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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), so the bar is lower, yet the description adds substantial context beyond them: reads never contact the server, results are cached five minutes, descriptions truncate at 4,000 chars and input schemas become null above 8,000, and `capacidades`/`suspeitas` are computed from current rules at read time. The only gap is that the 404 error behavior could be tied more explicitly to caller action.

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?

Front-loaded with what is returned, followed by error semantics, field normalization details and caching. Dense but each clause carries information; minor friction comes from the fragment opening and the untranslated `capacidades`/`suspeitas` field names.

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 return-value burden, and it does so by enumerating the normalized manifest fields and the server instructions plus derived signals. Combined with the caching and error notes, an agent has enough to call and interpret it; deeper structural detail of the returned payload is the only omission.

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?

Schema description coverage is 100%, so both parameters (id and retry_key) are already documented in the schema, including the `Anuncio.id` provenance. The description adds nothing about parameter syntax or format, so the baseline of 3 applies.

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-and-resource: it returns 'the tools and instructions a remote MCP server announced at its last check', then enumerates the normalized fields. That distinguishes it from get_listing, listing_status and listing_history, which cover other listing facets. The opening fragment is slightly elliptical (the return verb is implied rather than stated), but the content 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?

Usage is strongly implied: you read this to inspect the tool manifest a server announced, and the '404 tools_not_read when the server was not read yet' note tells the agent when there is nothing to fetch. However it never states when to prefer this over siblings such as get_listing, listing_history or listing_security, and there are no explicit exclusions.

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