From 943465235ee8e33f903e34b964ec6bfe5b7cffbf Mon Sep 17 00:00:00 2001
From: briandevans <252620095+briandevans@users.noreply.github.com>
Date: Sun, 26 Apr 2026 09:09:03 -0700
Subject: [PATCH] fix(compressor): guard against bare-string items in
 multimodal content list
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raw_content from message["content"] can be a list that contains bare
strings, not only dicts.  The previous `p.get("text", "")` call raised
AttributeError on string items, crashing context compression for any
session that had a message with mixed content.

Guard with isinstance checks: dict → .get("text"), str → len(p),
fallback → len(str(p)).  Adds a regression test covering the bare-string
case that would have AttributeError'd on the pre-fix code.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
---
 agent/context_compressor.py            |  9 ++++++++-
 tests/agent/test_context_compressor.py | 15 +++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/agent/context_compressor.py b/agent/context_compressor.py
index 306c07b216..9f90a96163 100644
--- a/agent/context_compressor.py
+++ b/agent/context_compressor.py
@@ -1084,7 +1084,14 @@ The user has requested that this compaction PRIORITISE preserving all informatio
             msg = messages[i]
             raw_content = msg.get("content") or ""
             content_len = (
-                sum(len(p.get("text", "")) for p in raw_content)
+                sum(
+                    len(p.get("text", ""))
+                    if isinstance(p, dict)
+                    else len(p)
+                    if isinstance(p, str)
+                    else len(str(p))
+                    for p in raw_content
+                )
                 if isinstance(raw_content, list)
                 else len(raw_content)
             )
diff --git a/tests/agent/test_context_compressor.py b/tests/agent/test_context_compressor.py
index ed0848b3c8..883745d6c8 100644
--- a/tests/agent/test_context_compressor.py
+++ b/tests/agent/test_context_compressor.py
@@ -922,6 +922,21 @@ class TestTokenBudgetTailProtection:
         assert isinstance(cut, int)
         assert 0 <= cut <= len(messages)
 
+    def test_mixed_list_with_bare_strings_does_not_crash(self, budget_compressor):
+        """Content list may contain bare strings (not dicts) — must not raise AttributeError."""
+        c = budget_compressor
+        c.tail_token_budget = 500
+        # Bare string item alongside a dict item — normalisation elsewhere allows this.
+        mixed_content = ["Hello, world!", {"type": "text", "text": "extra text"}]
+        messages = [
+            {"role": "user", "content": mixed_content},
+            {"role": "assistant", "content": "ok"},
+        ]
+        head_end = 0
+        cut = c._find_tail_cut_by_tokens(messages, head_end)
+        assert isinstance(cut, int)
+        assert 0 <= cut <= len(messages)
+
 
 class TestUpdateModelBudgets:
     """Regression: update_model() must recalculate token budgets."""