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

The description goes well beyond the idempotentHint annotation: it explains that only the first cancellation is billed, later 'no' answers are free, keep-going answers cost nothing, unknown jobs answer keep-going, and failures return continue:null for retry. It also discloses the x402 billing mechanism and the Authorization/agent_key requirement, so the cost and side-effect profile is fully transparent.

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?

The description contains several useful caveats, but it is wordy and somewhat duplicative: the 'only billed on the first no and never again' idea appears twice. The first sentence is also awkwardly phrased, and the text could be tightened while keeping auth, billing, and failure-mode facts.

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 small two-parameter tool with no output schema, the description covers the full behavioral contract: how to interpret the answer, what to do on null, billing implications, authentication, and the equivalent HTTP route. An agent has enough information to invoke and react to the result correctly.

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?

The input schema already covers both parameters well (100% coverage), including job_id aliases and agent_key preferred usage. The description adds the header-vs-agent_key authentication preference but does not materially expand parameter semantics beyond the schema.

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 and title clearly identify this as a per-item continuation check for a job, returning 'keep going', 'no/stop', or a null failure state. It names the job resource and the between-items usage context, though it does not explicitly contrast with siblings like work_status or checkpoint_get.

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?

It gives a clear usage context: a worker calls it between items, and it instructs retrying when the state cannot be determined rather than guessing. It does not name explicit alternatives or exclusions, but the intended situation is clear enough.

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