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

Adds useful behavioral details beyond annotations: returns headline, published time, and sub-headline excerpt; orders newest first; caps at 50 releases. Annotations already declare read-only, idempotent, and non-destructive, so the description enriches the safety profile with output composition and scope. No contradiction.

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?

Two sentences with no filler. Purpose is front-loaded, scope and limitations are stated immediately, and every clause adds value. A model of conciseness for a simple read-only tool.

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 two-parameter read-only tool with no output schema, the description covers the return fields, ordering, and coverage limit. Annotations handle safety. It omits explicit error/empty-response behavior, but for this simple feed tool that is a minor gap, not enough to lower further.

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%, with both parameters (limit, since_hours) fully described in the schema. The description does not add any parameter-specific meaning beyond what is already structured, so the baseline of 3 is appropriate.

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 ('Returns') and resource ('latest press releases from Newswire.com's public newsroom RSS feed'). Clearly defines scope ('50 most recent releases') and distinguishes from full-archive search by explicitly noting 'not Newswire.com's full archive'. This differentiates it from sibling search tools even without naming them.

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?

Provides clear context: this is for recent releases only, newest first, limited to 50. The 'not full archive' exclusion implies that for older or broader searches the agent should look elsewhere, but it does not explicitly name alternatives like newswire_com_search_releases. Clear usage context, but no direct when-to-use/when-not-to-use routing.

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