dsh-plugin-kit

Writing a function plugin for DeepSeek Harness is rarely hard in the business logic; the friction lives in the minimal correct loop — which manifest field to declare, how the patch YAML attaches, where registration and teardown happen inside apply, and how defineTool validation meets output.render projection. dsh-plugin-kit compresses all of that into a single installable package, running 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, which the installer appends to the ordered dsh.profile.bundles list; the patch file is a top-level YAML array that replaces an entire row by id rather than merging 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 runs, and both output.schema and output.render stay lossless JSON.

It suits 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 key is read — and CI needs only two commands on Node 22 and 24 with zero external credentials. The package pins to the 0.1.1-rc.2 line and locks the exact version in devDependencies to avoid latest-tag drift.