Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full behavioral burden and meets it thoroughly. It discloses side effects (tokenRevision increment invalidates older session JWTs), validation checks (signature, tokenType=SESSION, Firebase UID match), expiry extension, email backfill, and auth forwarding as Bearer.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is dense but front-loaded with the core behavior, then covers path form, encoding, auth, and configuration. It is longer than a minimal description, but the extra sentences earn their place; only the final generic config sentence feels slightly tangential.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a mutating auth operation with no output schema, the description is remarkably complete: it gives the path, HTTP method, auth requirement, URL-encoding, return values, side effects, and validity duration. An agent has enough to invoke it correctly without guessing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The description adds important semantics beyond the schema: sessionToken must be URL-encoded in the path, may be expired, and is parsed without expiry enforcement; auth.firebaseToken is forwarded as a Bearer token. It could have also elaborated on connection.appId/workspaceName usage, but the schema descriptions cover those basics.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific action: verify the Firebase ID token, consume an internal SESSION JWT from the sessionToken path segment, increment tokenRevision, and return a new sessionToken. It is clearly distinct from sibling tools like revoke or get_or_create because it focuses on replacing an existing token without enforcing JWT expiry.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description makes the intended use apparent: renew an expired or expiring session JWT, since JWT expiry is explicitly not enforced and server-side expiry is extended by one hour. It does not explicitly name sibling alternatives or state when not to use it, but the context is clear enough for an agent to select it.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.