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

Annotations already declare destructive and idempotent behavior, but the description goes beyond by specifying the exact chain revoked, the idempotent second-call response (`{ revoked: false, reason: 'already_revoked' }`), and the not_oauth_token error case. This adds meaningful behavioral detail not present in the 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?

Two tight sentences: the first gives the core action and object, the second covers idempotency and the key exception. No filler, and the most important differentiator (which token chain is revoked) is 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 zero-parameter destructive auth action, the description covers purpose, scope, idempotent behavior, error case, and the alternative mechanism. There is no output schema, so mentioning the idempotent response and failure mode is especially helpful. Nothing critical is missing.

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 tool has zero parameters, so the schema fully covers parameter surface (100% coverage). Per the baseline for 0-param tools, a 4 is appropriate since there is no parameter ambiguity to resolve, and the description correctly focuses on behavior instead.

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 uses a specific verb and resource: 'Disconnect this OAuth connection by revoking the access+refresh chain that issued the token making this call.' It clearly distinguishes this from any generic auth operation and from auth_whoami, and it even names the alternative path for br_ik_* keys.

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?

It explicitly states when this tool applies (OAuth tokens) and when it does not ('Refuses with not_oauth_token when called under an br_ik_* instance key'), plus what to do instead ('rotate those from the dashboard instead'). No inference is required.

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