DeepSeekSoftwareShipping codeAI score · 80/100AI-assisted edit · no obvious prompt-injection riskGitHub

Install nix-dev-shell plugin for DeepSeek Harness

Input: code repo with flake.nix → Process: install plugin and restart DSH → Output: bash commands automatically run inside Nix devShell

ExperiencedStepsWorkflowTip
Who
Developers using DeepSeek Harness with Nix flake-based dev environments
You get
Harness bash commands automatically enter the matching Nix devShell without manual nix develop
You need
DeepSeek

Constraints

Prerequisites: DeepSeek Harness and Nix installed; workspace contains a valid flake.nix. Plugin installation requires restarting the DSH process. Default env mode has no per-command overhead; wrap mode has full semantic fidelity but adds ~0.3–1s per command. NIX_CACHE_HOME is auto-injected inside sandboxed workspaces to prevent nix failures from read-only ~/.cache.

What they did

Author running-grass wrote and published dsh-nix-dev-shell, a Host plugin for DeepSeek Harness. The plugin decorates the ctx.shell instance's execute method to automatically locate flake.nix in the working directory or its ancestors, then injects the corresponding devShell environment into spawned processes.

How it went

Author reports: default env mode captures environment once and reuses it with no per-command nix startup overhead; wrap mode matches manual nix develop semantics but adds ~0.3–1s per command. Cold cache (fresh temp directory) yields ~540ms for nix develop --command true; hot cache (persistent workspace directory) yields ~125ms. A 251-step, 9.5-hour session produced only 2 system/message entries. (author_report, not tested by this site)

Worth knowing

Security boundary: ancestor lookup means any flake.nix in $HOME or parent directories affects all bash commands in its subtree; shellHook runs on first command, so only enable in trusted repositories. Capture helper inherits the caller's sandbox policy without extra privileges. Known limitations: only covers ctx.shell (bash tool, subagents, hooks, background jobs); PTY terminal subsystem and tmux sessions are not covered. env mode does not pass functions, aliases, or set -x state; incompatible with plugins that replace the executor. NIX_CACHE_HOME is auto-injected for workspace-write sandboxes to prevent nix failures from read-only ~/.cache, but not injected under danger-full-access. Host SHELL is preserved; plugin always explicitly calls bash.

Steps

  1. Install the nix-dev-shell plugin

    Run the install command in terminal to add the plugin to DSH's web profile.

    Execution prompt · Source text。Terminal command to install the plugin

    dsh plugin --profile web add github:running-grass/dsh-nix-dev-shell

  2. Restart the DSH process

    Host plugins are JS modules; you must restart the DSH process after install or update for new code to load.

  3. Verify Nix devShell is active

    Run commands in a directory containing flake.nix or its subdirectories to confirm environment variables and tool paths come from the Nix store; run commands in directories without flake.nix (e.g. $HOME) to confirm native environment is preserved.

    Execution prompt · Source text。Verify devShell status; expected output: impure

    echo $IN_NIX_SHELL

    Execution prompt · Source text。Verify tools resolve to /nix/store/… (should not exist on host)

    command -v ocaml dune

    Execution prompt · Source text。Verify sandbox-writable nix cache directory is injected

    echo $NIX_CACHE_HOME

Prompt you can copy

Reference prompt · Editorial suggestion。Confirm the destination, input variables and output format before use.

This block is the prompt. Ads are never placed here.

No prompt needed — just follow the steps.

Execute install command, restart DSH, then verify; no additional prompt required.

Source

安装 nix-dev-shell，让 DSH 在 nix shell 里跑命令 · running-grass · GitHub · 2026-10-31T09:07:36Z

Comments & feedback

Tried this method? Share results, problems or improvements. Comments appear after moderation. Please avoid sensitive information.

Loading…

    Related