MCP Java Decompiler Server

Overview Schema Source Related Servers Discussions Admin

decompile-from-package

Decompile a Java class from its fully qualified package name, optionally providing classpath directories to search. Get readable source code from bytecode for inspection.

Instructions

Decompiles a Java class from a package name

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": {
      "packageName": "<packageName>"
    },
    "name": "decompile-from-package"
  }
}

Input Schema

Name	Required	Description	Default
`classpath`	No	Array of classpath directories to search
`packageName`	Yes	Fully qualified Java package and class name

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.2.4Jul 31, 2026

TDQS

B3.4/5.0

Behavior2/5

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

With no annotations provided, the description must disclose behavioral traits, but it only states the basic action without detailing return values, side effects, classpath resolution behavior, error conditions, or whether the operation is read-only. This is minimal disclosure beyond the one-sentence purpose.

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 a single, tightly crafted sentence that conveys the essential purpose without any filler or repetition. It is front-loaded with the action and object, making it highly scannable.

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?

Given the absence of annotations and output schema, the description is insufficiently complete. It does not explain what the decompilation returns, how the classpath is used, or how this tool differs behaviorally from siblings, leaving significant gaps for an agent deciding whether and how to use it.

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

Parameters3/5

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

Schema coverage is 100% with descriptive text for both packageName and classpath, so the schema already fully explains the parameters. The description adds no extra meaning about parameter semantics, making the baseline score appropriate.

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?

The description clearly states the action ('Decompiles') and the resource ('a Java class from a package name'), immediately distinguishing it from sibling tools that decompile from paths or JARs. The specific phrase 'from a package name' conveys the exact scope of the tool.

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

Usage Guidelines3/5

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

The description implies usage when the input is a fully-qualified Java package/class name, but it does not explicitly mention when to choose this tool over decompile-from-path or decompile-from-jar, nor does it provide exclusions or alternative recommendations. The schema clarifies parameter format but not selection criteria.

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

Deploy Server