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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so safety is covered. The description adds useful non-obvious behavior: ordering by recency vs relevance, keyset vs offset paging, and an indexing disclaimer. That value is diluted because the paging and ordering rules reference parameters (`q`, `next_cursor`) absent from the schema.

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?

The core capabilities lead, but there is filler: 'the question a reader or an agent actually asks' and the closing 'We index and link; the feeds belong to whoever publishes them' add no operational information. Roughly one third of the text is rhetorical rather than directive.

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?

With no output schema, the description should clarify the response shape, yet it only says 'answers with every feed.' Worse, it describes a filtering/paging interface the 3-parameter schema cannot express, leaving the agent unable to reconcile the description with what it can actually send.

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 coverage is 100% and each of the three real parameters (dominio, api_pass, retry_key) is documented in the schema itself, so the baseline would be 3. The description adds no meaning for any of them and instead describes filters, `q`, and `next_cursor` that do not exist in the schema, actively confusing the agent about what it can pass.

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 opening question ('Does this site publish a feed?') plus 'Answers with every feed known for a domain' names a specific resource (feeds) and scope (per domain), so the agent knows what it returns. It does not explicitly differentiate itself from close siblings like feed_search or feed_posts, so it stays below a 5.

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 does give conditional usage ('without q ... with q ...') and describes ordering and paging modes, which is real guidance. However, it never states when to prefer feed_find over feed_search/feed_posts, and the conditions hinge on a `q` parameter that the schema does not expose, so the routing advice is muddled.

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