get_api_key_usage

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

With no annotations supplied, the description carries the full disclosure burden. It states that the operation returns counts only, contains no recipient identifiers, is scoped to the authenticated account, and that API-key callers can only read their own key. It also discloses the auth requirement and how to unlock access. This meaningfully exceeds a bare 'Get usage' statement.

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?

The description is compact and well-structured: the first sentence covers purpose and output scope, then the ACCESS paragraph provides actionable setup instructions. The metric list is dense but relevant, and there is no filler or repetition. It is slightly long but each clause earns its place.

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?

There is no output schema, so the description compensates by enumerating the return categories: verification counts by type/channel/status, verification-request/confirmation/authorization totals, and attribution context. It also covers access setup and account scoping. It doesn't specify the exact response structure, but for a usage-read tool the description is largely 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 description coverage is 100%: both `id` and `environment` have descriptive text in the schema. The description reinforces `id` ('for a given key id') but adds no extra meaning for `environment` or the default value. Baseline 3 is appropriate since the schema fully documents the parameters.

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: 'Get per-API-key usage for a given key id'. It enumerates exactly what is returned (verification counts by type/channel/status, totals, attribution context), making the tool's purpose unmistakable. It doesn't explicitly contrast with sibling tools like get_usage or get_platform_summary, but the 'per-API-key' and 'given key id' phrasing inherently distinguishes it.

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 gives clear access prerequisites and scoping rules: 'Scoped to the authenticated account; an API-key caller may read only its own key', plus setup instructions using PROOF_API_KEY or start_login. However, it does not say when to prefer this tool over siblings like get_usage or get_platform_summary, and no explicit alternatives/exclusions are provided.

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