odysseus/specs/model-providers/ollama.md

Ollama Provider Shape

Last updated: dev@e71f8ce | 2026-08-25

Scope

Canonical provider ID ollama; native Ollama chat/generate plus OpenAI compatibility; reader src/model_capability_readers/ollama.py; discovery and runtime code in routes/model_routes.py and src/llm_core.py.

Catalog And Detail Shapes

Use two native steps:

1. GET /api/tags returns models[] identity (name/model, digest, details.family|families, format, parameter size, quantization). Tags do not claim capabilities.
2. POST /api/show for a selected model returns explicit capabilities[], details, and model_info. Map completion/chat, embedding, vision, tools, and thinking/reasoning tokens. Map context from exact context_length or native <architecture>.context_length fields.

The reader does not parse model names or architecture names. It does parse a two-column serialized parameters value and can take num_ctx from it before falling back to exact or suffix *.context_length keys in structured mappings. The parameters text is used only for that keyed limit lookup, not capability inference.

Request And Response Shape

Native chat uses /api/chat, messages, optional OpenAI-shaped tool definitions, format, options, and model-dependent think. Responses use message.content, message.thinking, and message.tool_calls. Generate uses top-level response and thinking. OpenAI compatibility is a separate dialect and can change control names independently.

Manual Ollama endpoints registered against the OpenAI-compatible /v1 surface default to text/prompted tools unless the operator explicitly enables supports_tools; model naming alone does not opt that dialect into native function schemas.

Thinking control is model-specific: most documented reasoning families accept a native bool, while GPT-OSS accepts low/medium/high and cannot be fully disabled. A reported Ollama 0.20.6 Qwen3.5 OpenAI-compat path requires reasoning_effort: none rather than think: false (#5503); keep it versioned and low-confidence until corroborated.

Fallback And Safety

Current reader detection identifies port 11434 as Ollama, in addition to an explicit endpoint kind or an exact/label-bounded ollama.com hostname. This is a normalization hint, not endpoint trust or capability evidence. Names that contain vision, embed, or qwen are not capability evidence (#3743, #4487).

Current Gaps

• List discovery needs an orchestrated /api/show detail step per model.
• Runtime OpenAI-compat thinking suppression still contains name heuristics.