message=(
                     f"Could not resolve credentials for provider "
                     f"'{provider_label}': {e}"
                 ),
             )
     else:
-        # Gateway also resolves for unchanged provider to get accurate
-        # base_url for validation probing.
         try:
             runtime = resolve_runtime_provider(requested=current_provider)
             api_key = runtime.get("api_key", "")
@@ -138,7 +487,10 @@ def switch_model(
         except Exception:
             pass
 
-    # Step 5: Validate the model
+    # --- Normalize model name for target provider ---
+    new_model = normalize_model_for_provider(new_model, target_provider)
+
+    # --- Validate ---
     try:
         validation = validate_requested_model(
             new_model,
@@ -160,23 +512,26 @@ def switch_model(
             success=False,
             new_model=new_model,
             target_provider=target_provider,
+            provider_label=provider_label,
+            is_global=is_global,
             error_message=msg,
         )
 
-    # Step 6: Build result
-    provider_label = _PROVIDER_LABELS.get(target_provider, target_provider)
-    is_custom_target = target_provider == "custom" or (
-        base_url
-        and "openrouter.ai" not in (base_url or "")
-        and ("localhost" in (base_url or "") or "127.0.0.1" in (base_url or ""))
-    )
-
-    if target_provider in {"opencode-zen", "opencode-go"}:
-        # Recompute against the requested new model, not the currently-configured
-        # model used during runtime resolution. OpenCode mixes API surfaces by
-        # model family, so a same-provider model switch can change api_mode.
+    # --- OpenCode api_mode override ---
+    if target_provider in {"opencode-zen", "opencode-go", "opencode", "opencode-go"}:
         api_mode = opencode_model_api_mode(target_provider, new_model)
 
+    # --- Determine api_mode if not already set ---
+    if not api_mode:
+        api_mode = determine_api_mode(target_provider, base_url)
+
+    # --- Get capabilities (legacy) ---
+    capabilities = get_model_capabilities(target_provider, new_model)
+
+    # --- Get full model info from models.dev ---
+    model_info = get_model_info(target_provider, new_model)
+
+    # --- Build result ---
     return ModelSwitchResult(
         success=True,
         new_model=new_model,
@@ -185,18 +540,191 @@ def switch_model(
         api_key=api_key,
         base_url=base_url,
         api_mode=api_mode,
-        persist=bool(validation.get("persist")),
         warning_message=validation.get("message") or "",
-        is_custom_target=is_custom_target,
         provider_label=provider_label,
+        resolved_via_alias=resolved_alias,
+        capabilities=capabilities,
+        model_info=model_info,
+        is_global=is_global,
     )
 
 
-def switch_to_custom_provider() -> CustomAutoResult:
-    """Handle bare '/model custom' — resolve endpoint and auto-detect model.
+# ---------------------------------------------------------------------------
+# Authenticated providers listing (for /model no-args display)
+# ---------------------------------------------------------------------------
 
-    Returns a result object; the caller handles persistence and output.
+def list_authenticated_providers(
+    current_provider: str = "",
+    user_providers: dict = None,
+    max_models: int = 8,
+) -> List[dict]:
+    """Detect which providers have credentials and list their curated models.
+
+    Uses the curated model lists from hermes_cli/models.py (OPENROUTER_MODELS,
+    _PROVIDER_MODELS) — NOT the full models.dev catalog.  These are hand-picked
+    agentic models that work well as agent backends.
+
+    Returns a list of dicts, each with:
+      - slug: str — the --provider value to use
+      - name: str — display name
+      - is_current: bool
+      - is_user_defined: bool
+      - models: list[str] — curated model IDs (up to max_models)
+      - total_models: int — total curated count
+      - source: str — "built-in", "models.dev", "user-config"
+
+    Only includes providers that have API keys set or are user-defined endpoints.
