Adds structured_output/output_schema/max_retries inputs to
OllamaChatCompletion, fixing three real reliability problems: models
prepending commentary, wrapping responses in code fences, and occasionally
returning blank output. When enabled, requests go through Ollama's
OpenAI-compatible tool-calling endpoint (a single forced tool call matching
output_schema) instead of native /api/chat, and each response is validated
against a dynamically-built pydantic model — invalid/blank responses retry
with fresh network calls, exhausting into a clear RuntimeError rather than
silently passing bad data downstream. One additional ComfyUI output socket
is exposed per schema property, mirroring FormatString's existing
dynamic-output pattern. Fully backward compatible: structured_output
defaults off and non-structured behavior is untouched.
Ollama's native /api/chat "format" field (JSON-Schema-constrained decoding)
was tried first but proved unreliable against a real local model during
implementation — see ADR-006 for the full investigation and why
tool-calling was chosen over both native format and pydantic-ai (the latter
would reintroduce httpx/openai-sdk, reversing ADR-004).
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
