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

Beyond the readOnly/openWorld annotations, the description discloses the data source and its limitations (no salary or location fields exist in the feed, so they are absent from results), and a full cost/payment model: $0.002 USDC per successful call via x402 on Base/Solana/Arc, with failed calls not charged. That is exactly the kind of context annotations cannot convey.

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, front-loaded with what the tool returns and immediately followed by the two facts an agent cannot get elsewhere: absent fields and per-call pricing. No filler or repetition of the title.

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?

An output schema exists, so return structure need not be restated; the description nonetheless names the key fields and explicitly rules out salary/location. Combined with the pricing and failure-charge policy, an agent has everything needed to decide and invoke.

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?

There is a single parameter, limit, and the schema already documents its range (1–50) and default (10) at 100% coverage. The description adds nothing about limit behavior or ordering beyond 'newest,' so the baseline 3 for high schema coverage 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?

Names a specific verb and resource — newest 4-day-week and flexible job postings — and identifies the exact source (4dayweek.io's public RSS feed), plus the fields returned (role title, company/author, link, publish time). That niche framing cleanly separates it from the many general job-board siblings like jobs_indeed or jobs_flexjobs.

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 implies usage context by scoping to 4-day-week/flexible roles, so an agent can infer when this source is relevant. However, it never explicitly states when to prefer it over a sibling (e.g. FlexJobs, We Work Remotely) or any exclusions, leaving the routing decision to inference.

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