Hercules MCP

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ctf_steghide

Inspect or extract hidden data from steghide-embedded files, with optional passphrase and custom arguments for CTF challenges.

Instructions

Purpose: Inspect or extract steghide payloads with action=info|extract. Constraints: Pass filepath and optional passphrase. Without a passphrase Hercules passes an empty one to avoid an interactive prompt. extra_args can tune steghide behavior. Example: ctf_steghide(action='info', filepath='/opt/workspace/image.jpg')

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": {
      "action": "<action>",
      "filepath": "<filepath>"
    },
    "name": "ctf_steghide"
  }
}

Input Schema

Name	Required	Description	Default
`action`	Yes
`filepath`	Yes
`extra_args`	No
`passphrase`	No

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Aug 8, 2026

TDQS

A3.9/5.0

Behavior3/5

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

The description reveals a key behavioral trait: without a passphrase, Hercules passes an empty one to avoid an interactive prompt. This is valuable context, but it does not disclose potential side effects of 'extract' (e.g., writing files to disk) or other operational nuances. Since no annotations exist, the description carries the full burden and could be more thorough.

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?

The description is extremely concise and well-structured: a 'Purpose' line, a 'Constraints' line, and an 'Example'. Every sentence earns its place, front-loading intent and providing a practical illustration.

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

Completeness4/5

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

For a tool with 4 parameters and an output schema, the description covers essential usage. It gives an example and explains passphrase handling. It does not mention output format, but the output schema presumably covers that. It is sufficient for an agent to invoke it correctly.

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

Parameters4/5

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

With 0% schema description coverage, the description compensates well: it explains the meaning of 'action' (info|extract), the requirement for 'filepath', the default behavior of 'passphrase', and the role of 'extra_args'. The example further clarifies usage.

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

Purpose4/5

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

The description clearly states the tool's purpose: 'Inspect or extract steghide payloads' with explicit action values (info|extract). It uses a specific verb and resource, making it distinct from generic tools, though it does not explicitly contrast with sibling tools like ctf_binwalk.

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?

Usage guidance is clear: required filepath, optional passphrase, and the behavior of using an empty passphrase to avoid interactive prompts. It also mentions extra_args for tuning. However, it does not state when to prefer this tool over alternatives or provide exclusions.

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