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

The readOnlyHint annotation already covers the safe, read-only nature of the tool. The description adds only the basic parsing behavior and does not disclose edge cases like invalid URLs or return format, but there is no contradiction with the annotation.

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 one short sentence with no filler. The core action and target resource are front-loaded, making it immediately scannable.

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 simple parse tool, the description conveys the primary input and output. However, it leaves ambiguity around the nine optional schema parameters and does not explain malformed-input behavior, and there is no output schema to fill that gap.

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?

With 100% schema description coverage, the baseline is 3. The description clarifies that the url parameter is expected to be a GitHub URL and that owner/repo are extracted, but it does not add substantial parameter-level detail beyond the schema.

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 uses a specific verb ('Parse') and a concrete resource ('owner and repo from a GitHub URL'), making the tool's core function clear. It is distinguishable 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?

Usage is implied: the tool should be used when the agent has a GitHub URL and needs to extract owner and repo. However, it does not explicitly state when not to use it or how it differs from related 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.