qwen3:14b (and deepseek-r1, other reasoning models) wrap their output
in <think>…</think> chains-of-thought before emitting real output.
With format=json the constrained sampler terminated immediately at
`{}` because the thinking block wasn't valid JSON; without format the
model thinks normally and appends the actual JSON at the end.
OllamaClient now omits the format flag and extracts the outermost
balanced `{…}` block from the response (brace depth counter, string-
literal aware). Works for reasoning models, ```json``` code-fenced
outputs, and plain JSON alike.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
format=json loose mode gives valid JSON but no shape — models default
to emitting {} when the system prompt doesn't list fields. Prepend a
schema-guidance system message with the full Pydantic schema (after
the existing null-branch sanitiser) so the model sees exactly what
shape to produce. Pydantic still validates on parse.
Unit tests updated to check the schema message is prepended without
disturbing the caller's own messages.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Ollama 0.11.8 segfaults on any Pydantic-shaped structured-output schema
with $ref, anyOf, or pattern — confirmed on the deploy host with the
simplest MVP case (BankStatementHeader alone). The earlier null-stripping
sanitiser wasn't enough.
Switch to format="json", which is "emit valid JSON" mode. We're already
describing the exact JSON shape in the system prompt (via GenAIStep +
the use case's citation instruction appendix) and validating the
response body through Pydantic on parse — which raises IX_002_001 on
schema mismatch, exactly as before.
Stronger guarantees can come back later via a newer Ollama, an API
fix, or a different GenAIClient impl. None of that is needed for the
MVP to work end to end.
Unit tests: the sanitiser left in place (harmless, still tested). The
"happy path" test now asserts format == "json".
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Ollama 0.11.8's llama.cpp structured-output implementation segfaults on
Pydantic v2's standard Optional pattern:
{"anyOf": [{"type": "string"}, {"type": "null"}]}
Confirmed on the deploy host: /api/chat request with the MVP's
ProvenanceWrappedResponse schema crashed Ollama with SIGSEGV; the client
saw httpx RemoteProtocolError → IX_002_000.
New _sanitise_schema_for_ollama walks the schema recursively and drops
"type: null" branches from every anyOf. Single-branch unions are
inlined so sibling keys (default, title) survive. This only narrows
what the LLM is *told* it may emit; Pydantic still validates the real
response body against the original schema and accepts None for
Optional fields if they were absent or explicitly null.
Existing unit tests updated: the "happy path" test no longer pins the
format to `_Schema.model_json_schema()` verbatim — instead it asserts
the sanitisation effect on a known-Optional field.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Real GenAIClient for the production pipeline. Sends `format=<pydantic JSON
schema>`, `stream=false`, and mapped options (`temperature`; drops
`reasoning_effort`). Content-parts lists joined to a single string since
MVP models don't speak native content-parts. Error mapping per spec:
connection/timeout/5xx → IX_002_000, schema violations → IX_002_001.
`selfcheck()` probes /api/tags with a fixed 5 s timeout for /healthz.
Tests: 10 hermetic pytest-httpx unit tests; 2 live tests gated on
IX_TEST_OLLAMA=1 (never run in CI).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
