Stdio handshake timeout with npx local MCPs (env expansion suspect) #12229

Summary

Local MCP servers using npx hang/time out in OpenCode. opencode mcp list shows 60s timeouts for local stdio MCPs, while running the same npx commands manually works. Suspect stdio handshake or env expansion issue ("${TOKEN}" passed literally).

Environment

• OS: Linux
• OpenCode: 1.1.51
• Transport: local stdio (npx)

Repro

1. Configure local MCP servers with command: [\"npx\", \"-y\", \"@modelcontextprotocol/server-filesystem\", \"/home/user\"]
2. Run opencode mcp list
3. Observe timeouts for local servers

Observed

filesystem: Operation timed out after 60000ms
memory: Operation timed out after 60000ms
sequential-thinking: Operation timed out after 60000ms
everything: Operation timed out after 60000ms
github: Operation timed out after 10000ms
brave-search: Operation timed out after 10000ms

Remote MCPs (context7) and local python server (neogsd_triad) connect fine.

Expected

Local MCPs should connect and register tools, as they do when run directly with npx.

Notes

• npx -y @modelcontextprotocol/server-filesystem /home/user runs fine manually.
• Previously, bunx produced Connection closed; npx now times out.
• Config includes env var placeholders like ${GITHUB_TOKEN}, possible expansion issue.

Config snippet (sanitized)

"filesystem": {"type":"local","command":["npx","-y","@modelcontextprotocol/server-filesystem","/home/user"],"enabled":true,"timeout":60000}