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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the description is not required to explain safety. It adds value by describing the return contents (description, star count, language, last update timestamp) and the sorting behavior (relevance or metrics), which is behavioral context beyond the annotations.

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?

The description is compact and front-loaded, with the core action stated in the first phrase. It avoids redundancy and uses only two sentences to convey purpose, behavior, and use case, earning its place entirely.

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?

Given the tool's moderate complexity, the description provides sufficient context: it states the input (keywords), optional sort behavior, and the output fields. There is no output schema, so the description appropriately covers return values. It does not discuss pagination or limits beyond the schema, but the schema already documents max_results.

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%, with parameter descriptions already explaining query, sort, and max_results. The description only reinforces the concept of 'keywords' and 'metrics' without adding new parameter-level details, so it meets the baseline but does not exceed it.

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 uses a specific verb ('Search') and resource ('GitHub repositories') and clearly communicates the scope: finding repos by keywords, sorted by relevance or metrics. It distinguishes itself from sibling tools like compare_repos and get_repo_stats by focusing on discovery rather than analysis.

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 states when to use the tool ('Use for finding projects, libraries, or code samples related to specific topics'), giving clear context. It does not mention alternatives or exclusions, but the use case is sufficiently distinct from the sibling tools.

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