Discover destinations

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

Annotations already declare readOnly, idempotent, non-destructive, so the safety profile is covered. The description adds two things annotations can't: that the catalog is anonymous (no auth needed) and that its results are non-authoritative for eligibility — a meaningful caveat that changes how an agent should treat the output.

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 sentences, no filler, with the eligibility caveat placed where it will be read. The opening sentence is a bare noun phrase rather than an action statement, which slightly weakens front-loading but costs little in 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 parameterless, non-destructive read with an empty schema and no output schema, the agent needs to know what it gets (an anonymous catalog) and how far to trust it (not eligibility). Both are stated; the remaining gaps, such as result shape, are minor for a tool this simple.

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 clarify; baseline 4 applies. The description does not waste space restating an empty schema.

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 calls itself an "Anonymous catalog with source references and requirements," which implies a listing operation but never states a verb+resource openly (e.g., "lists directories"). Combined with the title "Discover destinations" and the name list_directories, an agent can infer the purpose, but nothing in the text distinguishes it from siblings like list_servers or list_connections.

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?

The second sentence sets a clear boundary: discovery does not establish purchase eligibility, and a full authenticated preflight (matched to the run_preflight/get_preflight siblings) is the alternative. It tells the agent when this tool is insufficient, though it never positively states the browsing/exploration scenario where it should be used.

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