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

Annotations already cover the safety profile (readOnlyHint=true), but the description goes further by disclosing the polling cadence (re-reads employer sites, marks closed within ~36 hours), the three-valued result space, and the 'last confirmed' timestamp. That is genuinely useful behavioral context beyond the structured fields, though it does not discuss failure/auth behavior when a site is unreachable beyond the 'unknown' state.

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?

Compact single sentence with the core answer front-loaded and supporting detail (cadence, result values, confirmation time) in a parenthetical. No wasted preamble, though the nested clauses make it slightly dense to parse in one pass.

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 carries the burden of describing the return value and does so fully: open/closed/unknown plus the last confirmation time and the freshness window. Combined with the annotations, an agent has enough to call and interpret this tool.

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 coverage is 50%: url is documented in the schema, job_id is not. The description only indirectly signals that a careers-site link is the primary input ('given its careers-site link') and says nothing about job_id or about the unusual fact that neither parameter is required (one of the two must presumably be supplied). Baseline 3 is appropriate given the partial coverage.

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 precise verb+resource ('Whether a job posting is still on the employer's own careers site') and names the three-state answer. It is clearly distinguishable from siblings like compare_job_posting and hiring_market, which do comparative/market work rather than liveness checks.

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 clause 'Works for any employer's posting, given its careers-site link' gives usable scope and a precondition, implying when the tool applies. But there is no explicit when-not guidance or routing against the sibling tools, leaving the agent to infer that this is the right call for liveness questions.

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