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

Annotations cover the safety profile (readOnly, non-destructive, open world), and the description adds value beyond them: no credits charged ('Free'), the scoring output shape, the disputed 8-point bonus rule and its optionality, and the fix-prompt artifact. These are operational facts an agent cannot derive from the annotations or schema.

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-loaded with purpose, output, and cost before the workflow guidance, and every sentence carries distinct information (scoring rules, bonus caveat, outreach workflow, self-audit). The outreach-workflow sentence is long and could be tightened, but nothing is truly redundant.

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 no output schema and only one parameter, the description carries the return-value burden and does so explicitly (0-100 score plus per-check pass/fail plus fix prompt). Combined with the cost note and the bonus caveat, an agent has everything needed to call this 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 description coverage is 100% and the single url parameter already has an example in the schema, so the description is not required to explain parameters. It adds no syntax, format, or constraint detail beyond what the schema provides, so the 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?

Specific verb ('scans') + resource ('a public site') + the exact standard being evaluated (AI-agent readiness, llms.txt v2 shape). It also names the concrete artifact produced (0-100 score with per-check pass/fail), which separates it cleanly from siblings like discover_email or get_trends.

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?

Explicitly describes a common workflow (search the web, scan each site, then call discover_email on the lowest-scoring ones) and names the exact selection condition (lowest score = outreach hook). It also gives a second use case (self-audit of the user's own sites), so both when-to-use paths are covered.

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