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

With no annotations, the description carries the behavioral burden. It communicates the core parse behavior, but it doesn't state whether invalid URLs error or how the parsed result is returned, nor does it note that unrelated schema fields 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?

A single sentence with no filler. The verb, input, and output are front-loaded and nothing in the description is wasted.

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?

The description is adequate for a simple parser but leaves gaps: there is no output schema, so the return value is not formally described; no annotations cover safety; and the schema's nine optional fields make it unclear which are used. The tool name and description compensate enough to be usable, but not fully complete.

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 a baseline of 3 applies. The tool description adds GitHub-specific intent to the generic 'url' parameter, but it doesn't explicitly mark url as the required logical input or clarify which of the 9 optional properties are relevant.

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'), the resource ('GitHub URL'), and the expected result ('owner and repo'). It cleanly distinguishes this tool from sibling shape tools such as domain-shape, figma-url-shape, and jira-key-shape.

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: use this tool when a GitHub URL needs to be reduced to owner/repo. It doesn't explicitly name alternatives/exclusions, but the use case is concrete enough that an agent can route to it without much inference.

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