fix: follow-up for salvaged PR #8952

- Rename provider_contracts.py -> volcengine_byteplus.py for explicitness
- Consolidate duplicate host-to-provider mappings: provider_for_base_url()
  now uses the canonical _URL_TO_PROVIDER from model_metadata.py instead of
  maintaining a separate 20-entry dict
- Add volcengine/byteplus to runtime_provider.py model-dependent base URL
  resolution (kimi-style special case) so manually-edited configs resolve
  the coding-plan base URL correctly
- Remove volcengine/byteplus from _API_KEY_PROVIDER_AUX_MODELS — the
  main-model-first design in _resolve_auto() handles these providers
  already; entries were dead code in the normal flow
- Add VOLCENGINE_API_KEY and BYTEPLUS_API_KEY to OPTIONAL_ENV_VARS in
  config.py so they appear in hermes setup
- Update docs: environment-variables.md, fallback-providers.md,
  configuration.md

hermes_cli/volcengine_byteplus.py

@@ -0,0 +1,134 @@
+"""Source-of-truth contracts for built-in providers without models.dev catalogs."""
+
+from __future__ import annotations
+
+from typing import Dict, List, Tuple
+
+VOLCENGINE_PROVIDER = "volcengine"
+BYTEPLUS_PROVIDER = "byteplus"
+
+VOLCENGINE_STANDARD_BASE_URL = "https://ark.cn-beijing.volces.com/api/v3"
+VOLCENGINE_CODING_PLAN_BASE_URL = "https://ark.cn-beijing.volces.com/api/coding/v3"
+BYTEPLUS_STANDARD_BASE_URL = "https://ark.ap-southeast.bytepluses.com/api/v3"
+BYTEPLUS_CODING_PLAN_BASE_URL = "https://ark.ap-southeast.bytepluses.com/api/coding/v3"
+
+VOLCENGINE_STANDARD_MODELS: Tuple[str, ...] = (
+    "doubao-seed-2-0-pro-260215",
+    "doubao-seed-2-0-lite-260215",
+    "doubao-seed-2-0-mini-260215",
+    "doubao-seed-2-0-code-preview-260215",
+    "kimi-k2-5-260127",
+    "glm-4-7-251222",
+    "deepseek-v3-2-251201",
+)
+
+VOLCENGINE_CODING_PLAN_MODELS: Tuple[str, ...] = (
+    "doubao-seed-2.0-code",
+    "doubao-seed-2.0-pro",
+    "doubao-seed-2.0-lite",
+    "doubao-seed-code",
+    "minimax-m2.5",
+    "glm-4.7",
+    "deepseek-v3.2",
+    "kimi-k2.5",
+)
+
+BYTEPLUS_STANDARD_MODELS: Tuple[str, ...] = (
+    "seed-2-0-pro-260328",
+    "seed-2-0-lite-260228",
+    "seed-2-0-mini-260215",
+    "kimi-k2-5-260127",
+    "glm-4-7-251222",
+)
+
+BYTEPLUS_CODING_PLAN_MODELS: Tuple[str, ...] = (
+    "dola-seed-2.0-pro",
+    "dola-seed-2.0-lite",
+    "bytedance-seed-code",
+    "glm-4.7",
+    "kimi-k2.5",
+    "gpt-oss-120b",
+)
+
+VOLCENGINE_STANDARD_MODEL_REFS: Tuple[str, ...] = tuple(
+    f"{VOLCENGINE_PROVIDER}/{model_id}" for model_id in VOLCENGINE_STANDARD_MODELS
+)
+VOLCENGINE_CODING_PLAN_MODEL_REFS: Tuple[str, ...] = tuple(
+    f"{VOLCENGINE_PROVIDER}-coding-plan/{model_id}" for model_id in VOLCENGINE_CODING_PLAN_MODELS
+)
+BYTEPLUS_STANDARD_MODEL_REFS: Tuple[str, ...] = tuple(
+    f"{BYTEPLUS_PROVIDER}/{model_id}" for model_id in BYTEPLUS_STANDARD_MODELS
