Skip to main content
Glama

entropy_map

Map windowed Shannon entropy across a binary to identify packed or encrypted regions and distinguish them from plaintext areas.

Instructions

Windowed Shannon entropy: packed/encrypted vs plaintext regions.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
pathYes
stepNo
windowNo

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observedv0.3.0

TDQS

C2.7/5.0
Behavior2/5

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

With no annotations and no output schema, the description carries the full behavioral burden and mostly drops it: it does not say what is returned (per-window entropy values? offsets? a verdict?), how large outputs scale with window/step, or whether it reads or mutates the target. Only the analytic intent is conveyed.

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

Conciseness4/5

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

A single front-loaded clause with no filler, which is appropriate for a short fragment. It is arguably under-specified rather than concise, but every word does work and nothing is buried.

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

Completeness2/5

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

For a 3-parameter tool with 0% schema coverage, no annotations, and no output schema, the description should at minimum explain the window/step semantics and the shape of the result. Neither is present, leaving the agent to guess how to drive the tool or interpret its output.

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

Parameters2/5

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

Schema description coverage is 0% for all 3 parameters, so the description must compensate and does so only for 'window' via the word 'Windowed'. The 'step' parameter (default null) and the required 'path' are given no meaning, format, or unit guidance anywhere.

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 names the technique (windowed Shannon entropy) and its analytic purpose (distinguishing packed/encrypted from plaintext regions), so an agent can tell what it computes. It does not, however, differentiate itself from adjacent tools like find_blobs or bin_info that can also reveal structure, and it never says what it operates on (a file path).

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

Usage Guidelines2/5

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

There is no when-to-use guidance, no prerequisites, and no mention of alternatives such as find_blobs, strings_scan, or yara_scan, which overlap in the 'find suspicious regions' space. The agent must infer that this is for triaging packed binaries.

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