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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and closed-world, so the safety profile is covered. The description adds real value beyond that: it states the return is metadata only, never file contents, never an assessment of the domain or operator, and pre-empts misreading 'not observed' as a judgment about the domain. It does not mention auth or rate limits.

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?

Three sentences, front-loaded with what the tool returns, followed by output-scope limits and a caveat about the meaning of a negative result. Every sentence carries information, though the opening sentence is long and packs four distinct facts into one clause chain.

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?

There is no output schema, so the description carries the burden of describing the return — and it does, listing sealed day, requested files, and cadence. Combined with the explicit statement that no file contents or judgments are returned, an agent has enough to call it correctly; only error/edge behavior (invalid domain, subdomain) is unaddressed.

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?

Only one parameter exists and schema description coverage is 100%, including the note that a pasted URL is accepted. The description adds no additional semantics about the domain argument (normalization, subdomain handling, IDN), so the schema does the work and the baseline of 3 applies.

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 names a specific verb and resource — answering whether this archive observes a given domain — and enumerates the dimensions of the answer (sealed day, requested machine-readable files, cadence). It is unambiguous about what the tool does, but it never references or contrasts with siblings like capture_status or suggest_domain, so an agent gets no explicit routing signal.

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?

Usage is implied: this is the lookup to run when you want to know if a domain is in the archive. There is no explicit when-to-use/when-not guidance and no named alternative (e.g., suggest_domain for unobserved domains, order_capture to add one), so the agent must infer routing from sibling names alone.

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