fix(librarian): replace nullable tool params with sentinel defaults

Ollama's OpenAI-compatible API mishandles anyOf[X, null] parameter
schemas. update_wiki_page (content/title/tags/description) and
smart_create_wiki_page (path) now use empty-string/empty-list
sentinels translated to None inside the tool, following the
biographer pattern from 9d7ce39.

Adds a snapshot test that walks every registered librarian tool's
emitted JSON schema and fails on any anyOf[..., null].

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

CHANGELOG.md

@@ -15,6 +15,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
+- **Ollama-safe librarian tool schemas** - `update_wiki_page` and `smart_create_wiki_page` no longer use `X | None` parameters (Ollama's OpenAI-compatible API mishandles `anyOf[X, null]`); empty-string/empty-list sentinels are translated to `None` inside the tools, matching the biographer pattern. A snapshot test pins every librarian tool schema to contain no nullable `anyOf`
 - **Honest expert failures** - `run_librarian`/`run_librarian_stream` now raise a structured `AgentError` instead of returning error text as if it were research output, so delegation correctly reports `success=False` and the streaming error branch is reachable. Failures surface to the user as curated butler-toned sentences; exception detail (including internal URLs) stays in the logs only. Librarian tool errors no longer leak `str(e)` into synthesis
 
 - **HybridRAG response mapping** - The librarian client now parses the field names library-desk actually returns (`source_type`/`sources`, `rrf_score`, `context`, per-item `related_dossiers`, synonyms nested in the `keywords` dict); previously every result rendered as "unknown (score: 0.00)". Source icons now key off the per-item `sources` list. Requests no longer send zero limits (the service rejects them with 422); legs are disabled via `enable_*` flags. Pinned by a contract test against a recorded live response (`tests/agents/librarian/fixtures/`)

src/agents/librarian/tools.py

@@ -793,10 +793,10 @@ async def read_urls_batch(
 
 async def update_wiki_page(
     page_id: int,
-    content: str | None = None,
-    title: str | None = None,
-    tags: list[str] | None = None,
-    description: str | None = None,
+    content: str = "",
+    title: str = "",
+    tags: list[str] = [],  # noqa: B006 - sentinel, never mutated
+    description: str = "",
 ) -> str:
     """
     Update an existing wiki page.
@@ -810,12 +810,15 @@ async def update_wiki_page(
     - Updating tags to organize pages into dossiers
     - Fixing descriptions or titles
 
+    Note: empty values are sentinels for "leave unchanged" (Ollama's
+    OpenAI-compatible API mishandles anyOf[X, null] parameter schemas).
+
     Args:
         page_id: ID of the page to update (get from search_wiki results)
-        content: New markdown content (optional - only if changing content)
-        title: New title (optional - only if renaming)
-        tags: New tag list (optional - replaces existing tags)
-        description: New description (optional)
+        content: New markdown content (empty = leave unchanged)
+        title: New title (empty = leave unchanged)
+        tags: New tag list, replaces existing tags (empty = leave unchanged)
+        description: New description (empty = leave unchanged)
 
     Returns:
         Confirmation with updated page details
@@ -829,21 +832,21 @@ async def update_wiki_page(
         async with LibraryDeskClient() as client:
             page = await client.update_wiki_page(
                 page_id=page_id,
-                content=content,
-                title=title,
-                tags=tags,
-                description=description,
+                content=content if content else None,
+                title=title if title else None,
+                tags=tags if tags else None,
+                description=description if description else None,
             )
 
             # Build update summary
             updated_fields = []
-            if content is not None:
+            if content:
                 updated_fields.append("content")
-            if title is not None:
+            if title:
                 updated_fields.append("title")
-            if tags is not None:
+            if tags:
                 updated_fields.append("tags")
-            if description is not None:
+            if description:
                 updated_fields.append("description")
 
             output_parts = [
@@ -948,7 +951,7 @@ async def create_wiki_page(
 async def smart_create_wiki_page(
     topic: str,
     tags: list[str],
-    path: str | None = None,
+    path: str = "",
     include_web_research: bool = True,
     include_wiki_search: bool = True,
 ) -> str:
@@ -970,7 +973,7 @@ async def smart_create_wiki_page(
     Args:
         topic: The topic to research and create a page about
         tags: List of tags/dossiers for categorization
-        path: Optional custom path (auto-generated from topic if not provided)
+        path: Optional custom path (empty = auto-generated from topic)
         include_web_research: Whether to search the web (default: True)
         include_wiki_search: Whether to search existing wiki (default: True)
 
@@ -986,7 +989,7 @@ async def smart_create_wiki_page(
             response = await client.smart_create_wiki_page(
                 topic=topic,
                 tags=tags,
-                path=path,
+                path=path if path else None,
                 include_web_research=include_web_research,
                 include_wiki_search=include_wiki_search,
             )

tests/agents/librarian/test_tool_schemas.py

@@ -0,0 +1,49 @@
+"""
+Snapshot tests for the JSON schemas emitted for librarian tools.
+
+Ollama's OpenAI-compatible API mishandles anyOf[X, null] parameter
+schemas, so tool parameters must use empty-string/empty-list sentinels
+translated to None inside the tool (same pattern as the biographer
+tools, commit 9d7ce39). This test fails if a X | None parameter ever
+creeps back in.
+"""
+
+import pytest
+from pydantic_ai.tools import Tool
+
+from src.agents.librarian.tools import LIBRARIAN_TOOLS
+
+
+def _nullable_anyof_paths(schema: object, path: str = "") -> list[str]:
+    """Recursively collect JSON-schema paths that are anyOf[..., null]."""
+    offenders: list[str] = []
+    if isinstance(schema, dict):
+        any_of = schema.get("anyOf")
+        if isinstance(any_of, list) and any(
+            isinstance(sub, dict) and sub.get("type") == "null" for sub in any_of
+        ):
+            offenders.append(path or "<root>")
+        for key, value in schema.items():
+            offenders.extend(_nullable_anyof_paths(value, f"{path}/{key}"))
+    elif isinstance(schema, list):
+        for i, item in enumerate(schema):
+            offenders.extend(_nullable_anyof_paths(item, f"{path}[{i}]"))
+    return offenders
+
+
+@pytest.mark.unit
+class TestLibrarianToolSchemas:
+    """All registered librarian tools emit Ollama-safe parameter schemas."""
+
+    @pytest.mark.parametrize(
+        "tool_func", LIBRARIAN_TOOLS, ids=lambda f: f.__name__
+    )
+    def test_no_nullable_anyof_in_schema(self, tool_func):
+        schema = Tool(tool_func).function_schema.json_schema
+
+        offenders = _nullable_anyof_paths(schema)
+
+        assert offenders == [], (
+            f"{tool_func.__name__} emits anyOf[..., null] at {offenders}; "
+            "use empty-string/empty-list sentinels instead of X | None"
+        )