Claude Code / AI Coding Tools
Claude Code MCP STDIO subprocess reaped mid-conversation without shutdown signal
Users running Claude Code with MCP STDIO-based tools experience server processes getting OS-reaped during conversations, then respawned without graceful shutdown, causing hung connections and tool failures. Includes evidence for Claude Code troubleshooting demand.
- Category
- AI Coding Tools
- Error signature
MCP STDIO subprocess reaped + respawned mid-conversation, no shutdown signal to the server- Quick fix
- Compare the failing environment with a known working setup, then change one configuration value at a time.
- Updated
What this error means
MCP STDIO subprocess reaped + respawned mid-conversation, no shutdown signal to the server is a Claude Code failure pattern reported for developers trying to users running claude code with mcp stdio-based tools experience server processes getting os-reaped during conversations, then respawned without graceful shutdown, causing hung connections and tool failures.. Based on the imported evidence, treat this as a tool-specific troubleshooting page rather than a generic API error.
Why this happens
Source: anthropics/claude-code#61146 (opened May 21, 2026, today — very recent). Labeled area:mcp and bug. MCP servers use STDIO transport; when parent process signals cause SIGTERM/SIGKILL, child servers restart without prior termination handshake. Affects developers relying on custom MCP tools (GitHub, databases, etc.) within Claude Code sessions. Category: AI Coding Tools — MCP auth/tool integration.
Common causes
- Source: anthropics/claude-code#61146 (opened May 21, 2026, today — very recent). Labeled area:mcp and bug. MCP servers use STDIO transport; when parent process signals cause SIGTERM/SIGKILL, child servers restart without prior termination handshake. Affects developers relying on custom MCP tools (GitHub, databases, etc.) within Claude Code sessions. Category: AI Coding Tools — MCP auth/tool integration.
Quick fixes
- Confirm the exact error signature matches
MCP STDIO subprocess reaped + respawned mid-conversation, no shutdown signal to the server. - Check the Claude Code account, local tool state, and provider configuration involved in the failing workflow.
- Compare the failing environment with a known working setup, then change one configuration value at a time.
Platform/tool-specific checks
- Verify the command, editor, extension, or API client that produced the error.
- Compare local settings with CI, deployment, or editor-level settings when the error appears in only one environment.
- Avoid deleting credentials, local model data, or project settings until the failing scope is clear.
Step-by-step troubleshooting
- Capture the exact error message and the command, editor action, or request that triggered it.
- Check whether the failure is account/auth, quota/rate, model/provider, local runtime, or deployment configuration.
- Review the source evidence below and compare it with your environment.
- Apply one change at a time and rerun the smallest failing action.
- Keep the working fix documented for the team or deployment environment.
How to prevent it
- Keep provider/tool configuration documented.
- Record non-secret diagnostics such as tool version, provider name, model name, and command path.
- Add a lightweight check before CI or production workflows depend on the tool.
Sources checked
Evidence note: Source: anthropics/claude-code#61146 (opened May 21, 2026, today — very recent). Labeled area:mcp and bug. MCP servers use STDIO transport; when parent process signals cause SIGTERM/SIGKILL, child servers restart without prior termination handshake. Affects developers relying on custom MCP tools (GitHub, databases, etc.) within Claude Code sessions. Category: AI Coding Tools — MCP auth/tool integration.
Related errors
- AI Coding Tools
FAQ
What should I check first?
Start with the exact MCP STDIO subprocess reaped + respawned mid-conversation, no shutdown signal to the server text and the smallest action that reproduces it.
Can I ignore this error?
No. Treat it as a failed Claude Code workflow until the root cause is understood.
Is this guaranteed to have one fix?
No. The imported evidence supports the troubleshooting path above, but tool behavior can vary by account, plan, version, provider, and local configuration.
How do I know the fix worked?
Rerun the same command, editor action, or request. The fix is working when that action completes without MCP STDIO subprocess reaped + respawned mid-conversation, no shutdown signal to the server.