+)
+BYTEPLUS_CODING_PLAN_MODEL_REFS: Tuple[str, ...] = tuple(
+    f"{BYTEPLUS_PROVIDER}-coding-plan/{model_id}" for model_id in BYTEPLUS_CODING_PLAN_MODELS
+)
+
+PROVIDER_MODEL_CATALOGS: Dict[str, Tuple[str, ...]] = {
+    VOLCENGINE_PROVIDER: VOLCENGINE_STANDARD_MODEL_REFS + VOLCENGINE_CODING_PLAN_MODEL_REFS,
+    BYTEPLUS_PROVIDER: BYTEPLUS_STANDARD_MODEL_REFS + BYTEPLUS_CODING_PLAN_MODEL_REFS,
+}
+
+MODEL_CONTEXT_WINDOWS: Dict[str, int] = {
+    "doubao-seed-2-0-pro-260215": 256000,
+    "doubao-seed-2-0-lite-260215": 256000,
+    "doubao-seed-2-0-mini-260215": 256000,
+    "doubao-seed-2-0-code-preview-260215": 256000,
+    "kimi-k2-5-260127": 256000,
+    "glm-4-7-251222": 200000,
+    "deepseek-v3-2-251201": 128000,
+    "doubao-seed-2.0-code": 256000,
+    "doubao-seed-2.0-pro": 256000,
+    "doubao-seed-2.0-lite": 256000,
+    "doubao-seed-code": 256000,
+    "minimax-m2.5": 200000,
+    "glm-4.7": 200000,
+    "deepseek-v3.2": 128000,
+    "kimi-k2.5": 256000,
+    "seed-2-0-pro-260328": 256000,
+    "seed-2-0-lite-260228": 256000,
+    "seed-2-0-mini-260215": 256000,
+}
+
+
+def provider_models(provider_id: str) -> List[str]:
+    """Return the full user-facing model catalog for a provider."""
+    return list(PROVIDER_MODEL_CATALOGS.get(provider_id, ()))
+
+
+def _bare_model_name(model_name: str) -> str:
+    value = (model_name or "").strip()
+    if not value:
+        return ""
+    if "/" in value:
+        return value.split("/", 1)[1].strip()
+    return value
+
+
+def is_coding_plan_model(provider_id: str, model_name: str) -> bool:
+    """Return True when a model belongs to the coding-plan catalog."""
+    raw = (model_name or "").strip()
+    bare = _bare_model_name(raw)
+    if provider_id == VOLCENGINE_PROVIDER:
+        return raw in VOLCENGINE_CODING_PLAN_MODEL_REFS or bare in VOLCENGINE_CODING_PLAN_MODELS
+    if provider_id == BYTEPLUS_PROVIDER:
+        return raw in BYTEPLUS_CODING_PLAN_MODEL_REFS or bare in BYTEPLUS_CODING_PLAN_MODELS
+    return False
+
+
+def base_url_for_provider_model(provider_id: str, model_name: str) -> str:
+    """Resolve the source-of-truth base URL for a provider+model pair."""
+    if provider_id == VOLCENGINE_PROVIDER:
+        if is_coding_plan_model(provider_id, model_name):
+            return VOLCENGINE_CODING_PLAN_BASE_URL
+        return VOLCENGINE_STANDARD_BASE_URL
+    if provider_id == BYTEPLUS_PROVIDER:
+        if is_coding_plan_model(provider_id, model_name):
+            return BYTEPLUS_CODING_PLAN_BASE_URL
+        return BYTEPLUS_STANDARD_BASE_URL
+    return ""
+
+
+def model_context_window(model_name: str) -> int | None:
+    """Return a known context window for a model, if specified by the contract."""
+    bare = _bare_model_name(model_name)
+    return MODEL_CONTEXT_WINDOWS.get(bare)