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

Annotations already declare readOnlyHint=false, openWorldHint=true, non-idempotent, non-destructive. The description adds valuable context beyond annotations: credit cost (1-4 per page), the 409 refusal condition (another run queued/running), URL host constraint, and the follow-up workflow (get_job with kind 'run', then get_changes). It does not explain what happens if some URLs fail or the exact shape of the returned run, but the coverage is strong.

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?

Front-loads the core action, then scenario, alternatives, cost, constraint, failure mode, and return/workflow. Every sentence earns its place with no redundancy.

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 mutation tool with 2 well-documented params and annotations covering safety profile, the description fills remaining gaps: cost, failure condition, host constraint, and the follow-up workflow using sibling tools. An agent has everything needed to call this correctly and interpret the result.

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%, so the schema already defines both parameters well. The description reinforces the URL constraint ('must be on the project's site') and the credit-per-page cost, adding value beyond the schema's bare '1 to 500 full URLs on the project's site'.

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+scope: 'Fetch specific pages of a project again now, as a small run of their own...compares just those pages with the last full run.' Explicitly distinguishes from siblings start_run ('re-crawls everything') and extract_url ('reads a page outside any project').

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 the intended scenario ('check a few pages you expect changed without crawling the whole site') and names two alternatives (start_run and extract_url) with the conditions that select them. Nothing is left to inference.

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