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

Annotations already cover read-only, open-world, idempotent, and non-destructive behavior, yet the description adds what the result contains (score, passed/failed checks, category results, top fixes, limitations, report link) and how reportUrl lets you revisit results. It does not mention any rate limits or access requirements for the scan, leaving a small gap.

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 the return value and the purpose, then the sibling routing, then the parameter usage. Three tight sentences with no filler.

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?

No output schema exists, and the description compensates by enumerating the returned fields, so an agent knows what to expect. A one-parameter read-only tool needs nothing more.

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% for the single url parameter, so baseline is 3. The description adds that the page must be public and clarifies the url-versus-reportUrl relationship, though reportUrl appears to be an output field rather than a parameter, which is slightly ambiguous.

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 and resource (scan a webpage for AI readiness) and enumerates what the scan yields. It also explicitly names the sibling tool it is not, so an agent can route without opening either 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?

Gives an explicit trigger ('when someone asks whether a webpage is accessible and usable by AI agents') and an explicit alternative ('for checking an MCP server's directory compliance, use check_mcp_server_directory_rules instead').

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