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

Goes well beyond the destructiveHint annotation by spelling out exactly what is affected: the target agent and all agents that joined through its codes lose access to the owner's balance and utilities, and the owner's open invite codes stop working, while no data is deleted and no money moves. It also discloses the authentication model (OAuth app sign-in or passport-key-signed request) and the failure mode for token auth (signature_required), which is exactly the kind of context annotations cannot carry.

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 action and scope in the first clause, then layers effects, limits, and auth in a logical order with no filler. It is longer than typical but every sentence carries operational information; only the invite-code aside is borderline expendable.

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?

With no output schema, the description still tells the agent what changes (access revoked, invite codes invalidated), what does not change (no deletion, no money movement), what auth is required, and what error to expect with token auth. For a destructive, security-sensitive mutation this is complete.

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 baseline is 3; however the description adds real meaning beyond the schema by explaining the security behavior of passport_token (a leaked token yields signature_required and can never perform this action) and by tying the passport value to list_passports' id_prefix. This is useful semantics rather than restatement.

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 (unlink), a specific resource (an agent/passport) and a precise scope restriction (only agents that joined AFTER you), plus a concrete example use case. It also names list_passports as the way to discover which passports are removable, so the tool is distinguishable from siblings without opening a schema.

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?

Gives clear when-to-use context (agent joined after you, e.g. a stranger via leaked invite code) and explicit when-not conditions (cannot unlink you or an agent that joined before you). It does not explicitly contrast with nearby siblings like revoke_passport or leave_owner, so routing between those is left to inference.

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