mcp-tool-cache-stale-when-server-rebuilt-mid-session
When an MCP server is rebuilt (docker-compose up —build) mid-session, Claude Code’s tool cache retains the old tool names and signatures from session start. New tools added in the rebuilt image are not visible until the session is reconnected. Verification of new tool registration must use direct MCP protocol calls (curl to health endpoint + SSE tool listing) rather than Claude Code’s tool search, which reads from the stale cache.