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

Beyond the readOnly/openWorld/idempotent annotations, it discloses pagination depth (30 a page, up to 10 pages), sort order, the exact fields returned, and that it runs on GitHub's search with roughly 30 searches/minute. The cost and rate-limit disclosure is exactly the kind of context annotations cannot carry.

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 the resource and ordering, then filtering, then cost. Slightly redundant where it repeats the page size and state values already in the schema, but nothing is wasted overall.

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 compensates by listing the returned fields, and it covers pagination limits, sort order, filtering, and rate limits. An agent has everything needed to call this correctly and interpret the response.

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% and all four parameters are documented there, including the repo format and state enum. The description mostly restates those same constraints ('owner/name', open/closed/merged, 30 a page) rather than adding new semantics, so the baseline 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?

The description opens with a specific verb+resource ('Pull requests a developer opened') and immediately fixes scope and ordering ('newest first, 30 a page'). The enumeration of returned fields plus the note about 'projects they don't own' makes it clearly distinguishable from the commit-listing 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?

It gives an explicit use case ('see what they actually changed in projects they don't own') and states the two narrowing options (repo, state). It stops short of naming an alternative sibling (e.g. list_commits vs this) or stating when not to use it.

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