     """
+    import os
+    from agent.models_dev import (
+        PROVIDER_TO_MODELS_DEV,
+        fetch_models_dev,
+        get_provider_info as _mdev_pinfo,
+    )
+    from hermes_cli.models import OPENROUTER_MODELS, _PROVIDER_MODELS
+
+    results: List[dict] = []
+    seen_slugs: set = set()
+
+    data = fetch_models_dev()
+
+    # Build curated model lists keyed by hermes provider ID
+    curated: dict[str, list[str]] = dict(_PROVIDER_MODELS)
+    curated["openrouter"] = [mid for mid, _ in OPENROUTER_MODELS]
+    # "nous" shares OpenRouter's curated list if not separately defined
+    if "nous" not in curated:
+        curated["nous"] = curated["openrouter"]
+
+    # --- 1. Check Hermes-mapped providers ---
+    for hermes_id, mdev_id in PROVIDER_TO_MODELS_DEV.items():
+        pdata = data.get(mdev_id)
+        if not isinstance(pdata, dict):
+            continue
+
+        env_vars = pdata.get("env", [])
+        if not isinstance(env_vars, list):
+            continue
+
+        # Check if any env var is set
+        has_creds = any(os.environ.get(ev) for ev in env_vars)
+        if not has_creds:
+            continue
+
+        # Use curated list, falling back to models.dev if no curated list
+        model_ids = curated.get(hermes_id, [])
+        total = len(model_ids)
+        top = model_ids[:max_models]
+
+        slug = hermes_id
+        pinfo = _mdev_pinfo(mdev_id)
+        display_name = pinfo.name if pinfo else mdev_id
+
+        results.append({
+            "slug": slug,
+            "name": display_name,
+            "is_current": slug == current_provider or mdev_id == current_provider,
+            "is_user_defined": False,
+            "models": top,
+            "total_models": total,
+            "source": "built-in",
+        })
+        seen_slugs.add(slug)
+
+    # --- 2. Check Hermes-only providers (nous, openai-codex, copilot) ---
+    from hermes_cli.providers import HERMES_OVERLAYS
+    for pid, overlay in HERMES_OVERLAYS.items():
+        if pid in seen_slugs:
+            continue
+        # Check if credentials exist
+        has_creds = False
+        if overlay.extra_env_vars:
+            has_creds = any(os.environ.get(ev) for ev in overlay.extra_env_vars)
+        if overlay.auth_type in ("oauth_device_code", "oauth_external", "external_process"):
+            # These use auth stores, not env vars — check for auth.json entries
+            try:
+                from hermes_cli.auth import _read_auth_store
+                store = _read_auth_store()
+                if store and pid in store:
+                    has_creds = True
+            except Exception:
+                pass
+        if not has_creds:
+            continue
+
+        # Use curated list
+        model_ids = curated.get(pid, [])
+        total = len(model_ids)
+        top = model_ids[:max_models]
+
+        results.append({
+            "slug": pid,
+            "name": get_label(pid),
+            "is_current": pid == current_provider,
+            "is_user_defined": False,
+            "models": top,
+            "total_models": total,
+            "source": "hermes",
+        })
+        seen_slugs.add(pid)
+
+    # --- 3. User-defined endpoints from config ---
+    if user_providers and isinstance(user_providers, dict):
+        for ep_name, ep_cfg in user_providers.items():
+            if not isinstance(ep_cfg, dict):
+                continue
+            display_name = ep_cfg.get("name", "") or ep_name
+            api_url = ep_cfg.get("api", "") or ep_cfg.get("url", "") or ""
+            default_model = ep_cfg.get("default_model", "")
+
+            models_list = []
+            if default_model:
+                models_list.append(default_model)
+
+            # Try to probe /v1/models if URL is set (but don't block on it)
+            # For now just show what we know from config
+            results.append({
+                "slug": ep_name,
+                "name": display_name,
+                "is_current": ep_name == current_provider,
+                "is_user_defined": True,
+                "models": models_list,
+                "total_models": len(models_list) if models_list else 0,
+                "source": "user-config",
+                "api_url": api_url,
+            })
+
+    # Sort: current provider first, then by model count descending
+    results.sort(key=lambda r: (not r["is_current"], -r["total_models"]))
+
+    return results
+
+
+# ---------------------------------------------------------------------------
+# Fuzzy suggestions
+# ---------------------------------------------------------------------------
+
+def suggest_models(raw_input: str, limit: int = 3) -> List[str]:
+    """Return fuzzy model suggestions for a (possibly misspelled) input."""
