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

Annotations already declare readOnly/openWorld, but the description adds genuinely non-obvious behavior: required USAJOBS_API_KEY and USAJOBS_EMAIL env vars and the resulting 503 when absent. It also discloses the billing model ($0.002 USDC per successful call via x402, failed calls not charged), which an agent cannot infer from anything else.

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?

Core purpose is front-loaded in the first clause, followed by key/auth requirements and pricing in a logical order. The sibling-comparison sentence is slightly long-winded for two tangential alternatives, but no sentence is filler.

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 an output schema present, the description needn't explain returns, yet it summarizes fields anyway; it also covers auth failure mode and cost. Only rate limits and pagination behavior are unaddressed, which is minor for a two-parameter read-only search.

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%, so keyword and limit are already documented in the schema. The description adds no syntax, defaults, or format detail beyond that, so baseline 3 applies.

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+resource ('US federal job openings from the official USAJOBS Search API') and enumerates the returned fields, so the agent knows exactly what it retrieves. It also explicitly contrasts itself with jobs_jooble and jobs_bayt, making the scope difference legible without opening a schema.

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?

Names two alternatives with the conditions that select them ('when you need job search on Jooble's aggregator', 'when you need Bayt.com ... Middle East and North Africa'), which is real routing guidance. It stops short of exclusions against closer siblings like jobs_governmentjobs or the US boards (indeed, dice), so the guidance is clear but not fully exhaustive.

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