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

Annotations provide readOnlyHint and openWorldHint, but the description goes far beyond: it explains parallel execution, the per-check grading with severity levels, the fact that raw records and fix instructions are not returned, the exclusion of web/discovery checks, and the complete JSON response envelope with status variants (ok, not_applicable, timeout, error) and how to interpret them. This is rich behavioral disclosure with no contradiction.

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 dense but efficiently organized: purpose first, then usage guidance, then behavior and return format. It is longer than typical, but every sentence adds necessary information for a tool that produces complex graded output across nine checks. The structure front-loads the key action and the most critical exclusions.

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 no output schema, the description compensates by fully specifying the return structure: the top-level JSON fields, the per-check object shape, and the status envelope with all possible statuses and their meaning. It also clarifies what is not included (raw records, fix instructions, web checks) and the grading reference. An agent has all necessary information to invoke and interpret results correctly.

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?

There is only one parameter, domain, and the schema already describes it fully: 'Public domain name, e.g. example.com. IP addresses, ports, paths and protocol prefixes are rejected.' Since schema coverage is 100%, the description adds no additional parameter-specific meaning beyond the tool's overall purpose, so 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 explicitly states the tool runs nine specific DNS, email-authentication and TLS checks in parallel and returns graded lines. It names the checks individually, distinguishing it from the single dossier_* tools that provide raw data. This is a precise, actionable purpose.

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?

It gives explicit when-to-use guidance: 'Use it first when asked how a domain is set up or whether its email can be spoofed; then call the single dossier_* tool for any check you need the raw data for.' This clearly directs the agent to the summary for overview and to the specific tools for raw data, leaving no ambiguity.

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