amass_passive_discoveryDiscover in-scope subdomains passively via Amass enumeration without active scanning.
Run the explicitly enabled Amass passive enumeration mode and retain only in-scope subdomains.
| Name | Required | Description | Default |
|---|---|---|---|
| domain | Yes |
| Name | Required | Description | Default |
|---|---|---|---|
| count | Yes | ||
| domain | Yes | ||
| subdomains | Yes |
Changes observed during successful MCP inspections.
v2.2.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description adds two useful behavioral facts beyond them: the mode must be 'explicitly enabled' and results are filtered to in-scope subdomains. It still omits auth requirements, rate limits, or data-source 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?
A single tight sentence with the action front-loaded and no filler. Appropriately sized for a one-parameter tool, though it leaves room that could have carried usage or parameter detail.
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?
Complexity is low, an output schema exists so return values need no explanation, and annotations cover safety. What remains missing is the meaning of the 'domain' input and any routing against the competing discovery siblings, leaving the definition adequate but not complete.
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?
One parameter at 0% schema coverage: 'domain' is typed but entirely undocumented in the schema. The description never states that this parameter is the target root domain to enumerate, so it fails to compensate for the coverage gap even for a single obvious-looking input.
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 and resource ('Run the explicitly enabled Amass passive enumeration mode') and adds the output scope ('retain only in-scope subdomains'). Naming Amass implicitly separates it from subfinder_discovery/assetfinder_discovery, but it never explicitly routes against subdomain_enumeration or dns_enumeration, so it stops short of full sibling differentiation.
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 word 'passive' implies the when-to-use condition (non-intrusive enumeration with no direct target interaction), which is meaningful when choosing among the many subdomain-discovery siblings. However, no alternative is named and no explicit when/when-not rule is given, so the guidance remains implied rather than stated.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.