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

With no annotations provided, the description carries full behavioral disclosure. It reveals query sources (crt.sh first, certspotter fallback), limitations (cap at 100 subdomains), timeout (10s), and return structure. This is thorough and goes beyond what annotations would typically provide.

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 compact and every sentence contributes value: purpose, usage, behavior, constraints, and return format. It is not padded with filler, and the most important information is front-loaded.

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 single-parameter tool with no output schema, the description provides enough operational context: what it does, how it works, its limits, and the shape of its result. It effectively covers the essential aspects a caller needs to know.

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?

The schema already provides a detailed description for the 'domain' parameter (public FQDN, resolvable, rejects IPs/ports/paths/protocols). The tool description does not add additional parameter-specific insight, but 100% schema coverage means the baseline of 3 is appropriate.

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 action: 'Discover subdomains visible in Certificate Transparency logs.' It uses a specific verb and resource, and differentiates itself from the broader dossier_full tool by calling itself the 'Core dossier check' for CT logs.

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?

Explicitly states when to use it ('for attack-surface mapping') and provides an alternative ('prefer dossier_full when running a complete audit'). This gives clear guidance on selection among sibling tools.

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