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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description adds real value beyond that by disclosing the three things returned (open status, first-seen date, repost flag), which is the main behavioral unknown for a lookup tool. It does not say what happens for an unsupported or malformed URL, which is the remaining gap.

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?

A single sentence, front-loaded with the input and the primary output, with the source examples placed where they disambiguate. No filler or restatement of the tool name.

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 one-parameter read-only lookup with no output schema, the description does the important work of enumerating the return fields and the accepted source domains. Only the failure behavior (unsupported URL, unreachable page) and the sibling distinction are 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?

With one parameter at 100% schema coverage, the baseline is 3; the description earns above baseline by constraining the URL to employer career sites and named ATS platforms, which is meaning the schema's bare 'The job posting's URL' does not convey. It still doesn't specify whether redirects, expired pages, or non-ATS URLs are tolerated.

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 ('report whether it is still open') on a specific resource ('the URL of a job posting') and even names the target ecosystem (Greenhouse, Lever, Ashby, Workday). It is immediately distinguishable in intent, though it never mentions the siblings get_job or search_jobs to sharpen the boundary.

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 is implied rather than stated: an agent can infer this is the tool for verifying liveness of a known URL, but there is no explicit 'use this when X, use search_jobs when Y' routing. No prerequisites, error conditions, or exclusions are given.

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