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

Adds real context beyond annotations: free/not metered, rate-limited, the full status object shape, and that a done result matches web_crawl's shape. One residual tension is left unaddressed: readOnlyHint=true while action=cancel stops a running job, so the description should clarify that cancel only terminates the job and does not alter fetched data or crawl results.

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?

Purpose, when-to-use, when-not-to-use, and return shape are ordered by decision value, with no filler sentences. The inline return-shape list is dense but earns its space given there is no output schema.

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 two-parameter control tool with no output schema, the description covers the lifecycle, terminal states, progress fields, error field, cost, and rate limiting — everything needed to call it and interpret the response 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?

Schema coverage is 100% and the enum already documents 'Poll status (default) or cancel the job', so the description largely restates it via 'poll with action=status' and 'action=cancel to stop a running job'. It adds the polling-until-terminal-state habit, but no format or edge-case detail about job_id beyond what the schema says.

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?

Opens with a specific verb pair and resource ('Check or cancel an asynchronous crawl job') and ties it back to the creating tool, web_crawl_async. An agent can distinguish it from web_crawl_async, web_fetch, and web_monitor_* without opening any 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?

Explicit 'When to use' names the polling pattern and termination states, and explicit 'Do not use' names the two alternatives (web_crawl_async to start, web_fetch for quick single-page reads) with the condition that selects each. The action=status vs action=cancel split is spelled out.

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