dsh-format-after-edit

dsh-format-after-edit

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Agents don't run your formatter. They write code with their own idea of quotes, wrapping and trailing commas, and you find out at review time, or when CI's format check fails and the agent spends a turn "fixing" whitespace. Telling it to run Prettier after every edit works until it forgets.

This DeepSeek Harness plugin runs the project's own formatter on each file right after the agent writes or edits it. When the formatter changes the file, the model is told, so its next edit doesn't target text that has moved:

The file src/api/client.ts has been updated successfully.

[dsh-format-after-edit] prettier reformatted src/api/client.ts (4 lines changed). Re-read the file
before editing it again, since text you saw earlier may have moved or changed.

When the formatter fails, which usually means the edit broke the syntax, the model sees why:

[dsh-format-after-edit] ruff could not format app/models.py. Your edit was saved, but this often
means it has a syntax error:
error: Failed to parse app/models.py:14:5: Expected an indented block after function definition

Install

dsh plugin --profile web add dsh-format-after-edit

That's the web profile, the browser UI you start with dsh web. If you run DSH another way, use headless (scripts and CI) or acp (editor integrations) instead. Each profile keeps its own plugin list, so add it to every profile you use. It's on as soon as it's installed. Remove it with dsh plugin --profile web remove dsh-format-after-edit.

It's also part of dsh-guard-pack, which installs nine guards at once.

Which formatter runs

The one your project is set up for. A formatter runs only when the project has its config and the tool is installed locally or on your PATH. Nothing is ever downloaded, so a repo without a formatter is left alone.

Files	Formatter	When
JS, TS, JSON, CSS, Markdown, YAML, HTML, Vue, Svelte...	Prettier	.prettierrc*, prettier.config.* or a "prettier" key in package.json, and prettier in node_modules
JS, TS, JSON, CSS, GraphQL...	Biome	biome.json(c), and @biomejs/biome in node_modules
Anything dprint has plugins for	dprint	dprint.json or .dprint.json(c), and dprint in node_modules
Python	Ruff	ruff.toml, .ruff.toml or [tool.ruff] in pyproject.toml, and ruff in the venv or on PATH
Python	Black	[tool.black] in pyproject.toml, and black in the venv or on PATH
Go	gofmt	a go.mod, and gofmt on PATH
Rust	rustfmt	a Cargo.toml (its edition is used), and rustfmt on PATH
C, C++, Objective-C, protobuf	clang-format	a .clang-format, and clang-format on PATH

The closest config wins, so a monorepo package with its own biome.json uses Biome even if the root has a .prettierrc. Each formatter's own ignore file (.prettierignore, Biome's files.ignore...) is respected. Lockfiles, node_modules, dist, build, vendor and minified files are never touched.

Your own formatter

For anything else, add a command. {file} becomes the edited file's path, quoted. Custom entries are checked before the built-in ones.

- id: format-after-edit
  config:
    custom:
      - files: ['*.php']
        command: vendor/bin/pint {file}
      - files: ['*.java']
        command: google-java-format --replace {file}
      - files: ['**/*.tf']
        command: terraform fmt {file}

Settings

The easy way: open Plugins in DSH's sidebar, click dsh-format-after-edit, change what you want and press Save. Custom commands go in cordis.patch.yml.

Add a row like this to ~/.dsh/profiles/ /cordis.patch.yml, or to ~/.dsh/cordis.patch.yml for every profile. Keys you leave out keep their defaults.

- id: format-after-edit
  config:
    formatters: [prettier, biome, dprint, ruff, black, gofmt, rustfmt, clang-format]
    custom: []
    ignore: ['**/node_modules/**', '**/dist/**', '*.lock']   # replaces the default list
    tools: [write, edit, str_replace_editor]
    timeoutMs: 20000
    reportChanges: true   # tell the model when the file changed
    reportErrors: true    # tell the model when the formatter failed

Development

npm install        # from the repository root
npm test -w packages/dsh-format-after-edit
npm run test:e2e   # real dsh runs against a scripted local model, no API key needed

MIT licensed. Written by acus9345. Bug reports and ideas are welcome in the issues.