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

With no annotations, the description fully carries the transparency burden. It discloses that all 10 checks fire concurrently, the transport methods (Cloudflare DoH or direct HTTPS), the 5-second per-check timeout, the paywall call counting, and the exact return structure (JSON keyed by check id with a CheckResult discriminated union). This goes far beyond a minimal safety disclosure.

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 front-loaded with the core action, then provides usage guidance, operational details, and return format in a logical sequence. Each of the five sentences contributes unique information, with no filler or redundancy. It is dense but highly efficient.

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?

Given the tool's moderate complexity (one parameter, no output schema, no annotations), the description is remarkably complete. It covers purpose, usage, alternatives, concurrency, timeout, paywall implications, and return format. A lack of an output schema is compensated by the explicit JSON structure description.

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% for the single 'domain' parameter, which already documents the FQDN requirement and what is rejected (IPs, ports, paths, protocol prefixes). The tool description adds no additional parameter-level context, so the baseline score 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 opens with 'Aggregate dossier check: Run all 10 Domain Dossier checks' and explicitly lists the 10 checks (dns, mx, spf, dmarc, dkim, tls, redirects, headers, cors, web-surface). This clearly distinguishes the tool from the individual dossier_* siblings by its aggregate nature and parallel execution.

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?

The description explicitly states when to use this tool ('Use when you need a comprehensive domain health snapshot in one call') and when not to use it ('For a single focused check, prefer the individual dossier_* tools to minimise latency'). It also adds the paywall-count benefit, giving concrete decision criteria.

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