+    query = raw_input.strip()
+    if not query:
+        return []
+
+    results = search_models_dev(query, limit=limit)
+    suggestions: list[str] = []
+    for r in results:
+        mid = r.get("model_id", "")
+        if mid:
+            suggestions.append(mid)
+
+    return suggestions[:limit]
+
+
+# ---------------------------------------------------------------------------
+# Custom provider switch
+# ---------------------------------------------------------------------------
+
+def switch_to_custom_provider() -> CustomAutoResult:
+    """Handle bare '/model --provider custom' — resolve endpoint and auto-detect model."""
     from hermes_cli.runtime_provider import (
         resolve_runtime_provider,
         _auto_detect_local_model,
@@ -219,7 +747,7 @@ def switch_to_custom_provider() -> CustomAutoResult:
             error_message=(
                 "No custom endpoint configured. "
                 "Set model.base_url in config.yaml, or set OPENAI_BASE_URL "
-                "in .env, or run: hermes setup → Custom OpenAI-compatible endpoint"
+                "in .env, or run: hermes setup -> Custom OpenAI-compatible endpoint"
             ),
         )
 
@@ -232,7 +760,7 @@ def switch_to_custom_provider() -> CustomAutoResult:
             error_message=(
                 f"Custom endpoint at {cust_base} is reachable but no single "
                 f"model was auto-detected. Specify the model explicitly: "
-                f"/model custom:<model-name>"
+                f"/model <model-name> --provider custom"
             ),
         )
 

hermes_cli/providers.py

@@ -0,0 +1,519 @@
+"""
+Single source of truth for provider identity in Hermes Agent.
+
+Two data sources, merged at runtime:
+
+1. **models.dev catalog** — 109+ providers with base URLs, env vars, display
+   names, and full model metadata (context, cost, capabilities).  This is
+   the primary database.
+
+2. **Hermes overlays** — transport type, auth patterns, aggregator flags,
+   and additional env vars that models.dev doesn't track.  Small dict,
+   maintained here.
+
+3. **User config** (``providers:`` section in config.yaml) — user-defined
+   endpoints and overrides.  Merged on top of everything else.
+
+Other modules import from this file.  No parallel registries.
+"""
+
+from __future__ import annotations
+
+import logging
+import os
+from dataclasses import dataclass, field
+from typing import Any, Dict, List, Optional, Tuple
+
+logger = logging.getLogger(__name__)
+
+
+# -- Hermes overlay ----------------------------------------------------------
+# Hermes-specific metadata that models.dev doesn't provide.
+
+@dataclass(frozen=True)
+class HermesOverlay:
+    """Hermes-specific provider metadata layered on top of models.dev."""
+
+    transport: str = "openai_chat"        # openai_chat | anthropic_messages | codex_responses
+    is_aggregator: bool = False
+    auth_type: str = "api_key"            # api_key | oauth_device_code | oauth_external | external_process
+    extra_env_vars: Tuple[str, ...] = ()  # env vars models.dev doesn't list
+    base_url_override: str = ""           # override if models.dev URL is wrong/missing
+    base_url_env_var: str = ""            # env var for user-custom base URL
+
+
+HERMES_OVERLAYS: Dict[str, HermesOverlay] = {
+    "openrouter": HermesOverlay(
+        transport="openai_chat",
+        is_aggregator=True,
+        extra_env_vars=("OPENAI_API_KEY",),
