[!NOTE] 📦 This plugin lives in the dsh-plugins monorepo — file issues & pull requests there. npm: @hy-sde-org/dsh-dap · @hy-sde-org/dsh-tool-debug

dsh-tool-debug — a real DAP debugger for DeepSeek Harness

Two standalone packages, installable as one plugin for the DeepSeek Harness CLI:

package	role	installed by users?
@hy-sde-org/dsh-dap	standalone Debug Adapter Protocol seam: DAP client + session manager (launch/attach, breakpoints, stepping, frames/scopes/variables, evaluate, memory, modules, output, terminate)	no — transitive
@hy-sde-org/dsh-tool-debug	the plugin: the model-facing debug tool (28 operations) rendered as launch/breakpoint/step/stack/evaluate results	yes

The debug tool is a parity port of oh-my-pi's coding-agent debug tool onto the harness tool contract (ctx.tools, ctx.dap, ctx.systemPrompt). The DAP seam spawns real debugger adapters (debugpy, lldb-dap, gdb, dlv, js-debug, ...) as local binaries over stdio or a reserved TCP port, resolves adapter availability into structured "unavailable" errors that name the install command, and returns a session snapshot from every operation so the agent always sees consistent debugger state. Everything works on stock DeepSeek Harness releases with zero upstream changes.

Why

Coding-agent debugging is mostly harness: a real stepping/breakpoints debugger — versus "insert print statements and rerun" — is the difference between interrogating a fault and instrumenting around it. This plugin ports a proven DAP debugger into the model's tool surface and ships it as an installable plugin.

Prerequisites

• Node.js 22.19 or newer (the packages' engines floor) with npm and pnpm on PATH;
• a DeepSeek Harness installation including the standard dsh CLI — the peer baseline is @deepseek-ai/cordis ~4.0.4 and @deepseek-ai/dsh-tools/dsh-system-prompt/ dsh-timeout/dsh-invariants ^0.2.0-rc.2;
• at least one debugger adapter for the languages you want to debug, discovered at runtime via PATH (debugpy also via DSH_DEBUGPY_PYTHON): debugpy (pip install debugpy) for Python, lldb-dap or gdb for C/C++/Rust, dlv (go install github.com/go-delve/delve/cmd/dlv@latest) for Go, vscode-js-debug for JavaScript/TypeScript. An unavailable adapter is a structured error naming the install command, not a crash.

Install

pnpm install --global @deepseek-ai/dsh

Route A — published npm package (recommended)

Both packages are published on the npm registry under the hy-sde-org organization (@hy-sde-org/dsh-dap and @hy-sde-org/dsh-tool-debug, version 0.2.0-rc.2). Install the plugin straight from npm — the registry resolves the dap library dependency and the DeepSeek Harness peer packages automatically:

# one command; @hy-sde-org/dsh-dap comes in as a transitive dependency
dsh plugin --profile web add @hy-sde-org/dsh-tool-debug

Installing the bundle alone never breaks boot and never claims any name on the host plane — the harness has no stock debug tool to shadow. The tool becomes available when you mount the provided agent preset row.

Route B — from source (validate this checkout or hack on the plugin)

git clone git@github.com:hy-sde/dsh-plugins.git
cd dsh-plugins
pnpm install

DEBUG_TGZ="$(cd dsh-tool-debug/packages/tool-debug && pnpm pack --pack-destination /tmp | tail -n 1)"
dsh plugin --profile web add "$DEBUG_TGZ"
cd ..

prepack runs the package's clean + build, so the tarball always carries current dist/ for the tool. The @hy-sde-org/dsh-dap seam is a regular dependency resolved from npm — it is not inside the tool tarball; pack and add packages/dap too when validating local dap changes.

Verify

dsh web --dump-config

The bundle's patch is a documented no-op — it inserts no rows and disables nothing — so installation changes nothing in the composed tree, and nothing debug-named appears on the host plane; boot is unaffected. The tool exists only for agents whose preset mounts the dap + tool-debug rows (see Giving agents the debug tool below): with the preset selected, ask the agent to run debug with action: "sessions" — an empty session list, or a structured "no debugger adapter available" error naming the install command, confirms the seam resolves.

