Operational guide

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

Annotations already declare readOnly, idempotent, non-destructive and non-open-world behavior, so the safety profile is covered. The description adds genuinely new context: it is local, returns a {"guide": markdown} payload, and 'may run during a search' — a hint about possible invocation timing, though that phrase is vague and never explained.

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?

Very short and front-loaded: identity/equivalence first, then the audience condition, then the return shape. The trailing fragment 'Local; may run during a search' is terse to the point of ambiguity, which costs a point.

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 zero-parameter, read-only tool with an output schema and full annotation coverage, the description supplies everything essential: what it returns, the resource equivalent, and the client condition. The only incompleteness is the unexplained 'may run during a search' behavior.

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 document; the schema is empty and fully covered. Baseline of 4 applies since no parameter ambiguity exists.

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 identifies exactly what is returned: the long operational guide as markdown, equivalent to the viajante://guide resource. No sibling tool serves a comparable purpose, so there is nothing to disambiguate against, but the retrieval verb is only implicit and the guide's subject matter is not stated.

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?

It gives an explicit selection condition: 'For clients that do not read MCP resources,' which implies the resource is the preferred path when available. That is clear when-to-use guidance, though it does not say what to do for clients that do read resources or note any other constraints.

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