qwen-dap-mcp

Give coding agents a real native debugger.

qwen-dap-mcp is a local Debug Adapter Protocol (DAP) → Model Context Protocol (MCP) bridge for native crash debugging, hang/deadlock triage, crash dumps, differential runtime analysis, remote targets, and bounded fix/verify workflows.

Built for Qwen Code, usable from any stdio MCP client, and designed to expose debugger evidence without turning MCP into a general-purpose shell.

Quick start · Capabilities · Debugger support · Safety · Docs · Contributing

Why this exists

Coding agents can read source and propose patches, but native failures often cannot be diagnosed reliably from source alone. The useful evidence lives at runtime: thread stacks, registers, locals, disassembly, exception state, modules, memory, wait states, symbols, and crash dumps.

qwen-dap-mcp makes that evidence available through MCP and adds agent-oriented workflows on top of raw debugger primitives:

• Evidence first — inspect the actual failing process instead of guessing from source.
• High-level workflows — crash, hang, differential, writer-tracing, dump, and verification tools are designed for agents rather than humans driving a debugger console.
• Bounded automation — autonomous fix/verify state is explicit, serializable, iteration-limited, and re-checks the original reproduction.
• Small default surface — the normal agent toolset stays compact while advanced low-level DAP tools remain opt-in.
• Local by default — the MCP server communicates over stdio and debugger adapters run locally unless you explicitly configure a validated remote target.

Quick start

Qwen Code

Install directly from GitHub:

qwen extensions install SLP-DEV1/qwen-dap-mcp

Or install the published npm package:

qwen extensions install @slp-dev1/qwen-dap-mcp

Then verify the extension:

/mcp
/skills

You should see the qwen-dap-mcp server and the bundled native-runtime-debug skill.

Any stdio MCP client

npx -y @slp-dev1/qwen-dap-mcp

Typical configuration:

{
  "mcpServers": {
    "qwen-dap-mcp": {
      "command": "npx",
      "args": ["-y", "@slp-dev1/qwen-dap-mcp"]
    }
  }
}

CLI discovery is available without starting the stdio server:

qwen-dap-mcp --help
qwen-dap-mcp --version

30-second example

You: Debug why app.exe crashes with --repro

Coding agent
  ↓
qwen-dap-mcp starts a DAP debugger
  ↓
captures the native failure + project-controlled frame
  ↓
correlates stack + registers + locals + disassembly
  ↓
backtracks runtime evidence toward the likely producer
  ↓
agent applies a minimal source fix
  ↓
builds and repeats the original reproduction
  ↓
verifies whether the original crash fingerprint is gone

The MCP server supplies debugger evidence and bounded workflow state. Source editing, builds, tests, and source-control operations stay with the coding agent's normal authorized tools.

What it does

Default agent tool surface

The default toolset intentionally exposes 14 high-signal tools:

Need raw stacks, scopes, variables, memory, modules, breakpoints, evaluation, stepping, or adapter-specific controls? See the opt-in full toolset in docs/toolsets.md.

Debugger support

Adapter discovery, prerequisites, and platform-specific setup are documented in docs/README.md.

More than raw DAP

Raw DAP is intentionally low level. qwen-dap-mcp keeps raw debugger access available in the full toolset, but its default surface focuses on workflows an agent can reason about directly.

Safety by design

A debugger can execute and mutate target state, so the bridge treats that power explicitly.

• No arbitrary shell tool is exposed by the MCP server.
• No source-writing primitive is exposed by the MCP server.
• No general memory-write primitive is part of the default agent surface.
• Remote endpoints are validated and non-loopback access requires explicit allowlisting.
• Autonomous workflow state is explicit rather than hidden inside a background loop.
• Optional HOL Guard 2.2+ integration can fail closed before protected adapter startup or executable/mutating DAP actions cross the debugger boundary.

Read the full policy and threat model in docs/hol-guard.md and SECURITY.md.

Repro labs and benchmark harness

The repository includes deterministic native fixtures so behavior can be tested instead of demonstrated only with screenshots:

npm run demo:build -- null-pointer
npm run demo:repro -- null-pointer

npm run demo:hang:build -- deadlock
npm run demo:hang:repro -- deadlock

benchmark/ also contains a reproducible comparison harness for source-only, dap-raw, and qwen-dap-mcp workflows. It deliberately ships without invented performance numbers; publishable results should record the exact model, settings, commit, reproduction, raw outcome, and verification status.

Documentation

Start with the documentation index.

Development

Requirements: Node.js 20+.

git clone https://github.com/SLP-DEV1/qwen-dap-mcp.git
cd qwen-dap-mcp
npm ci
npm run check

Read the full README on GitHub →