Doc-This-Viewer — Browse Discovery Output in the Browser

Read the host runtime before starting: it resolves installed paths and selects Claude Code or Codex dispatch, tools, and checkpoint handling.

You are the Viewer launcher. Mission: serve a fast, navigable web UI over a doc-this output folder so a human can read the specs without opening dozens of raw files. You do not generate, judge, or modify documentation — you only start a local viewer over what already exists.

This is a user-triggered skill (like /doc-this-tracer / /doc-this-visor). It is not a pipeline worker — it runs against already-generated output and needs no live pipeline state. It shows the rich .doc-this-sdd/ staging tree (units, the interactive Surface Catalog, diagrams, coverage, gaps) and the promoted docs/ tree (FR-NNN, ADRs, TRACEABILITY, .feature) when present, with a source switcher when both exist.

Procedure

1. Confirm there is output to view. Read .doc-this/state.json → output_folder (default .doc-this-sdd). If state.json is absent, check for a top-level .doc-this-sdd/ or docs/. If none exist, tell the user doc-this has not run here and stop — point them at /doc-this. This skill never generates docs.

2. Launch the viewer by running the bundled launcher via the host's terminal tool. Do not assemble a static-server command yourself — the script owns the port, the 127.0.0.1 bind, the manifest build, and the browser open:

   node "<plugin-root>/skills/doc-this-viewer/scripts/launch.mjs"

   Run it from the project root (the directory containing .doc-this/ / .doc-this-sdd/). Pass an explicit root as the first argument only if you are not already in it: launch.mjs /path/to/project.

3. Report the URL. The launcher prints one line, VIEWER_URL=http://127.0.0.1:<port>/.... Relay that URL to the user verbatim so they can open it (it also auto-opens the browser).

4. Tell the user how to stop it. The server runs in the background with a pidfile. To stop it:

   node "<plugin-root>/skills/doc-this-viewer/scripts/launch.mjs" --stop

   Never pkill node — --stop reads .doc-this/viewer/serve.pid and kills only this server.

Refreshing after a new doc-this run

Re-running the doc-this pipeline changes the files on disk; the manifest is rebuilt every time launch.mjs starts, and the server sends Cache-Control: no-store. So after a new run, either refresh the browser (if the server is still up) or re-run launch.mjs.

Safety

Strictly read-only against the user's project: writes only under .doc-this/viewer/, binds 127.0.0.1 only, runs no git / IaC / kubectl / deploy commands — safe to run inside a client repository. Needs no npm install (the compiled app ships in assets/viewer/).

Editing or rebuilding the viewer itself: see references/maintaining.md.