Refresh an access token

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

Annotations already convey the safety profile (readOnlyHint=false, destructiveHint=false, non-idempotent, open-world). The description adds the key operational trigger (401 failures), which is the behavior an agent most needs. It does not mention token lifetime or whether the old refresh token is rotated, which would be a useful extra.

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?

Two tight sentences: the mechanism first, the trigger second. No filler, everything front-loaded.

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 simple token-exchange tool with full schema descriptions and no output schema, this covers what an agent needs to call it correctly. The remaining gap is return-value shape, which is not strictly required since no output schema exists.

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 all four parameters are already documented, including fallback behavior for app_id/app_secret and the scope-narrowing semantics. The description adds nothing beyond the schema, so the baseline 3 applies.

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?

Specific verb ('Trade') and resource ('refresh token for a fresh access token'), and it clearly distinguishes itself from the OAuth siblings (build_oauth_url, exchange_oauth_code) by naming the refresh-token exchange.

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 states the triggering condition: 'Use this when calls start failing with 401.' That gives the agent a concrete signal for when to invoke this rather than retry or re-authorize.

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