Run

Give agents the preset row (see Giving agents the debug tool below), then ask the agent to debug. One grounded round trip against a Python program with debugpy:

debug { "action": "launch", "program": "server.py", "adapter": "debugpy" }
debug { "action": "set_breakpoint", "file": "server.py", "line": 42 }
debug { "action": "continue" }
debug { "action": "stack_trace" }
debug { "action": "evaluate", "expression": "len(rows)" }
debug { "action": "terminate" }

One active session at a time — terminate before launching another. Breakpoints must be set before continuing after a stop; an unavailable adapter is a structured error that names the install command, not a crash.

Uninstall

dsh plugin --profile web remove @hy-sde-org/dsh-tool-debug

Giving agents the debug tool

packages/tool-debug/examples/agent-preset/ contains a ready-to-copy user preset. Copy agent.cordis.yml and preset.yml to ~/.dsh/.agent-presets/<id>/, select the preset in the Web UI preset picker (or dsh agent CLI), and agents in that preset get the debug tool. The preset mounts the dap service in its own isolated realm so each agent owns its adapter processes and breakpoint state, with tool-debug beside it:

- id: debug
  name: cordis:group
  group: true
  isolate:
    dap: true
  config:
    - id: dap
      name: '@hy-sde-org/dsh-dap'
    - id: tool-debug
      name: '@hy-sde-org/dsh-tool-debug'

What the bundle does

• Inserts no rows and disables nothing. The official harness has no debug tool, so there is no collision to manage — the bundle's patch is a documented no-op that keeps the package installable as a normal plugin.
• Mounts at the agent plane. The preset row above is the only surface the model sees; it is scoped per session.
• Adapters are local binaries. debugpy (pip install debugpy), gdb, lldb-dap, dlv, and vscode-js-debugger are discovered at runtime via the PATH/DSH_DEBUGPY_PYTHON environment; unavailability is a structured error, not a crash.

Tool operations

launch · attach · set_breakpoint · remove_breakpoint · set_function_breakpoint · remove_function_breakpoint · set_instruction_breakpoint · remove_instruction_breakpoint · data_breakpoint_info · set_data_breakpoint · remove_data_breakpoint · disassemble · read_memory · write_memory · modules · loaded_sources · custom_request · continue · pause · step_in · step_out · step_over · threads · stack_trace · scopes · variables · evaluate · get_output · terminate · sessions · capabilities

Development

pnpm install
pnpm -r check   # typecheck both packages
pnpm -r test    # framing + session specs + the opt-in live debugpy round trip
pnpm -r build   # tsc -> dist for both
bash scripts/release-public.sh --check   # clean tree + checks + tests + pack

For the live debugger round trip, point the suite at a Python with debugpy installed:

DSH_DEBUGPY_PYTHON=/path/to/python pnpm --filter @hy-sde-org/dsh-dap test

Layout

packages/dap/          @hy-sde-org/dsh-dap        (the DAP seam/engine)
  src/client.ts        DAP client + Content-Length framing
  src/session.ts       DapSessionManager
  src/config.ts        adapter resolution + launch defaults
  src/defaults.ts      omp default adapter configuration
  src/env.ts           python/debugpy probing
  tests/               framing + session specs + live debugpy round trip
packages/tool-debug/   @hy-sde-org/dsh-tool-debug (the `debug` tool plugin)
  src/index.ts         tool plugin entry (schema, config, dispatch)
  src/render.ts        result rendering the model reads
  src/session.ts       per-call dispatch over ctx.dap
  cordis.patch.yml     zero-effect install patch
  examples/agent-preset/ ready-to-copy user preset

See THIRD-PARTY-NOTICES.md for provenance, CONTRIBUTING.md for the contribution and release flow.

License and attribution

This package is licensed MIT — the same license as its upstream oh-my-pi (https://github.com/can1357/oh-my-pi). The DAP seam and the debug tool are ported from oh-my-pi's coding-agent debug tooling (MIT License, © Mario Zechner 2025, © Can Bölük 2025-2026); the upstream copyright holders are recorded in LICENSE next to this package's own notice, and the upstream notice text is reproduced in full in THIRD-PARTY-NOTICES.md.