Look up a URLhaus malware-family signature and return counts plus a bounded list of associated URL and payload observations.
| Name | Required | Description | Default |
|---|---|---|---|
| limit | No | Maximum records to return (default 20, max 50). | |
| signature | Yes | Malware-family signature, 1-64 safe text characters. |
Changes observed during successful MCP inspections.
Input schema / properties / limit / maximumAdded value: +50Input schema / properties / limit / minimumAdded value: +1Input schema / properties / limit / typePrevious value: -"number"New value: +"integer"Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=true and destructiveHint=false, so the safety profile is covered. The description adds that results come back as counts plus a bounded list of URL and payload observations, which is modest but real context beyond 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?
A single front-loaded sentence with no filler: action, resource, then return shape. It earns its place, though it stops just short of the routing information that would make it maximally useful.
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?
There is no output schema, and the description does give a rough return sketch (counts plus bounded URL/payload observations), which is the main thing it needs to supply. It omits what happens with an unknown or malformed signature and how the "bounded" limit interacts with the returned observations.
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 100%: the schema documents both `signature` (1-64 safe text characters) and `limit` (default 20, max 50) with full constraints. The description adds only the word "bounded," so baseline 3 is appropriate – the schema carries this dimension.
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?
Specific verb ("Look up") plus a precise resource ("URLhaus malware-family signature"), and it even previews the return shape (counts plus URL/payload observations). The word "signature" implicitly separates it from sibling lookups keyed on host/url/tag/payload, but no sibling is named, so differentiation relies on inference.
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 never states when to choose this tool over urlhaus_lookup_host, urlhaus_lookup_tag, urlhaus_lookup_url, or urlhaus_lookup_payload, and gives no exclusions or prerequisites. The only usable cue is the word "signature" in the description, which is no more than the name already conveys.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.