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

No annotations are provided, so the description carries the full behavioral burden. It discloses the upstream source (crt.sh), which is useful, but says nothing about authentication requirements despite an access_token parameter, nothing about crt.sh rate limits or timeouts, and nothing about result volume or ordering.

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?

A single dense sentence that front-loads the resource and source and then enumerates returned fields. No filler and no repetition of the tool name.

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 and no annotations, the description does list the returned fields, which is a genuine plus. However, it omits auth prerequisites for access_token and any operational caveats about the crt.sh backend, leaving an agent under-informed for a two-parameter network-backed 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 50%: access_token is documented in the schema, but domain is bare. The phrase "for a domain" adds only a minimal hint that the parameter takes a hostname, and access_token is never explained in the description. This roughly fills the uncovered gap but adds little 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?

The description names a specific resource (active TLS certificates for a domain), the data source (Certificate Transparency logs via crt.sh), and the fields returned (issuers, names, validity dates). None of the siblings (domain_age, domain_trust_report, email_domain_check) do this, so it is easily discriminated. It lacks an explicit verb, which keeps it just below a 5.

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?

There is no statement of when to use this tool versus domain_trust_report or domain_age, and no exclusions. Nothing explains what "active" means (e.g. not yet expired vs. currently in CT), so the agent must infer the trigger conditions.

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