Passively discover subdomains by querying public certificate transparency logs for a target domain, supporting authorized reconnaissance without active scanning.
Passively enumerate subdomains observed in public certificate transparency logs.
| Name | Required | Description | Default |
|---|---|---|---|
| domain | Yes |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden; it discloses the passive, CT-log-based nature, which is useful behavioral context. It omits limitations such as only covering domains with logged certificates, whether results are deduplicated, auth/rate limits, and output behavior.
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?
One front-loaded sentence with no filler. It states the action and source immediately.
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 no annotations, no output schema, and zero schema descriptions, the definition is under-specified. It does not explain return values, result completeness, or parameter expectations, leaving an agent to infer important details.
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 one parameter, 'domain', and schema description coverage is 0%, so the description should compensate. It never explains what domain value is expected (apex domain? wildcard? hostname?) or how it is used.
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?
States a specific verb ('enumerate'), resource ('subdomains'), and data source ('public certificate transparency logs'), which differentiates it from active DNS siblings like dns_lookup. It does not explicitly name or compare against those siblings, so it stops short of 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?
No when-to-use or when-not-to-use guidance is given. The word 'passively' hints at context but does not tell an agent when to choose this over dns_lookup or other reconnaissance tools.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.