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

With no annotations, the description must carry the full burden of behavioral disclosure, but it only states the parse intent. It does not say whether the tool is read-only, whether it validates the URL, what happens for invalid input, whether it accesses the network, or whether all other schema parameters are ignored.

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 a single front-loaded sentence with no filler. Every word earns its place, and the core extraction behavior is stated immediately.

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?

This is an extraction tool with no output schema and no annotations, so the description should explain the return format and edge-case behavior, but it does not. With nine optional parameters and no mention of which one activates the tool, the description leaves the agent to infer the call pattern and expected result.

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 already 100%, so the baseline is 3, but the description adds meaningful semantics by clarifying that the 'url' parameter is a GitHub URL and that the result should be owner/repo. This is especially valuable because the schema's url description—'HTTPS URL to normalize or cite'—does not convey the GitHub-specific intent.

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 names a specific verb ('parse'), a specific input ('a GitHub URL') and a specific output ('owner and repo'), which clearly distinguishes this tool from sibling shape tools like figma-url-shape or jira-key-shape. It is a clear, non-tautological statement of purpose.

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 no explicit when-to-use guidance and names no alternatives or exclusions. An agent can only infer from the tool name and wording that this is for GitHub URLs, but the description does not help it choose between this tool and related URL/shape tools like normalize-url or domain-shape.

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