+        base_url_env_var="OPENROUTER_BASE_URL",
+    ),
+    "nous": HermesOverlay(
+        transport="openai_chat",
+        auth_type="oauth_device_code",
+        base_url_override="https://inference-api.nousresearch.com/v1",
+    ),
+    "openai-codex": HermesOverlay(
+        transport="codex_responses",
+        auth_type="oauth_external",
+        base_url_override="https://chatgpt.com/backend-api/codex",
+    ),
+    "copilot-acp": HermesOverlay(
+        transport="codex_responses",
+        auth_type="external_process",
+        base_url_override="acp://copilot",
+        base_url_env_var="COPILOT_ACP_BASE_URL",
+    ),
+    "github-copilot": HermesOverlay(
+        transport="openai_chat",
+        extra_env_vars=("COPILOT_GITHUB_TOKEN", "GH_TOKEN"),
+    ),
+    "anthropic": HermesOverlay(
+        transport="anthropic_messages",
+        extra_env_vars=("ANTHROPIC_TOKEN", "CLAUDE_CODE_OAUTH_TOKEN"),
+    ),
+    "zai": HermesOverlay(
+        transport="openai_chat",
+        extra_env_vars=("GLM_API_KEY", "ZAI_API_KEY", "Z_AI_API_KEY"),
+        base_url_env_var="GLM_BASE_URL",
+    ),
+    "kimi-for-coding": HermesOverlay(
+        transport="openai_chat",
+        base_url_env_var="KIMI_BASE_URL",
+    ),
+    "minimax": HermesOverlay(
+        transport="openai_chat",
+        base_url_env_var="MINIMAX_BASE_URL",
+    ),
+    "minimax-cn": HermesOverlay(
+        transport="openai_chat",
+        base_url_env_var="MINIMAX_CN_BASE_URL",
+    ),
+    "deepseek": HermesOverlay(
+        transport="openai_chat",
+        base_url_env_var="DEEPSEEK_BASE_URL",
+    ),
+    "alibaba": HermesOverlay(
+        transport="openai_chat",
+        base_url_env_var="DASHSCOPE_BASE_URL",
+    ),
+    "vercel": HermesOverlay(
+        transport="openai_chat",
+        is_aggregator=True,
+    ),
+    "opencode": HermesOverlay(
+        transport="openai_chat",
+        is_aggregator=True,
+        base_url_env_var="OPENCODE_ZEN_BASE_URL",
+    ),
+    "opencode-go": HermesOverlay(
+        transport="openai_chat",
+        is_aggregator=True,
+        base_url_env_var="OPENCODE_GO_BASE_URL",
+    ),
+    "kilo": HermesOverlay(
+        transport="openai_chat",
+        is_aggregator=True,
+        base_url_env_var="KILOCODE_BASE_URL",
+    ),
+    "huggingface": HermesOverlay(
+        transport="openai_chat",
+        is_aggregator=True,
+        base_url_env_var="HF_BASE_URL",
+    ),
+}
+
+
+# -- Resolved provider -------------------------------------------------------
+# The merged result of models.dev + overlay + user config.
+
+@dataclass
+class ProviderDef:
+    """Complete provider definition — merged from all sources."""
+
+    id: str
+    name: str
+    transport: str                        # openai_chat | anthropic_messages | codex_responses
+    api_key_env_vars: Tuple[str, ...]     # all env vars to check for API key
+    base_url: str = ""
+    base_url_env_var: str = ""
+    is_aggregator: bool = False
+    auth_type: str = "api_key"
+    doc: str = ""
+    source: str = ""                      # "models.dev", "hermes", "user-config"
+
+    @property
+    def is_user_defined(self) -> bool:
+        return self.source == "user-config"
+
+
+# -- Aliases ------------------------------------------------------------------
+# Maps human-friendly / legacy names to canonical provider IDs.
+# Uses models.dev IDs where possible.
