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MCP server

Introduction

The MCP server is https://nthbouncer.com/mcp. How to add that URL in Cursor, Claude, or another client is on Agents. This page is what the assistant can do after you approve the grant.

MCP never admits traffic on the proxy, and pool keys never call MCP tools. They are separate credentials with separate jobs.

Session keys

When an assistant needs to call an HTTP origin, it starts a session. That returns the pool's base URL, a key, and an expiry. It sends requests to that base URL with the key in X-Nthpool-Key, keeping the path and query it would have used against the origin.

Session keys default to read-only. list_pools and start_pool_session return allowed / allowed_text so the assistant sees the grant list (GET *, then any extra method and its paths) even when the pool description does not mention it. Anything else is refused with 403 before the request leaves our edge. If the work genuinely writes, check Allow writes for that pool (or all pools) on the consent screen. The assistant cannot grant itself more than you approved.

Keys default to a one-hour life. Call end_pool_session when the work finishes so the key stops working immediately.

On a managed pool, the assistant never receives your origin's credential. It goes to the pool URL with the session key, and the upstream credential is added at our edge.

On a pass-through pool there is nothing to hide. The caller supplies the upstream credential itself, so assistants working with pass-through pools still need it.

Tools

Tool What it does
list_pools Pools this connector may use, their purpose, budget names, and concurrency
start_pool_session Pool base URL, a short-lived key, and an expiry
end_pool_session Revokes that key early
get_pool_usage Requests, admitted share, and queue wait

Database pools add these when the grant covers one:

Tool What it does
pool_schema Tables and columns
pool_count_rows How many rows a table (or filter) has
pool_query Run a read-only query. Slow queries can return a handle instead of rows.
get_query_result Page a query that returned a handle

Assistants only see the tools their grant allows.

There is also a use_pool prompt, which writes the few lines to add to a repo's AGENTS.md or CLAUDE.md so later sessions skip discovery. Ask for it once per project and commit the result.

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