Discover Tools & Resources

A client should never assume what a server can do. Once connected, it discovers the available capabilities by asking the server to list them.

Call session.list_tools() and the server returns every tool it exposes, ready for your code to inspect.

The result carries a tools list. Each entry has a name and a human-readable description so you know what it does.

Every tool also exposes an inputSchema, a JSON Schema describing the arguments it accepts. This is how you learn what to send.

Servers can offer read-only data too. Call session.list_resources() to fetch the set of resources you may read.

Each resource is addressed by a uri, like a file path or a custom scheme. You use that uri later to fetch its contents.

The third primitive is prompts. session.list_prompts() reveals reusable instruction templates the server publishes.

You only get what the server advertised at the handshake. If it declared no resources, listing them returns an empty set.

Discovery means a client adapts at runtime. Plug in a new server and its tools simply appear, with no client code changes needed.

Discovered tool names, descriptions, and schemas are exactly what a model needs to decide which tool fits a request later on.

Tool lists can change, so a careful client may re-list after an update notification rather than trusting a stale snapshot.

Which session call returns the server tool list with their schemas?

You learned to discover a server at runtime: list its tools, resources, and prompts, then read each name, description, and schema before acting.