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

Annotations already declare readOnly/openWorld/idempotent/non-destructive behavior, so the safety profile is covered. The description adds real behavioral value not present in the schema: it discloses the return content ('blocking errors, recommended fixes and a summary per posting') and a key negative ('never the page itself'), which matters because there is no output schema. It omits fetch/auth/privacy caveats for the `url` mode, keeping it below a 5.

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?

Two sentences, no filler, and the core purpose plus validation target are front-loaded before the input-mode detail. Every clause carries information.

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 correctly compensates by summarizing the return shape (errors, fixes, summary) and its exclusion of page content. Parameter semantics are fully covered, but behavior when both inputs are provided, or on fetch failure of `url`, is not addressed.

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 0%, so the description must carry parameter meaning, and it does: `html` accepts page HTML or JSON-LD, `url` accepts a public page address. That clarifies both parameters and the either/or usage implied by zero required fields, though it doesn't address whether both may be supplied simultaneously or how conflicts are resolved.

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 ('Check') and resource ('a job post's schema.org JobPosting markup') and names the external authority it validates against ('Google's job search rules'). This is clearly distinguishable from siblings like get_job, search_jobs, or check_pay_transparency.

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?

Explains the two input modes ('Pass the page HTML or JSON-LD as `html`, or a public page address as `url`'), which is genuine usage guidance for choosing how to call it. It does not, however, state when to prefer this over siblings such as check_pay_transparency or get_job, so it stops short of explicit when/when-not routing.

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