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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds valuable behavioral context: it explains that associations are for organization, not routing, and details how PRs are matched to issues. This clarifies the semantic meaning of the output and a key execution nuance, exceeding what annotations provide.

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 three sentences, front-loaded with the core purpose in the first sentence. The second and third sentences add meaningful context about associations and PR matching without redundancy. Every sentence earns its place, making it concise and well-structured.

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 zero parameters, no output schema, and annotations covering safety, the description adequately explains what the tool returns (repositories and their projects) and the semantic meaning of associations. It also explains PR matching behavior. It is complete for a simple list tool, though it omits pagination or limits, which are minor and not always specified.

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 tool has zero parameters, so schema description coverage is trivially 100%. The description does not need to explain any parameters, and the baseline for 0 params is 4. It adds no parameter-specific info, but since there are none, it appropriately focuses on output semantics, which is acceptable.

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 clearly states the tool lists every GitHub repository the app is installed on for the workspace, along with associated projects. It distinguishes itself from siblings like link_github_repository and unlink_github_repository by focusing on listing rather than modification, and from list_issue_pull_requests by targeting repositories. The verb 'list' and specific resource make the purpose unambiguous.

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 gives clear context on when to use it (when needing repository info) and clarifies the meaning of associations, which helps interpret results. It does not explicitly mention alternatives or exclusions, but given the niche nature of this tool, the context is sufficient. There is no direct competing listing tool, so the lack of explicit 'instead of' is acceptable.

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