Verify authentication

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

Annotations already declare readOnly, idempotent, non-destructive and openWorld, so the safety profile is covered. The description adds real context beyond that: it discloses the mechanism (token is checked via a custom-model API read) and explicit negative guarantees (no entitlement proof, no token disclosure), which is meaningful behavioral disclosure.

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?

Three short sentences, none wasted: purpose, mechanism, then scope limits. Front-loaded and readable, though the mechanism sentence is slightly terse for the concept it conveys.

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 and no parameters, but the rich annotations plus the description's stated mechanism and negative guarantees give enough to call it correctly. It stops short of saying how failure surfaces or what a success result looks like, which is the only meaningful gap.

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?

With zero parameters the baseline is 4, but the description references 'a supplied access token' while the schema exposes no properties at all, creating a mismatch an agent could act on. The mechanism note is useful, but the phantom-input reference costs a point.

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 ('Verify OAuth credentials or a supplied access token') and immediately differentiates from the generate_* siblings by noting it operates 'without generating media'. An agent can identify this as the auth-check tool without opening any 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?

Usage context is only implied - one would infer this is a pre-flight check before calling generation tools, but there is no explicit 'use this when...' or reference to sibling alternatives. The limitations ('does not prove generation entitlement') hint at scope but do not guide selection.

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