fix(tools): stop ToolSearch description claiming nonexistent deferral

Root-cause follow-up to the ToolSearch gate: pythinker emits no defer_loading
and ToolSearch only searches already-visible, already-callable tools (it
unlocks nothing). The old description told the model that "deferred/hidden
tool loading" might leave capabilities off the prompt — a false claim that
primed weaker models to loop searching for tools they already had. Rewrite it
to state plainly that it reveals nothing new and to call tools directly.

Author: elkaix

CHANGELOG.md

@@ -21,7 +21,9 @@ GitHub Releases page; `0.8.0` is the new starting line.
   `type="anthropic"` compat proxies (z.ai/GLM, Kimi, MiniMax, opencode) and all
   non-Anthropic providers no longer see it, fixing a loop where weaker tool-callers
   (e.g. GLM-5.2) repeatedly "searched" for tools instead of calling them. Override
-  with `ENABLE_TOOL_SEARCH=true|false`.
+  with `ENABLE_TOOL_SEARCH=true|false`. The tool's description no longer claims that
+  hidden/deferred tools exist (pythinker loads no tools lazily), removing the prompt
+  that primed the loop in the first place.
 - **Output-token-limit nudge text aligned with reference.** The system-reminder injected when a response is cut off by the output token limit now matches the reference byte-exactly: "Output token limit hit. Resume directly — no apology, no recap of what you were doing. Pick up mid-thought if that is where the cut happened. Break remaining work into smaller pieces."
 - **`SetTodoList` accepts Cursor-style todo payloads.** Todo items sent with `content` instead of `title` (the shape models learn from Cursor/Claude `TodoWrite`) now validate and persist correctly instead of failing with missing-`title` errors.
 - **ToolSearch scrollback suppression.** Consecutive `ToolSearch` probes during deferred tool discovery are now collapsed: only the last probe in each run is shown in the transcript, mirroring the blackbox `isAbsorbedSilently` contract. Intermediate discovery calls no longer produce repeated "Tools(…)" lines.

src/pythinker_code/tools/tool_search/tool_search.md

@@ -1,7 +1,9 @@
 Search the currently visible tool list by name and description.
 
-Use this when you are unsure which tool is available for a task or when deferred/hidden tool
-loading means the initial prompt may not list every useful capability. The search only returns
-tools visible under the current runtime and permission profile.
+Use this only when you are unsure which existing tool fits a task. It returns tools that are
+already available to you under the current runtime and permission profile — it does NOT load,
+unlock, or reveal any hidden tools. Everything it can return is already callable directly, so
+prefer calling the tool you need over searching for it; searching does not make any new tool
+available.
 
 Provide concise keywords such as `worktree`, `background task`, `read file`, or `web search`.

tests/tools/test_tool_search.py

@@ -77,3 +77,13 @@ async def test_tool_search_excludes_hidden_tools() -> None:
     assert not result.is_error
     assert "ReadProjectFiles" not in result.output
     assert result.output == "No visible tools matched `read files`."
+
+
+def test_description_does_not_claim_nonexistent_deferral() -> None:
+    """Guard the trigger of the GLM-5.2 loop: pythinker has no defer_loading, so
+    the ToolSearch description must not imply hidden/deferred tools exist or that
+    searching unlocks anything. See test_tool_search_gating + the toolset gate."""
+    desc = ToolSearch(PythinkerToolset()).description.lower()
+    assert "deferred" not in desc
+    assert "hidden" in desc and "does not" in desc  # explicitly says it unlocks nothing
+    assert "already callable" in desc