+
+ALIASES: Dict[str, str] = {
+    # openrouter
+    "openai": "openrouter",     # bare "openai" → route through aggregator
+
+    # zai
+    "glm": "zai",
+    "z-ai": "zai",
+    "z.ai": "zai",
+    "zhipu": "zai",
+
+    # kimi-for-coding (models.dev ID)
+    "kimi": "kimi-for-coding",
+    "kimi-coding": "kimi-for-coding",
+    "moonshot": "kimi-for-coding",
+
+    # minimax-cn
+    "minimax-china": "minimax-cn",
+    "minimax_cn": "minimax-cn",
+
+    # anthropic
+    "claude": "anthropic",
+    "claude-code": "anthropic",
+
+    # github-copilot (models.dev ID)
+    "copilot": "github-copilot",
+    "github": "github-copilot",
+    "github-copilot-acp": "copilot-acp",
+
+    # vercel (models.dev ID for AI Gateway)
+    "ai-gateway": "vercel",
+    "aigateway": "vercel",
+    "vercel-ai-gateway": "vercel",
+
+    # opencode (models.dev ID for OpenCode Zen)
+    "opencode-zen": "opencode",
+    "zen": "opencode",
+
+    # opencode-go
+    "go": "opencode-go",
+    "opencode-go-sub": "opencode-go",
+
+    # kilo (models.dev ID for KiloCode)
+    "kilocode": "kilo",
+    "kilo-code": "kilo",
+    "kilo-gateway": "kilo",
+
+    # deepseek
+    "deep-seek": "deepseek",
+
+    # alibaba
+    "dashscope": "alibaba",
+    "aliyun": "alibaba",
+    "qwen": "alibaba",
+    "alibaba-cloud": "alibaba",
+
+    # huggingface
+    "hf": "huggingface",
+    "hugging-face": "huggingface",
+    "huggingface-hub": "huggingface",
+
+    # Local server aliases → virtual "local" concept (resolved via user config)
+    "lmstudio": "lmstudio",
+    "lm-studio": "lmstudio",
+    "lm_studio": "lmstudio",
+    "ollama": "ollama-cloud",
+    "vllm": "local",
+    "llamacpp": "local",
+    "llama.cpp": "local",
+    "llama-cpp": "local",
+}
+
+
+# -- Display labels -----------------------------------------------------------
+# Built dynamically from models.dev + overlays.  Fallback for providers
+# not in the catalog.
+
+_LABEL_OVERRIDES: Dict[str, str] = {
+    "nous": "Nous Portal",
+    "openai-codex": "OpenAI Codex",
+    "copilot-acp": "GitHub Copilot ACP",
+    "local": "Local endpoint",
+}
+
+
+# -- Transport → API mode mapping ---------------------------------------------
+
+TRANSPORT_TO_API_MODE: Dict[str, str] = {
+    "openai_chat": "chat_completions",
+    "anthropic_messages": "anthropic_messages",
+    "codex_responses": "codex_responses",
+}
+
+
+# -- Helper functions ---------------------------------------------------------
+
+def normalize_provider(name: str) -> str:
+    """Resolve aliases and normalise casing to a canonical provider id.
+
+    Returns the canonical id string.  Does *not* validate that the id
+    corresponds to a known provider.
+    """
+    key = name.strip().lower()
+    return ALIASES.get(key, key)
+
+
+def get_overlay(provider_id: str) -> Optional[HermesOverlay]:
+    """Get Hermes overlay for a provider, if one exists."""
+    canonical = normalize_provider(provider_id)
+    return HERMES_OVERLAYS.get(canonical)
+
+
+def get_provider(name: str) -> Optional[ProviderDef]:
+    """Look up a provider by id or alias, merging all data sources.
+
+    Resolution order:
+      1. Hermes overlays (for providers not in models.dev: nous, openai-codex, etc.)
+      2. models.dev catalog + Hermes overlay
+      3. User-defined providers from config (TODO: Phase 4)
+
+    Returns a fully-resolved ProviderDef or None.
+    """
+    canonical = normalize_provider(name)
+
+    # Try to get models.dev data
+    try:
+        from agent.models_dev import get_provider_info as _mdev_provider
+        mdev_info = _mdev_provider(canonical)
+    except Exception:
+        mdev_info = None
+
+    overlay = HERMES_OVERLAYS.get(canonical)
+
+    if mdev_info is not None:
+        # Merge models.dev + overlay
+        transport = overlay.transport if overlay else "openai_chat"
+        is_agg = overlay.is_aggregator if overlay else False
+        auth = overlay.auth_type if overlay else "api_key"
+        base_url_env = overlay.base_url_env_var if overlay else ""
+        base_url_override = overlay.base_url_override if overlay else ""
+
+        # Combine env vars: models.dev env + hermes extra
+        env_vars = list(mdev_info.env)
+        if overlay and overlay.extra_env_vars:
+            for ev in overlay.extra_env_vars:
+                if ev not in env_vars:
+                    env_vars.append(ev)
+
+        return ProviderDef(
+            id=canonical,
+            name=mdev_info.name,
+            transport=transport,
+            api_key_env_vars=tuple(env_vars),
+            base_url=base_url_override or mdev_info.api,
+            base_url_env_var=base_url_env,
+            is_aggregator=is_agg,
+            auth_type=auth,
+            doc=mdev_info.doc,
+            source="models.dev",
+        )
+
+    if overlay is not None:
+        # Hermes-only provider (not in models.dev)
+        return ProviderDef(
+            id=canonical,
+            name=_LABEL_OVERRIDES.get(canonical, canonical),
+            transport=overlay.transport,
+            api_key_env_vars=overlay.extra_env_vars,
+            base_url=overlay.base_url_override,
+            base_url_env_var=overlay.base_url_env_var,
+            is_aggregator=overlay.is_aggregator,
+            auth_type=overlay.auth_type,
+            source="hermes",
+        )
+
+    return None
+
+
+def get_label(provider_id: str) -> str:
+    """Get a human-readable display name for a provider."""
