MCP client fails to initialize servers that don't implement optional prompts/list and resources/list methods #24985

Description

Description
When configuring MCP servers that only implement tools/list and tools/call (like sequential-thinking or mcp-grep), OpenCode fails to initialize them. The log shows: ERROR service=mcp clientName=... error=MCP error -32601: Method not found failed to get prompts.

Some MCP servers intentionally omit optional prompts/list and resources/list to keep their implementation minimal. While this is valid per the spec, OpenCode currently treats the -32601 response as a fatal error and discards the server.

Steps to Reproduce

1. Add the mcp-grep server to opencode.json:

   "mcp-grep": {
     "type": "local",
     "command": "mcp-grep",
     "enabled": true
   }

2. Start OpenCode.
3. Observe the error in the logs.

Expected behavior
OpenCode should gracefully handle -32601 on optional methods and continue, making the server's tools available.

Actual behavior
The server fails to initialize and its tools are unavailable.

Impact
All MCP servers that omit optional handlers are unusable, significantly limiting OpenCode's MCP ecosystem.

Environment:

• OpenCode version: [e.g., 1.14.29]
• OS: [Linux Mint 22.1]

Related Issue: The context-mode project added empty handlers to resolve OpenCode's behavior. Additionally, oh-my-openagent issue #1915 has the same root cause.

Plugins

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OpenCode version

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Steps to reproduce

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Screenshot and/or share link

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Operating System

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Terminal

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