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

Beyond the annotations, it discloses important side effects: the refreshToken is rotated on every call and must be stored. It also reveals session-binding requirements and the 7-day grant lifetime, which are not visible in the schema or annotations.

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?

Every sentence earns its place: the primary action, lifetime constraints, token rotation requirement, and session prerequisite are all included without filler. The most important action is front-loaded, and the detail is dense but coherent.

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 tool with no output schema, the description covers the key behavioral and lifecycle context needed for correct use: token rotation, persistence, expiry, and re-pairing. It does not explicitly describe the response shape, but the instruction to store the new token implies the response contains it, which is likely sufficient for an agent.

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 coverage is 100%, so the schema already documents all three parameters. The description reinforces that refreshToken comes from poll_pairing and that it gets rotated, but it does not add materially new parameter-level meaning beyond what the schema already provides.

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 opens with a specific verb and resource: 'Renew a short-lived access token (~1h) using the refreshToken from poll_pairing.' It clearly differentiates itself from related tools like get_pairing_code and poll_pairing, and the title aligns with the action.

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 explicitly states when to use the tool and when not to: use it to renew tokens within the 7-day grant window, and re-pair via get_pairing_code after expiration. It also provides a concrete prerequisite—same MCP-Session-Id as pairing—and a fallback instruction if fingerprint mismatch occurs.

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