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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, open-world). The description adds genuine context beyond them: the return fields (headline, issuer, published time, excerpt, industry tags), the newest-first ordering, and the ~20-item cap, which is valuable since there is no output 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?

Three sentences, front-loaded with source and content, then return fields, then scope limit. Every clause earns its place with no redundancy.

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-param read tool with full schema documentation, full annotation coverage and no output schema, the description supplies the missing return-shape and scope details. Only the explicit sibling routing (search vs. get) is left implicit, keeping it short of perfect.

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 (limit, since_hours) are already documented with defaults and ranges. The description reinforces the ~20 cap and newest-first ordering but adds no syntax or format detail beyond what the schema provides, so the baseline of 3 applies.

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 ('Latest press releases from PRWeb's site-wide RSS feed') and identifies the source. The closing clause 'not PRWeb's full archive' crisply separates this feed tool from prweb_search_releases and prweb_get_release, so an agent can route without opening the schema.

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?

Usage is only implied: 'newest first' and 'not PRWeb's full archive' hint that this is for recent/site-wide monitoring rather than targeted lookup, but no alternative is named and no when-not condition is stated. Adequate but leaves the agent to infer the sibling choice.

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