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

No annotations are provided, so the description carries the burden. The verb 'Parse' strongly implies a pure, non-mutating, read-only operation, which is good. However, the description does not disclose what happens with malformed URLs, whether any network access is involved, or how other optional schema parameters are handled. It therefore adds a basic behavioral signal but leaves meaningful uncertainty.

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?

A single eight-word sentence that front-loads the action, resource, and source. There is no filler or redundant phrasing; every word contributes to conveying the tool's purpose.

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?

With no output schema and no annotations, the description must supply enough context for correct invocation. It gives the extracted result ('owner and repo') but does not state the output format, exactly which of the nine optional parameters to set, or what happens on invalid input. The tool is simple enough that the core usage is inferable from 'Parse ... GitHub URL,' but an agent still lacks precise return and parameter selection information.

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 schema is fully described (100% coverage), so the baseline is 3. The description adds real value by clarifying that the 'url' parameter is expected to be a GitHub URL and that the result is the repository's owner and repo. This is more than the schema's generic 'HTTPS URL to normalize or cite' wording. It does not map other parameters, but for a parse tool the mapping of the URL is the critical information.

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 verb ('Parse'), a concrete resource ('owner and repo'), and the exact context ('a GitHub URL'). The GitHub-specific resource and extraction target distinguish it from sibling shape-check tools like figma-url-shape and jira-key-shape, so an agent can tell what it does without reading the schema.

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 implies the usage condition — a GitHub URL whose owner/repo need to be parsed — but it never explicitly states when to choose this tool over siblings, or when not to use it. No alternatives are named, so the guidance is only inferred from the singular description; this is acceptable but not explicit.

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