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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the description needn't restate the safety profile. It adds real value by disclosing what the response contains — the enumerated resource set — which is the key behavioral fact for a no-output-schema tool. It does not mention the response format or that entries may be absent for some sites.

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?

A single sentence that front-loads the verb and scope, then packs the enumeration into a compact list. Every clause earns its place and nothing is repeated from the title.

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 zero parameters, full annotation coverage, and no output schema, the only burden is describing what is returned — which the enumeration does well. It stops short of saying how entries are formatted or what a missing resource looks like, a minor gap for a discovery tool.

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 tool takes zero parameters, so there is nothing to disambiguate; baseline 4 applies. The description correctly signals that no arguments are needed.

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 ('List') plus a specific resource ('this site's machine-readable resources for AI agents'), then enumerates the six artifacts returned (llms.txt, API catalog, OpenAPI spec, skills index, auth policy, MCP server). An agent knows exactly what comes back without opening the schema, and the name is unmistakable against the unrelated eviction/closing-fee siblings.

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?

Usage is implied by the tool's nature (a zero-argument discovery endpoint) but never stated: no 'call this first to discover available capabilities', no exclusions or prerequisites. Nothing misleads, but the agent must infer the call context itself.

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