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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, and the description's 'no side effects' largely restates them. It does add provenance context — that this is an aggregation of daily-collected observatory data — which explains why the trend data is daily-grained, but pagination behavior and limits are only lightly implied.

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?

One dense paragraph with scope, ordering, paging, provenance and the sibling routing all front-loaded. Every clause carries information, though the em-dash-clause structure is slightly compressed for a single sentence.

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?

An output schema exists, so return values need no full explanation, yet the description still signals rank and stars gained. Combined with the day-range bound and paging guidance, an agent has everything needed to call it correctly.

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 0%, so the description must carry the params, and it does: 'days' is bounded (1-100) — a bound the schema does not state — and 'limit/offset' is explained as paging through the list. It compensates well, though it doesn't state defaults or format for the offset semantics beyond 'page through'.

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 the specific resource (repositories on GitHub Trending), the scope (last N days), the ordering (newest first) and the returned fields (rank, stars gained today). It also names the sibling get_leaderboard as the contrasting tool, so an agent can distinguish them without opening schemas.

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?

Gives an explicit trigger ('Use when the user asks what is trending on GitHub') and an explicit alternative with the condition that selects it ('For a project ranking by measured change use get_leaderboard instead'). Nothing is left to inference.

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