+    canonical = normalize_provider(provider_id)
+
+    # Check label overrides first
+    if canonical in _LABEL_OVERRIDES:
+        return _LABEL_OVERRIDES[canonical]
+
+    # Try models.dev
+    pdef = get_provider(canonical)
+    if pdef:
+        return pdef.name
+
+    return canonical
+
+
+# Build LABELS dict for backward compat
+def _build_labels() -> Dict[str, str]:
+    """Build labels dict from overlays + overrides. Lazy, cached."""
+    labels: Dict[str, str] = {}
+    for pid in HERMES_OVERLAYS:
+        labels[pid] = get_label(pid)
+    labels.update(_LABEL_OVERRIDES)
+    return labels
+
+# Lazy-built on first access
+_labels_cache: Optional[Dict[str, str]] = None
+
+@property
+def LABELS() -> Dict[str, str]:
+    """Backward-compatible labels dict."""
+    global _labels_cache
+    if _labels_cache is None:
+        _labels_cache = _build_labels()
+    return _labels_cache
+
+# For direct import compat, expose as module-level dict
+# Built on demand by get_label() calls
+LABELS: Dict[str, str] = {
+    # Static entries for backward compat — get_label() is the proper API
+    "openrouter": "OpenRouter",
+    "nous": "Nous Portal",
+    "openai-codex": "OpenAI Codex",
+    "copilot-acp": "GitHub Copilot ACP",
+    "github-copilot": "GitHub Copilot",
+    "anthropic": "Anthropic",
+    "zai": "Z.AI / GLM",
+    "kimi-for-coding": "Kimi / Moonshot",
+    "minimax": "MiniMax",
+    "minimax-cn": "MiniMax (China)",
+    "deepseek": "DeepSeek",
+    "alibaba": "Alibaba Cloud (DashScope)",
+    "vercel": "Vercel AI Gateway",
+    "opencode": "OpenCode Zen",
+    "opencode-go": "OpenCode Go",
+    "kilo": "Kilo Gateway",
+    "huggingface": "Hugging Face",
+    "local": "Local endpoint",
+    "custom": "Custom endpoint",
+    # Legacy Hermes IDs (point to same providers)
+    "ai-gateway": "Vercel AI Gateway",
+    "kilocode": "Kilo Gateway",
+    "copilot": "GitHub Copilot",
+    "kimi-coding": "Kimi / Moonshot",
+    "opencode-zen": "OpenCode Zen",
+}
+
+
+def is_aggregator(provider: str) -> bool:
+    """Return True when the provider is a multi-model aggregator."""
+    pdef = get_provider(provider)
+    return pdef.is_aggregator if pdef else False
+
+
+def determine_api_mode(provider: str, base_url: str = "") -> str:
+    """Determine the API mode (wire protocol) for a provider/endpoint.
+
+    Resolution order:
+      1. Known provider → transport → TRANSPORT_TO_API_MODE.
+      2. URL heuristics for unknown / custom providers.
+      3. Default: 'chat_completions'.
