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

Annotations already declare readOnly, idempotent, and non-destructive behavior. The description adds valuable context beyond that: counts include the current call, an Agent Pass starts at the first call other than this one, and it names specific blockers. This gives the agent meaningful behavioral detail.

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 dense but every clause adds relevant information, and the key purpose is front-loaded. It is somewhat run-on and hard to parse due to dashes and nested clauses, but there is no fluff or repetition beyond the title echo.

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?

Given the output schema exists, the description does not need to explain return values. It covers what the tool reports, when to call it, and access prerequisites. The main limitation is the awkward prose, which may make some details easy to miss, but nothing critical appears absent.

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 and schema coverage is 100%, so there is nothing to clarify. The description still notes access requirements (key or sign-in), which is useful but not parameter-specific. Baseline for zero-parameter tools is appropriately strong.

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 clearly states what the tool reports: the API key's tier, remaining requests and calls, whether fit_resume and apply tools would work, and blocker details. It differentiates itself from siblings like application_status and check_apply_support by focusing on the key itself rather than job or application state.

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 explicitly says to call it first in a keyed session and after quota/rate refusals. It does not discuss when not to use it or name alternatives, but the use case is clearly specified.

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