crtsh_searchDiscover subdomains for a domain by querying crt.sh certificate transparency logs. Provide a domain and receive a list of associated subdomains.
Discover subdomains via certificate transparency logs (crt.sh).
| Name | Required | Description | Default |
|---|---|---|---|
| limit | No | ||
| domain | Yes |
| Name | Required | Description | Default |
|---|---|---|---|
| result | Yes |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly, openWorld, idempotent, and non-destructive behavior. The description adds the external crt.sh source but does not disclose potential rate limits, data freshness, wildcard certificate behavior, or other operational nuances. It does not contradict the annotations.
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 a single front-loaded sentence with no filler. Every word earns its place by conveying action, target, and source.
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?
The tool is low-complexity with strong annotations and an output schema, so the short description plus structured data is mostly sufficient. The main gap is the lack of explicit usage routing and limit semantics, but the overall definition remains adequate for correct invocation.
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 0%, and the description gives no explicit meaning for 'domain' or 'limit'. The phrase 'Discover subdomains' only weakly implies that 'domain' is the target, and 'limit' is entirely unexplained, leaving the agent to rely on the bare schema properties.
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 states a specific verb ('Discover'), a clear resource ('subdomains'), and a precise method/source ('via certificate transparency logs (crt.sh)'). This distinguishes it from siblings like dns_lookup or dns_lookup_all by making the passive CT-log approach explicit.
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 implies the tool is for subdomain discovery through CT logs, but it does not explicitly say when to choose it over alternatives such as dns_lookup_all or hackertarget_hostsearch, nor does it mention when not to use it. Usage context is present but only by implication.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.