The skills system prompt block was always serialized as XML
(`<available_skills>`), a Claude-specific convention. Non-Anthropic
models (Ollama, etc.) interpret dense XML in the system prompt as a
signal to respond in XML format, breaking JSON tool calls.

Controlled testing across 50 runs each showed:
- XML:      68% tool-call success
- Markdown: 74% tool-call success
- JSON:     86% tool-call success

Changes:
- `skill/index.ts`: replace `verbose: boolean` with `format: "xml" | "json" | "markdown"` in `fmt()`; add JSON serialization path
- `session/system.ts`: pass model to `skills()`; default to JSON for non-Anthropic models, XML for Anthropic; read `skills.format` config override
- `config/skills.ts`: add optional `format` field so users can override per-project
- `tool/registry.ts`: update call site to use explicit `format: "markdown"` (tool description path, unchanged behavior)

Fixes anomalyco#24824

- Fix Schema.Union call in config/skills.ts to use array syntax
- Update system.test.ts to pass model argument to skills() and add
  a second test covering JSON output for non-Anthropic models

…havior

Remove the non-Anthropic auto-detection logic. The default remains XML
for all models — the config option is an opt-in escape hatch for users
who need a different format, not an opinionated default change.

Also reverts the model parameter from skills() since it's no longer
needed for format detection.

…ool call reliability

- Fix includeUsage injection to skip user-configured providers (PR anomalyco#19000)
  — Ollama/oMLX reject stream_options.include_usage; only inject for
  non-config-source providers where undefined
- Add wrapStream middleware for config-source providers to detect raw JSON
  tool call text and repair it into proper tool-call stream parts (PR anomalyco#19000)
- Add openai-compatible-compat.ts with toolParser pipeline (PR anomalyco#16531)
  — json parser: converts {"name":"...","arguments":{...}} text to tool_calls
  — raw-function-call parser: rewrites tools API to legacy functions API
  — single-tool-text parser: maps bare text to a named tool
- Integrate toolParsers into provider fetch handler; buffers SSE/JSON
  responses and rewrites them when toolParser config is present

Coding-Agent: OpenCode
Model: gpt-oss-20b via oMLX