@stg0512/java-quality-mcp

A Model Context Protocol server that enforces Java code quality inside Claude Code. It runs Checkstyle + PMD on AI-generated code, detects design smell, and lets teams accumulate custom style samples that guide future generation.

Features

Layer 1 — Style & rule validation

• Checkstyle: naming conventions, method length, parameter count, nesting depth, cyclomatic complexity
• PMD quickstart: empty catch blocks, generic exception handling, string comparison order, and more
• Claude calls validate_code after generating code, fixes violations before showing output

Layer 2 — Design hints

• Structural analysis runs alongside linting and returns a design_hints field
• Detects: long if-else chains → Strategy/CoR, instanceof chains → Strategy/Visitor, sequential guard clauses → CoR
• Hints describe structural facts; Claude decides whether and how to refactor

Layer 3 — Team style samples

• /code-flavor-good and /code-flavor-bad slash commands
• Paste a code snippet → Claude extracts intent and tags → stored in local SQLite
• Samples are returned with every get_style_context call, shaping future generation

Requirements

• Node.js 18+
• Java 8+

Setup

Add to your .mcp.json:

{
  "mcpServers": {
    "code-quality": {
      "command": "npx",
      "args": ["@stg0512/java-quality-mcp"]
    }
  }
}

If java is not on your PATH, specify the JDK location:

{
  "mcpServers": {
    "code-quality": {
      "command": "npx",
      "args": ["@stg0512/java-quality-mcp"],
      "env": {
        "JAVA_HOME": "/path/to/jdk"
      }
    }
  }
}

Java is resolved in this order: JAVA11_HOME → JAVA_HOME → java in PATH.

Tools

| Tool | When to call | |---|---| | get_style_context | Before generating Java code — returns active rules + style samples | | validate_code | After generating Java code — returns violations + design_hints | | flavor_add | Record a good or bad code sample | | flavor_list | List recorded samples | | flavor_delete | Remove a sample by id | | get_quality_report | Generate a statistics report of accumulated validation data |

Slash commands

/code-flavor-good and /code-flavor-bad — paste a code snippet and Claude will analyze it, generate a note and tags, and save it automatically.

/quality-report — generates a quality statistics report including:

• Total validations and violations caught
• Overall first-pass rate
• Top 5 most frequently violated rules
• Pass rate trend: recent 7 days vs previous 7 days
• Total design hints triggered

Data storage

All data is stored in ~/.code-quality-mcp/flavor.db (SQLite), persisting across sessions:

| Table | Contents | |---|---| | flavors | Style samples recorded via /code-flavor-good and /code-flavor-bad | | validations | Auto-recorded results of every validate_code call (for quality reporting) |

License

MIT