Scan files against YARA rules to detect malware patterns, using inline rule text or a .yar path within allowed roots.
Scan a file with YARA rules (rule text, or a .yar path inside the allowed roots).
| Name | Required | Description | Default |
|---|---|---|---|
| ref | No | ||
| part | No | ||
| image | No | ||
| rules | No | ||
| local_path | No |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden. It hints at a 'allowed roots' path restriction, which is useful, but says nothing about whether the scan is read-only, what the match output looks like, or how ref/part/image select the target. For an unannotated tool this is a significant gap.
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 core operation front-loaded and no filler. Brevity is appropriate, though the parenthetical is doing work that belongs in parameter documentation.
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?
Five undocumented parameters, no annotations, and no output schema mean the description is the only source of guidance — and it covers roughly one parameter. The ref/part/image combination is central to how this tool targets data and is left completely unexplained.
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 0% across 5 parameters, so the description must compensate and does not. It addresses 'rules' (rule text or .yar path) and loosely the file target, but leaves ref, part, image, and local_path entirely undefined — an agent cannot tell how to point the scan at a disk image versus a filesystem path.
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 (scan) and resource (file) with the YARA rule mechanism, and no sibling tool competes in this space. It does not explicitly differentiate itself from the grep_* family, but the YARA-specific purpose is unambiguous.
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?
No guidance on when to use this over grep_files/grep_file/grep_unallocated, which are the natural alternatives for pattern matching. The parenthetical about rule text vs .yar path is a parameter detail, not a usage condition or exclusion.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.