MCP tools not sent to local OpenAI-compatible models (empty tools array)

Description

When using a local model via an OpenAI-compatible provider (Ollama proxy), OpenCode sends tools: [] (empty array) instead of the actual MCP tool definitions. The model responds with plain text because it never receives the tool definitions.

The same configuration works correctly with the Anthropic/Claude provider.

Environment

• OpenCode: 1.18.5
• Provider tested: @ai-sdk/openai-compatible v3.0.7 and @ai-sdk/openai v4.0.11
• Local model: deepseek-v4-flash-stock (also qwen3.5:9b-stock)
• Proxy: Ollama proxy (OpenAI-compatible endpoint)
• MCP servers: filesystem, fetch
• OS: Linux (CachyOS)

Steps to reproduce

1. Configure local model with "tools": true in opencode.json
2. Enable MCP servers (filesystem, fetch)
3. Start OpenCode with local model
4. Ask the model to use a tool
5. Model responds with text, no tool call

Expected

Model receives MCP tool definitions and calls the appropriate tool.

Actual

OpenCode sends tools: [] (empty array). Logs show:

WARN "MCP connection closed" server=filesystem
WARN "schema rejection" kind=Payload reason="Expected object, got undefined"

Direct test (works)

Same request sent directly to the proxy WITH tool definitions → model responds with correct tool_calls. The model and proxy are not the problem.

Note

Affects both @ai-sdk/openai-compatible and @ai-sdk/openai. Does NOT occur with Anthropic/Claude provider.