v1.15.13 Desktop GUI hides MCPs that don't implement prompts/list

[klebersonend]

Description

After updating to v1.15.13, the OpenCode Desktop GUI no longer displays any MCP servers, even though they are correctly configured in opencode.json and work fine via CLI/TUI.

Downgrading to v1.15.12 restores the MCP list in the GUI.

Root Cause
The logs show:

ERROR service=mcp clientName=postgres-contaazul error=MCP error -32601: Method not found failed to get prompts
Starting in v1.15.13, OpenCode calls prompts/list on every connected MCP server. Most MCP servers (postgres, filesystem, github, playwright, etc.) do not implement the prompts capability and return -32601 Method not found. This error is now treated as a fatal UI error, causing all MCPs to be hidden from the Desktop GUI, even though their tools work perfectly via the agent.

Expected Behavior
MCPs that fail prompts/list should still be displayed as available in the GUI. The prompts capability is optional per the MCP spec — servers should not be penalized for not implementing it.

Environment
OpenCode Desktop v1.15.13 (Windows x64)
All MCPs configured via opencode.json
MCPs confirmed working via CLI (v1.4.7) and via agent tool calls
Logs
ERROR service=mcp clientName=postgres-contaazul error=MCP error -32601: Method not found failed to get prompts
ERROR service=mcp clientName=github-referencias error=MCP error -32601: Method not found failed to get prompts
ERROR service=mcp clientName=filesystem-save-queries error=MCP error -32601: Method not found failed to get prompts

Plugins

No response

OpenCode version

OpenCode Desktop v1.15.13 (Windows x64)

Steps to reproduce

No response

Screenshot and/or share link

No response

Operating System

No response

Terminal

No response

[github-actions]

This issue might be a duplicate of existing issues. Please check:

• MCP hidden from UI panel when server doesn't implement prompts/list (-32601) #20174: MCP hidden from UI panel when server doesn't implement prompts/list (-32601) — same root cause
• MCP compatibility: don't error when prompts/list is unsupported (-32601) #26048: MCP compatibility: don't error when prompts/list is unsupported (-32601) — same fix requested
• MCP servers functional but invisible in Desktop v1.15.13 UI #30098: MCP servers functional but invisible in Desktop v1.15.13 UI (closed) — nearly identical report for the same version

Please review these issues and comment there if you have additional information to add, rather than tracking this separately.