Idempotency

A Claude Code MCP write waits in a retry queue beyond its approval expiry, keeps the same operation ID, and is blocked by an execution-time authority check

Claude Code queued an approved MCP write. It ran after permission expired

A stable operation ID can stop duplicate MCP writes while still allowing an action after its approval expires. Recheck authority where the effect occurs.

Two parallel Claude Code writes request operation IDs from one atomic identity ledger, which issues unique IDs and blocks collisions before MCP dispatch

Claude Code gave two parallel writes the same operation ID

Two parallel Claude Code tool calls can share an operation ID and corrupt retry evidence. Allocate identity centrally, bind it to intent, and reject collisions before dispatch.

A timed-out Claude Code MCP request leaves a paid remote job running while a guarded retry looks up the operation and attaches to the existing job

Claude Code timed out, retried, and paid twice

A timed-out MCP call may still be running and charging your account. Give paid tool operations a stable ID, a spend ceiling, and a retry receipt before Claude Code tries again.

A timed-out Claude Code MCP write enters an unknown state, checks an operation journal, and either verifies the existing effect or retries with the same idempotency key

Treat a timed-out MCP write as an unknown outcome

A timed-out MCP write may have failed, succeeded, or finished after the client gave up. Use an operation journal and effect lookup before Claude Code retries it.

Claude Code sends a write through an MCP tool, receives a timeout, and verifies the external system before continuing, retrying, or stopping

A Claude Code tool timeout does not mean the action failed

A timed-out MCP tool call may have completed after the connection closed. Verify the external result before Claude Code retries a write.