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

Annotations already declare readOnly, idempotent, closed-world and non-destructive, so the safety profile is covered. The description adds real context beyond them: the call requires no API key and is not rate-limited/quota-limited, which matters for an agent deciding whether it can call this during onboarding. It stops short of describing the response structure, but the annotations carry the rest.

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?

Two short fragments, front-loaded with the most decision-relevant fact (no key, no quota). It is appropriately sized for a zero-param discovery tool, though the telegraphic style is slightly clipped even for its length.

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 no-parameter, read-only directory tool with no output schema, the description tells the agent what comes back (routes, OpenAPI doc location, docs location) and that access is unrestricted. Little else is needed; only the exact return shape is left to discovery.

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 for the description to disambiguate; baseline 4 applies. No parameter discussion is expected or missing.

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 names the resource precisely — 'Every REST route' plus the location of the OpenAPI document and docs — which is clearly distinct from sibling tools like get_setup_fields or fetch. The verb is elided (it reads as a noun phrase), but the resource is unambiguous.

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?

'No key and no quota' implies this is a bootstrap/discovery call usable before authentication, which is implicit usage guidance. However, it never states when to prefer this over siblings such as get_setup_fields or get_coverage, nor what an agent should do with the returned routes.

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