Introduction

Use Harmony when one DeepSeek Harness plugin needs to change another without maintaining a fork. Harmony loads Patches before the target runs, changes its compiled code in memory, and starts Harness with the result.

Source Patches find TypeScript AST nodes with TSQuery and rewrite their source ranges with MagicString. They run one after another, each reading the source left by the previous Patch. This lets several plugins change the same target while leaving installed files untouched.

A provider can place its Patches before or after another provider. One Patch may override that rule, and users may interleave Patches from different providers. When several changes must succeed together, a composite Patch gives them one position and one switch; if a member fails, Harmony applies none of them.

For browser plugins, Harmony also keeps provider-owned <style data-plugin> tags in Patch order. A provider owns one style group, so its last enabled Patch decides where that group appears in the CSS cascade. Harmony repeats the ordering after a Patch reload.

Harmony adds modification to the ways DeepSeek Harness plugins can work together.

Why Harmony

Ordinary DSH extension points remain the first choice when the target exposes the behavior you need. Harmony is for the gap between those APIs and maintaining a fork: changing an internal component, loader entry, or compiled behavior that the target does not expose.

Without Harmony	With Harmony
Hide or duplicate an internal UI and keep both implementations aligned	Replace the selected component or compiled call site in place
Patch node_modules, carry a fork, or reapply edits after upgrades	Transform source in memory; installed package files remain byte-for-byte unchanged
Discover a selector drift only after the UI silently breaks	Pin package version and expect; mismatches fail visibly in status
Treat the final bundle as a black box	Inspect the original, every Patch step, and the final transformed source
Remove custom edits manually	Disable or remove the Provider to restore the original behavior

Harmony does not turn compiled internals into a stable public API. It makes that dependency explicit, ordered, inspectable, and reversible.

Respect

Inspired by Harmony, the project of the same name created by Andreas Pardeike and other contributors for C#.

AI agents: use the repository skill

Load use-dsh-harmony for installation, Patch selection and authoring, runtime operations, and troubleshooting.

Install

Requires Node.js ^22.22.3 or >=24.11.1 and @deepseek-ai/dsh@0.1.0-rc.7.

npm install -g @deepseek-ai/dsh@0.1.0-rc.7
npm install -g dsh-harmony
dsh web

Open Settings → Harmony after starting the WebUI. For profiles, Desktop integration, updates, and removal, see the installation guide.

Patch model

Harmony runs every Patch from one global patchOrder. Provider-level before and after rules set the usual order. A Patch that declares either rule uses its own rules instead. In Settings → Harmony, users can move a whole provider or place one Patch between Patches from another provider. Harmony checks that the saved list contains every registered Patch exactly once.

A composite Patch groups several Patches under one order position and switch. Members keep their declared order and apply only when every member succeeds. A failed standalone Patch is reported and skipped; later Patches and the Host continue to run.

React-aware patches

Install dsh-harmony-react in a Patch provider when the target is compiled React:

npm install dsh-harmony-react

Use element() to change selected compiled jsx / jsxs calls. Use component() to change the shared component definition. Harmony applies both in the same Patch order as every other Source Patch.

API	Scope
element()	One or more selected call sites: replace, wrap, insert, transform props, or remove
component()	Every call through an initialized variable or named function declaration: decorate or replace

To let later Component Patches modify the same definition, Harmony rewrites a function declaration as an initialized const. The new binding is not hoisted. If the file reads the component before its declaration, use a core Source Patch instead. React integration covers selectors, Inspect traces, and Studio.

Documentation

Topic	Guide
Runtime architecture	What is Harmony?
Installation and profiles	Installation
Writing source, semantic, loader, and composite Patches	Patch authoring
Provider/Patch order, status, inspection, and reload	Operations
React-aware patches with dsh-harmony-react	React integration
Studio previews	Studio integration
Commands, limitations, and failures	CLI · Limitations · Troubleshooting

Development

All maintained implementation code uses TypeScript. Build artifacts are generated for packaging and are not tracked by Git.

Documentation sources and local preview tooling live on the docs branch.

npm test

License

MIT