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

Goes well beyond the annotations: caps of 50 items and 2 MB, lenient parsing, a 422 for non-feed pages that is uncharged, pricing and free-tier rules, and the explicit note that repeats are not free (consistent with idempotentHint=false). The 'reads or computes only and changes nothing' statement aligns with readOnlyHint=true rather than contradicting it.

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-loads what the tool returns, then limits, failure behavior, use cases, and pricing in a sensible order. The opening sentence is long and packs return fields into a run-on list, but no sentence is wasted.

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 fully specifies the response shape and field formats (ISO 8601 dates, plain-text summaries). Size limits, error behavior, and cost are all covered, so an agent has everything needed to call it correctly.

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 both parameters are already documented, including the web-page-that-links-to-a-feed case. The description adds only the item cap and an example URL, so it stays at the baseline for a fully documented 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?

States a specific verb and resource ('Read a public RSS 2.0, RSS 1.0 or Atom feed') and enumerates the returned fields (title, link, date, summary, author, id). This clearly separates it from sibling page-scraping tools like extract, contents, or url_meta.

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?

Gives concrete when-to-use guidance ('follow news, blogs, release notes or podcasts without scraping pages') and a worked example URL. It implies the alternative (page scraping) but does not name a specific sibling tool to use instead in edge cases, such as when the URL is not a feed.

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