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

The description discloses meaningful behavioral details beyond annotations: it is a paid call ($0.01 USDC), uses public CT logs and a live HTTPS HEAD request, and returns specific fields. It also clarifies this is a read-only fact-gathering operation, consistent with readOnlyHint.

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 front-loaded with the most essential facts: cost, purpose, and returned fields. It is slightly dense with the payment address and multiple clauses, but every sentence carries useful information.

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 a single parameter, no output schema, and read-only annotation, the description covers the core knowledge an agent needs: what it does, what it returns, its scope limits, and its cost. It could be more complete by stating error cases or SLA details, but those are not critical for a simple single-host lookup.

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 coverage is 100%, and the host parameter is already described as a public DNS hostname, not a URL or IP. The description reinforces that it applies to a public hostname but does not add new parameter-level detail beyond the schema.

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?

Description clearly states the tool's function: TLS certificate facts for a public hostname, including a concrete list of returned fields. It differentiates itself from the sibling /domain dossier by explicitly saying it is not the full dossier, making the purpose unmistakable.

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 gives good context: use for lightweight TLS cert facts on a public hostname, not for a full domain dossier. It names the boundary with the domain tool implicitly, though it does not explicitly say 'use domain instead for full details'.

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