using ACP in Zed throws error: ACP mcpServers are not supported yet; configure MCP servers in ~/.jcode/mcp.json or a project-local .jcode/mcp.json/.mcp.json

[focccus]

Summary

When Jcode runs as an ACP agent server (e.g. via Zed's agent_servers), the host editor passes mcpServers in the ACP agent/session.new request. Jcode treats this as a fatal error and refuses to start the session, making Jcode unusable as an external agent in any host that has MCP/context servers configured.

Environment

• Jcode v0.75.0 (5ae2385), Windows x86_64
• Host: Zed (latest stable) via ACP (jcode acp)
• Zed has context_servers configured (svelte-docs, astro-docs, linear, figma, anytype, github, bun-docs)

Steps to reproduce

1. Configure context_servers in Zed's settings.json (any enabled MCP server will trigger it).
2. Add Jcode as a custom agent server:

   "agent_servers": {
     "jcode": {
       "type": "custom",
       "command": "jcode",
       "args": ["acp"]
     }
   }

3. Open Zed's Agent Panel and select the Jcode agent.
4. Attempt to start a session.

Expected behavior

Jcode should ignore the mcpServers field in the ACP session.new request (or use it to connect to those servers). MCP servers should be loaded in addition to ~/.jcode/mcp.json or .jcode/mcp.json as documented. The session should start normally.

Actual behavior

Jcode emits a fatal error and the session fails to start:

ACP mcpServers are not supported yet; configure MCP servers in ~/.jcode/mcp.json or a project-local .jcode/mcp.json/.mcp.json

The error is non-recoverable. Jcode cannot be used as an ACP agent in any host that forwards context servers.

Suggested fix

1. Short term: If mcpServers is present in the request, log a debug-level warning and continue session creation normally, loading MCP servers from the config files as usual.
2. Long term: Accept mcpServers from the ACP request and merge them with the file-based config, so host-provided servers work alongside locally configured ones.

Workaround

Disable all context_servers in Zed's settings.json (set each to "enabled": false). This prevents Zed from forwarding them in the ACP request, but also removes them from Zed's own agent panel.

Related

• ACP hosts get no slash commands: Zed blocks /-prefixed input with "Available commands for jcode: none" #851
• support for remote MCP servers #483
• Expose MCP server prompts as slash commands #698

[1jehuang]

Fixed in PR #889. Valid ACP mcpServers arrays are now tolerated and ignored during session creation/loading, while malformed non-array values remain rejected. The focused regression test passes.

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— Jcode agent (automated triage), on behalf of @1jehuang

[1jehuang]

Additional verification: I built the PR branch and exercised the real jcode acp stdio interface with initialize followed by session/new containing a non-empty mcpServers array. Session creation succeeded with a real sessionId and command update; the process exited cleanly without the former unsupported-field error.

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— Jcode agent (automated triage), on behalf of @1jehuang