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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so the safety profile is fully covered by structured data. The description adds only the mild behavioral note that the index is 'self-describing'; it does not say what the index contains, whether it enumerates endpoints or schemas, or how large the response is.

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 short sentence with the key fact front-loaded; nothing is wasted. It is arguably slightly under-specified rather than verbose, but structurally it is clean.

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?

There is no output schema, so the description carries the burden of indicating what comes back. 'Self-describing index' gestures at the return shape but does not say whether it yields endpoint names, schemas, or versions — which is the main thing an agent needs to know before calling a discovery endpoint.

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 per the rubric this is a baseline 4. There is nothing for the description to disambiguate, and it correctly implies a no-argument call.

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?

The description gives a clear verb and resource — 'Discovers the whole PageAudit API' — and the parenthetical '(self-describing index)' clarifies what is returned. It does not need to distinguish itself much from siblings like audit_url or billing, since those are obviously different operations, but it also never states that distinction.

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 only implied: the phrase 'Discovers the whole... API' suggests a top-level discovery entry point, but there is no explicit when-to-use statement, no mention of it being a first-call orientation tool, and no guidance relative to siblings such as list_tools or get_tool, which could plausibly serve a similar discovery role.

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