code.repo-lookup

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

With no annotations provided, the description fully discloses behavioral traits: it is a read-only lookup (implied by 'look up'), returns specific data, and has rate limits. No destructive behavior is suggested, but error handling or response format is not mentioned, which is acceptable for a simple lookup.

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 two concise sentences: the first clearly states the action and output, the second adds the rate limit. No unnecessary words or repetition.

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 simple one-parameter, no-output-schema tool, the description provides all essential information: what it does, what it returns, and the rate limit. It does not specify error behavior or format requirements, which are minor gaps but acceptable for a lookup tool.

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 input schema has 100% description coverage for the single parameter 'repo', with a clear description 'GitHub "owner/name" slug.' The tool description adds no further parameter meaning, so a baseline of 3 is appropriate.

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 states a specific action (look up a public GitHub repository by owner/name) and enumerates returned fields (description, language, topics, etc.), distinguishing it from any sibling tool which are unrelated.

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 provides clear context by specifying the rate limit (60 req/hr/IP unauthenticated), which guides usage. It does not explicitly exclude scenarios or name alternatives, but the single-purpose nature makes this less critical.

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