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

Annotations already cover read-only, idempotent, closed-world safety, so the description's job is narrower and it delivers: it discloses the AND-matching rule ("Every word must match") and the result ordering (relevance, then stars), both non-obvious behaviors. It says nothing about empty-result behavior or how many results a broad query may return, which is the remaining gap.

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 short sentences, zero filler. The core action is front-loaded in sentence one, with matching semantics and ordering following in priority order.

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 3-parameter search tool with full schema coverage, annotations, and an output schema, the description covers what it searches, the match rule, and the sort order — everything needed to call it correctly. Only the query-language-filter interaction is left unresolved.

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?

With 100% schema coverage the baseline is 3, but the description genuinely adds meaning by naming which fields the query matches against — information absent from the schema. Minor ambiguity: it lists "language" as a query-matched field while a separate language filter parameter exists, which could confuse an agent about which one to use.

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 ("Find tracked repos") and enumerates the searchable fields (name, description, topics, language). It is clear enough to distinguish from get_repo (single-repo lookup) by implication, but it never names a sibling the way a top-scoring definition would.

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 implied by "Find tracked repos by words...", so an agent can infer this is the discovery path versus get_repo/get_trending. However, no explicit when-to-use/when-not-to-use guidance or alternative routing (e.g., prefer get_repo when you already know the repo) is given.

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