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yara_scan

Scan disk or memory images with custom YARA rules to locate IOC matches, webshells, or packer stubs. Returns match offsets.

Instructions

Sweep an evidence object (disk or memory image) with a YARA rule and return matches with offsets. rules_text is the YARA rule source. Use to hunt webshell signatures, packer stubs, or campaign IOCs across an image. Read-only.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "target": "<target>",
      "rules_text": "<rules_text>"
    },
    "name": "yara_scan"
  }
}

Input Schema

Name	Required	Description	Default
`target`	Yes
`rules_text`	Yes

Output Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Jun 14, 2026

TDQS

A3.6/5.0

Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Declares 'Read-only' and output format, but no annotations provided. Lacks details on parameter constraints (e.g., 'target' format, 'rules_text' validity) and error behavior.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences, 48 words. Front-loaded purpose and output, second sentence adds use cases and read-only flag. No redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Output schema exists, so return values are covered. However, parameter details are missing and no prerequisites or edge cases are described. Adequate but not thorough.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters1/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 0% and description only restates parameter names ('rules_text is the YARA rule source') without adding format, examples, or constraints.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

Clear verb 'sweep' and resource 'evidence object' with specific output 'matches with offsets'. Distinguishes from siblings like 'mem_cmdline' or 'fs_find' as it is dedicated to YARA scanning.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly states use cases: 'hunt webshell signatures, packer stubs, or campaign IOCs'. Does not mention when not to use or alternatives, but gives clear context.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.