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

With no annotations provided, the description carries the full burden of behavioral disclosure. It reveals that the tool does NOT perform WHOIS or ownership lookups, which is useful, but it does not explain what happens with the diverse parameters (e.g., whether they are discarded, validated, or transformed) beyond what the schema already states. It also does not mention side effects, data usage, or return behavior. The disclosure is minimal and incomplete for a tool with 9 optional inputs.

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 that avoids fluff. It is front-loaded with the core action and constraint. However, its brevity comes at the cost of missing critical context, so while it is efficiently written, it is under-specified. It earns a 4 for conciseness but not for completeness.

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 9 optional parameters, no required parameters, no output schema, and no annotations, the description is severely inadequate. It does not explain the tool's overall behavior, how the parameters are used, what output is produced, or when to invoke it. An agent cannot determine correct usage, input expectations, or result interpretation from this description alone. It is completely insufficient for the tool's complexity.

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 meaning beyond what the schema already provides; it does not elaborate on how each parameter is used or what constitutes a valid shape. Since the schema covers parameter documentation, the description need not repeat it, but it also does not add value by clarifying relationships or constraints.

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 action 'Split a hostname into labels' which is clear for a hostname-focused tool, but the tool accepts 9 parameters spanning URLs, cities, feeds, JSON, paths, zones, and queries. It does not explain how these relate to splitting a hostname, making the overall purpose ambiguous and disconnected from the parameter set. The name 'domain-shape' also suggests a broader shape-checking role, but the description narrows it to hostname splitting without acknowledging the full scope.

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?

There is no guidance on when to use this tool versus its siblings like file-path-ok, jira-key-shape, or github-repo-shape. The description does not mention alternatives, exclusions, or conditions under which this tool is preferred. An agent would have no idea why to choose this over the many other shape-checking tools in the sibling list.

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