dsh-plugin-kit

Building a function plugin for DeepSeek Harness rarely trips you up on business logic; it trips you up on the minimal correct loop — which manifest field to declare, how the patch YAML attaches to the profile, where registration and teardown happen inside apply, and how defineTool validation meets the output.render projection. dsh-plugin-kit compresses all of that into a single installable package that runs the full chain through one tool called kit_ping, so you never have to assemble the scaffold from scratch.

It plays double duty as a profile bundle and the plugin that bundle mounts. The manifest declares dsh.bundle.patch, and the installer appends the package to the ordered dsh.profile.bundles list; the accompanying patch file is a top-level YAML array whose entries replace an entire row by id rather than merging individual keys. On the plugin side, registration happens inside apply, a hard dependency on tools is declared via inject, and the disposer returned by register hands lifecycle ownership back to the Cordis fiber — stopping, updating, or reloading the plugin automatically unregisters the tool. The parameter schema is an implicit open object root: missing fields or wrong types raise ToolArgsError before the body ever runs, and both output.schema and output.render stay lossless JSON with explicit additionalProperties on every nested object.

It fits developers who are new to the Harness plugin surface and want to confirm patch-layer composition order and Cordis lifecycle semantics, as well as teams looking for the smallest forkable scaffold to swap kit_ping for a real tool. The test suite is offline by construction — a stub context records registrations, no socket opens, no API key is read — and CI runs two plain commands on Node 22 and 24 with zero external credentials. The package pins the 0.1.1-rc.2 line and locks the exact version in devDependencies to sidestep npm latest-tag drift, making it safe to install in any environment without side effects.