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

With no annotations provided, the description must carry the full behavioral disclosure burden. It only states the core splitting action and what it does not include; it doesn't mention that most inputs are discarded, whether validation errors occur, or what the result contains. The schema hints at discard behavior, but the tool description itself adds minimal transparency.

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 clear sentence with no wasted words, front-loading the action and scope. Given the tool's multiple parameters and discard behavior, the extreme brevity comes at the cost of missing useful context, but it is concise and well-formed.

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 8 parameters (many marked discarded), no output schema, and no annotations, the description is far too thin. It doesn't explain the meaning of 'shape', what the split returns, how to identify the correct parameter, or how discarded fields are handled. An agent would be under-informed when invoking this tool.

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?

All 8 parameters already have schema descriptions, so the baseline is 3. The tool description implies that 'host' is the relevant parameter, but the schema already calls it 'Public hostname'. No parameter-specific meaning is added 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 clearly states the specific action: split a hostname into labels, and explicitly excludes WHOIS or ownership data. This distinguishes it from sibling shape tools, though it doesn't name an alternative or describe the output format.

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?

No guidance is given on when to use this tool vs. siblings like github-repo-shape or jira-key-shape. The negative clause implies it cannot answer ownership questions, but it never says which tool would be appropriate for that need.

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