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droid 0.190.0: ACP daemon passes unsupported --mcp-servers to child process -> "Droid process exited unexpectedly (exit code 1)" #9
Description
Activity
Still reproduces on droid 0.233.0 (npm
droid@0.233.0, Linux x64), via T3 Code's ACP registry integration (droid exec --output-format acp-daemon).Minimal repro over stdio JSON-RPC:
→ {"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":1,"clientCapabilities":{}}} → {"jsonrpc":"2.0","id":2,"method":"session/new","params":{"cwd":"/tmp/x","mcpServers":[{"name":"t","command":"/bin/cat","args":[],"env":[]}]}} ← {"jsonrpc":"2.0","id":2,"error":{"code":-32603,"message":"Internal error","data":{"details":"Droid process exited unexpectedly (exit code 1)"}}}The daemon still spawns
droid exec --output-format acp --session-id <id> --mcp-servers <base64>, and the child still exits witherror: unknown option '--mcp-servers'. With"mcpServers": []the session opens and prompts work, BYOK custom models included.Related: the child's stderr never reaches the ACP client, so all a client can show is "exited unexpectedly (exit code 1)". Forwarding the child's stderr in
data.detailswould have made this self-diagnosing.Hey @shuuul, It has been fixed in the latest 0.234.0 version; please try it out and let us know!
Reacted by shuuul- added a commit that references this issue
on Oct 8, 2026
Droid version: 0.190.0 (both
$HOME/.local/bin/droidand npmdroid@0.190.0)OS: macOS (arm64)
Zed version: 1.14.2
What happened
Using Factory Droid as an ACP agent from Zed (external_agents registry entry runs
droid exec --output-format acp-daemon) always fails with:Evidence (from
$HOME/.factory/logs/droid-log-single.log)The ACP daemon spawns a child process and passes a
--mcp-serversargument:The child exits immediately with:
(exit code 1), which the wrapper reports as
ProcessExitError: Droid process exited unexpectedly (exit code 1).--mcp-serversis not defined fordroid execin 0.190.0 (confirmed viadroid exec --helpon both installs).The base64 payload is a JSON list of the client's MCP servers, so the failure occurs whenever the ACP client has any MCP/context servers enabled (reproduced with stdio-style servers such as exa-search and with http-style servers such as deepwiki). With no servers configured, session creation succeeds and the daemon works.
Steps to reproduce
--mcp-serversflag; the child exits 1 and the client shows the error above.Expected behavior
droid execaccepts--mcp-servers, or the ACP daemon stops passing flags that the exec command does not support.Impact
Factory Droid in Zed is unusable whenever any MCP/context servers are enabled. 0.190.0 is the latest version on npm as of 2026-08-09, so there is no known fixed version to upgrade to.