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

Annotations already flag destructiveHint=true and idempotentHint=false, and the description adds the crucial concrete consequence: the old token is revoked immediately and the caller must save the new one when using raw HTTP. It also documents the X-Token-Expires-At header and the 30-day warning, well beyond what structured fields convey.

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?

Front-loads the core exchange-and-revoke behavior and keeps supporting detail (header, session behavior, alternatives) compact. Slight redundancy: 'REVOKES the old token immediately' and the closing 'The old token is revoked' say the same thing twice.

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?

No output schema exists, and the description compensates by naming the returned fields (token, token_expires_at), the default lifetime, and the session-level consumption behavior. An agent has everything needed to call and consume this correctly.

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?

Schema description coverage is 100% and the schema already states range 1-1825 and default 365 for expires_in_days; the description restates the same range and only marginally clarifies that the lifetime applies to the NEW token. Baseline 3 is appropriate since the schema carries the parameter meaning.

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?

States a specific verb and resource ('Exchange the CURRENT bearer token for a new one') and immediately disentangles itself from siblings like login and get_started by describing what it does versus what they do when the token is already expired.

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?

Explicitly gives the when (before expiry, within the 30-day warning window), the when-not (already expired tokens cannot be refreshed), and names the alternatives for that case ('log in again (login) or create a token in the cabinet').

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