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

Annotations declare readOnly/idempotent/non-destructive, and the description layers on substantial extra context: capped at 40 posts, publication ordering, body excluded, this is our cached copy read on our own schedule rather than the live feed, `lido_em` records read time, and it returns an empty list when the feed has never been read.

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 and informative, but noticeably redundant: 'never a URL' and 'takes an id from this index' are each stated twice, and the body exclusion is repeated. Trimming those would tighten it without losing meaning.

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 carries the full burden and does so: it lists the returned fields, the 40-post cap, ordering, and the empty-list case, so an agent knows exactly what to expect from a call.

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%, so the baseline is 3, but the description adds real semantic guidance beyond the schema: the id must come from this index and must never be a URL, which is a common misuse it pre-empts.

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+resource (list the posts of one feed) and enumerates the returned fields (title, date, author, summary, categories, enclosure), explicitly excluding the body. It cleanly separates itself from feed_post (single body) and feed_find/feed_search (feed discovery).

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?

Explicitly instructs to find the feed first via feed_find or feed_search, and states the hard precondition that it accepts an index id, never a URL. It also names feed_post as the alternative when the body is needed.

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