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

This tool has annotations (readOnlyHint, openWorldHint, idempotentHint) that already declare its safe, read-only nature. The description adds valuable behavioral context beyond annotations: it specifies the output fields, ordering, and the limit of ~20 releases, and clarifies the source (site-wide RSS feed) and scope limitation. This transparency helps the agent set expectations without needing to inspect the schema or make a test call.

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 description is two sentences long, front-loads the primary purpose and source, then details the return fields and ordering, and closes with an important scope caveat. Every clause adds necessary information with no filler, making it easy for an agent to parse quickly.

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 simple, read-only list tool with no output schema, the description is complete enough. It covers the source, scope, ordering, fields, and the ~20-release limit, while the schema handles parameter semantics. Nothing an agent needs to know to invoke the tool correctly or interpret basic results is missing.

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 input schema has 100% parameter description coverage, so the schema already documents the meaning of 'limit' and 'since_hours' thoroughly. The description adds no new parameter semantics beyond implying that the tool returns a limited set of recent releases. Per the rubric, when schema coverage is high, a score of 3 is appropriate; the description does not need to compensate.

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 clearly states the tool returns latest press releases from PR Newswire's site-wide RSS feed, lists the specific fields returned (headline, issuer, published time, excerpt, industry tags), and emphasizes 'newest first'. It also distinguishes itself from other PR Newswire tools by noting it covers only the ~20 most recent releases across all categories and not the full archive, making its scope 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?

The description implies when to use this tool: when you need the most recent press releases across all categories from the site-wide RSS feed. The phrase 'not PR Newswire's full archive' hints that for broader or historical queries, other tools (like search or get release) are appropriate. While it doesn't explicitly name alternatives, the contrast with 'full archive' provides clear context and exclusion.

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