Permit MCP Gateway vs Restate

Permit MCP Gateway

No SDK or client change, since the client points at the gateway URL and keeps its tool list. Approvals are Enterprise only, through a demo, with no published price.

Restate

An awakeable pauses a handler at no compute cost and resumes it from one HTTP request, with a durable timeout, on a free plan of 100,000 actions a month. Restate sends nothing to the approver, so the Slack message, email or inbox is the builder's code, and the published terms and privacy statement predate the paid plans.

Permit MCP Gateway

1. Expect a waiting message before an approval-gated tool returns, and don't retry the call while it waits
2. Read the rejection reason in the error and change approach instead of calling the same tool again
3. Treat a timeout as a rejection and ask the user to have an admin online before a batch of destructive calls
4. Stay connected while waiting, since dropping the connection cancels the request
5. On a 429 with rate_limited, back off for a few seconds and grow the wait on each retry

Restate

1. Create the awakeable, send its ID inside ctx.run, then await the promise, so a retry doesn't send a second approval request
2. Resolve with POST /restate/awakeables/<id>/resolve and a JSON body, or /reject with a text reason, which throws a terminal error in the handler
3. On Restate Cloud send Authorization: Bearer key_... to https://<env_id>.env.<region>.restate.cloud:8080. On a self-hosted server put an authenticating proxy in front of port 8080
4. Wrap the wait in orTimeout and decide what a timeout means. Without it the handler waits with no limit
5. Retry ingress errors only on 408, 425, 429 or 5xx, and only when x-restate-error-source isn't invocation