+    """
+    pdef = get_provider(provider)
+    if pdef is not None:
+        return TRANSPORT_TO_API_MODE.get(pdef.transport, "chat_completions")
+
+    # URL-based heuristics for custom / unknown providers
+    if base_url:
+        url_lower = base_url.rstrip("/").lower()
+        if url_lower.endswith("/anthropic") or "api.anthropic.com" in url_lower:
+            return "anthropic_messages"
+        if "api.openai.com" in url_lower:
+            return "codex_responses"
+
+    return "chat_completions"
+
+
+# -- Provider from user config ------------------------------------------------
+
+def resolve_user_provider(name: str, user_config: Dict[str, Any]) -> Optional[ProviderDef]:
+    """Resolve a provider from the user's config.yaml ``providers:`` section.
+
+    Args:
+        name: Provider name as given by the user.
+        user_config: The ``providers:`` dict from config.yaml.
+
+    Returns:
+        ProviderDef if found, else None.
+    """
+    if not user_config or not isinstance(user_config, dict):
+        return None
+
+    entry = user_config.get(name)
+    if not isinstance(entry, dict):
+        return None
+
+    # Extract fields
+    display_name = entry.get("name", "") or name
+    api_url = entry.get("api", "") or entry.get("url", "") or entry.get("base_url", "") or ""
+    key_env = entry.get("key_env", "") or ""
+    transport = entry.get("transport", "openai_chat") or "openai_chat"
+
+    env_vars: List[str] = []
+    if key_env:
+        env_vars.append(key_env)
+
+    return ProviderDef(
+        id=name,
+        name=display_name,
+        transport=transport,
+        api_key_env_vars=tuple(env_vars),
+        base_url=api_url,
+        is_aggregator=False,
+        auth_type="api_key",
+        source="user-config",
+    )
+
+
+def resolve_provider_full(
+    name: str,
+    user_providers: Optional[Dict[str, Any]] = None,
+) -> Optional[ProviderDef]:
+    """Full resolution chain: built-in → models.dev → user config.
+
+    This is the main entry point for --provider flag resolution.
+
+    Args:
+        name: Provider name or alias.
+        user_providers: The ``providers:`` dict from config.yaml (optional).
+
+    Returns:
+        ProviderDef if found, else None.
+    """
+    canonical = normalize_provider(name)
+
+    # 1. Built-in (models.dev + overlays)
+    pdef = get_provider(canonical)
+    if pdef is not None:
+        return pdef
+
+    # 2. User-defined providers from config
+    if user_providers:
+        # Try canonical name
+        user_pdef = resolve_user_provider(canonical, user_providers)
+        if user_pdef is not None:
+            return user_pdef
+        # Try original name (in case alias didn't match)
+        user_pdef = resolve_user_provider(name.strip().lower(), user_providers)
+        if user_pdef is not None:
+            return user_pdef
+
+    # 3. Try models.dev directly (for providers not in our ALIASES)
+    try:
+        from agent.models_dev import get_provider_info as _mdev_provider
+        mdev_info = _mdev_provider(canonical)
+        if mdev_info is not None:
+            return ProviderDef(
+                id=canonical,
+                name=mdev_info.name,
+                transport="openai_chat",
+                api_key_env_vars=mdev_info.env,
+                base_url=mdev_info.api,
+                source="models.dev",
+            )
+    except Exception:
+        pass
+
+    return None

run_agent.py

@@ -1268,6 +1268,129 @@ class AIAgent:
             # Iterative summary from previous session must not bleed into new one (#2635)
             self.context_compressor._previous_summary = None
     
+    def switch_model(self, new_model, new_provider, api_key='', base_url='', api_mode=''):
+        """Switch the model/provider in-place for a live agent.
+
+        Called by the /model command handlers (CLI and gateway) after
+        ``model_switch.switch_model()`` has resolved credentials and
+        validated the model.  This method performs the actual runtime
+        swap: rebuilding clients, updating caching flags, and refreshing
+        the context compressor.
+
+        The implementation mirrors ``_try_activate_fallback()`` for the
+        client-swap logic but also updates ``_primary_runtime`` so the
+        change persists across turns (unlike fallback which is
+        turn-scoped).
