Checks a URL against URLhaus (abuse.ch), a public database of known malware distribution URLs. A clean result only means the URL is not listed, not that it is safe.
| Name | Required | Description | Default |
|---|---|---|---|
| url | Yes | URL to check against known phishing/malware URL databases. |
Changes observed during successful MCP inspections.
Input schema / properties / url / descriptionPrevious value: -""New value: +"URL to check against known phishing/malware URL databases."Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already provide readOnlyHint, openWorldHint, idempotentHint, and destructiveHint, covering safety and side effects. The description adds meaningful behavioral context beyond annotations by explicitly stating that a clean result does not imply safety, reinforcing the open-world nature and preventing over-reliance on a negative result.
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?
Two sentences with no filler. The action is front-loaded in the first sentence, and the second sentence adds an essential caveat. Every word earns its place.
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 simple, single-parameter, read-only lookup with comprehensive annotations, the description is nearly complete. It lacks explicit return format details, but the absence of an output schema is not a major gap given the simplicity and the clear caveat about result interpretation.
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 100% for the single 'url' parameter, which is described as 'URL to check against known phishing/malware URL databases.' The description adds the specific database (URLhaus) but does not introduce new semantics beyond what the schema conveys. Baseline 3 is appropriate.
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?
Description clearly states a specific verb ('checks'), resource ('URL'), and target database ('URLhaus (abuse.ch)'), immediately distinguishing it from siblings like ip_reputation or vulnerability_check. The caveat about clean results reinforces the specific scope.
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?
Usage is implied: an agent can infer when to use this tool (when a URL reputation check against URLhaus is needed), but there is no explicit guidance on when to prefer this over alternatives like security_scan or url_clean, nor exclusions. The description does state the interpretive caveat, but it is not about tool selection.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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