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

No annotations are present, so the description carries the full burden, but it only says 'Parse owner and repo' without disclosing behavior for invalid URLs, the output format, or that many input parameters are 'discarded after the shape check' as noted in the schema. The description also doesn't clarify that the `url` parameter is the intended input, leaving behavioral ambiguity.

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 concise sentence with no filler, and the core action is front-loaded. It could have included brief guidance on the expected parameter or output without losing conciseness, so it doesn't earn a 5.

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?

For a tool with nine parameters, no output schema, and no annotations, a one-sentence purpose statement is insufficient for correct invocation. The description doesn't specify which parameter receives the GitHub URL, what the parsed owner/repo output looks like, or how errors are handled, leaving substantial gaps.

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 description coverage is 100%, so the baseline is 3; the description adds no parameter-level detail beyond the purpose. It fails to identify which of the nine parameters should be used for the GitHub URL, and the schema's `url` description says 'HTTPS URL to normalize or cite' without mentioning GitHub, so the mapping is left to inference.

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 'Parse owner and repo from a GitHub URL' uses a specific verb and resource, clearly identifying the tool's core function. It aligns with the tool's name and distinguishes it from sibling shape tools by its GitHub-specific scope, though it does not explicitly name alternatives.

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 tool should be used when a GitHub URL needs parsing, but it provides no explicit when-to-use or alternative routing. With many sibling tools like figma-url-shape and jira-key-shape, the shared 'shape' pattern is implied but not stated.

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