Launches an active ZAP vulnerability scan against an in-scope URL to send attack traffic and uncover security flaws. Use it during an authorized testing window to validate web app weaknesses.
Start a ZAP active scan against an in-scope URL (attack traffic; respect the testing window).
| Name | Required | Description | Default |
|---|---|---|---|
| url | Yes |
Changes observed during successful MCP inspections.
v0.4.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden. It does usefully flag that this generates attack traffic and is bound by a testing window, warning of intrusiveness, but it omits that the scan is asynchronous and produces a scan ID that must be polled via pentest_zap_scan_status, and says nothing about auth or rate considerations.
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 tight sentence with the action front-loaded and the risk caveat in a parenthetical. Nothing is wasted, though the parenthetical is terse enough to border on cryptic.
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?
For a long-running, intrusive scan with no output schema and no annotations, the description is thin: it does not explain the asynchronous job model, how results are retrieved, or where findings end up. An agent could invoke it correctly but would not know what to do with the result.
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?
The single url parameter has 0% schema description coverage, so the description must compensate. Saying the URL must be "in-scope" adds a real constraint beyond the bare string type, but it does not clarify format (full URL vs host, scheme, path) or what happens if scope fails.
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 and resource ("Start a ZAP active scan") and names the target type (in-scope URL), which separates it from passive-crawl siblings like pentest_zap_spider. It does not explicitly name the sibling it differs from, so it lands at 4 rather than 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?
The description establishes two preconditions: the URL must be in scope and the testing window must be respected. However, it never says what to do first (e.g., run pentest_scope_check or spider) or when an active scan is inappropriate versus a lighter alternative.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.