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

With readOnlyHint, openWorldHint, idempotentHint, and destructiveHint all already declared, the bar is lower. The description adds genuinely useful behavior beyond those annotations: it re-fetches the live feed each call and may fail if the release has scrolled off the current window. This meaningful extra context earns a 4.

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 contain all the essential information with zero filler. The core purpose is front-loaded, and the behavioral caveat follows naturally. Every word contributes value.

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 single-parameter, read-only, idempotent tool with a strong annotation set and no output schema, the description fully covers the invocation context: what it fetches, where the URL comes from, and when it might fail. Nothing essential 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 schema already provides 100% coverage for the single url parameter, so the baseline is 3. The description adds specificity by stating the URL must come from one of the two named sibling tools and by warning about the live-feed limitation, enriching the meaning beyond the schema entry.

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 action ('Fetch one specific PR Newswire release'), the specific resource (by its URL), and the source domain. It also names the two sibling tools that produce the URLs, which distinguishes it from the list/search siblings.

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 explicitly anchors usage to URLs returned by prnewswire_latest_releases or prnewswire_search_releases, giving clear context for when to call it. The '~20-item window' caveat effectively warns when it will not succeed. It doesn't explicitly list exclusions, but the guidance is strong enough.

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