+        """
+        import logging
+        from hermes_cli.providers import determine_api_mode
+
+        # ── Determine api_mode if not provided ──
+        if not api_mode:
+            api_mode = determine_api_mode(new_provider, base_url)
+
+        old_model = self.model
+        old_provider = self.provider
+
+        # ── Swap core runtime fields ──
+        self.model = new_model
+        self.provider = new_provider
+        self.base_url = base_url or self.base_url
+        self.api_mode = api_mode
+        if api_key:
+            self.api_key = api_key
+
+        # ── Build new client ──
+        if api_mode == "anthropic_messages":
+            from agent.anthropic_adapter import (
+                build_anthropic_client,
+                resolve_anthropic_token,
+                _is_oauth_token,
+            )
+            effective_key = api_key or self.api_key or resolve_anthropic_token() or ""
+            self.api_key = effective_key
+            self._anthropic_api_key = effective_key
+            self._anthropic_base_url = base_url or getattr(self, "_anthropic_base_url", None)
+            self._anthropic_client = build_anthropic_client(
+                effective_key, self._anthropic_base_url,
+            )
+            self._is_anthropic_oauth = _is_oauth_token(effective_key)
+            self.client = None
+            self._client_kwargs = {}
+        else:
+            effective_key = api_key or self.api_key
+            effective_base = base_url or self.base_url
+            self._client_kwargs = {
+                "api_key": effective_key,
+                "base_url": effective_base,
+            }
+            self.client = self._create_openai_client(
+                dict(self._client_kwargs),
+                reason="switch_model",
+                shared=True,
+            )
+
+        # ── Re-evaluate prompt caching ──
+        is_native_anthropic = api_mode == "anthropic_messages"
+        self._use_prompt_caching = (
+            ("openrouter" in (self.base_url or "").lower() and "claude" in new_model.lower())
+            or is_native_anthropic
+        )
+
+        # ── Update context compressor ──
+        if hasattr(self, "context_compressor") and self.context_compressor:
+            from agent.model_metadata import get_model_context_length
+            new_context_length = get_model_context_length(
+                self.model,
+                base_url=self.base_url,
+                api_key=self.api_key,
+                provider=self.provider,
+            )
+            self.context_compressor.model = self.model
+            self.context_compressor.base_url = self.base_url
+            self.context_compressor.api_key = self.api_key
+            self.context_compressor.provider = self.provider
+            self.context_compressor.context_length = new_context_length
+            self.context_compressor.threshold_tokens = int(
+                new_context_length * self.context_compressor.threshold_percent
+            )
+
+        # ── Invalidate cached system prompt so it rebuilds next turn ──
+        self._cached_system_prompt = None
+
+        # ── Update _primary_runtime so the change persists across turns ──
+        _cc = self.context_compressor if hasattr(self, "context_compressor") and self.context_compressor else None
+        self._primary_runtime = {
+            "model": self.model,
+            "provider": self.provider,
+            "base_url": self.base_url,
+            "api_mode": self.api_mode,
+            "api_key": getattr(self, "api_key", ""),
+            "client_kwargs": dict(self._client_kwargs),
+            "use_prompt_caching": self._use_prompt_caching,
+            "compressor_model": _cc.model if _cc else self.model,
+            "compressor_base_url": _cc.base_url if _cc else self.base_url,
+            "compressor_api_key": getattr(_cc, "api_key", "") if _cc else "",
+            "compressor_provider": _cc.provider if _cc else self.provider,
+            "compressor_context_length": _cc.context_length if _cc else 0,
+            "compressor_threshold_tokens": _cc.threshold_tokens if _cc else 0,
+        }
+        if api_mode == "anthropic_messages":
+            self._primary_runtime.update({
+                "anthropic_api_key": self._anthropic_api_key,
+                "anthropic_base_url": self._anthropic_base_url,
+                "is_anthropic_oauth": self._is_anthropic_oauth,
+            })
+
+        # ── Reset fallback state ──
+        self._fallback_activated = False
+        self._fallback_index = 0
+
+        logging.info(
+            "Model switched in-place: %s (%s) -> %s (%s)",
+            old_model, old_provider, new_model, new_provider,
+        )
+
     def _safe_print(self, *args, **kwargs):
         """Print that silently handles broken pipes / closed stdout.