24. Developing the plugin

One package, plain npm, no monorepo:

npm ci && npm run build && npm test          # 464 unit + integration (zero skips when services are up)
npm run coverage:ci                          # the ≥85% gate, same numbers CI enforces
npm run test:e2e:replay                      # 7 browser acceptance segments, off model TAPES
bash scripts/bootstrap-dev-profile.sh --home .dshdev-local   # isolated dev harness home

The tape system (why CI has no LLM)

E2E browser tests would normally need a live model, a GPU, and minutes per spec. Instead, recorded model exchanges are committed under tests/fixtures/model-tape/ and replayed by a proxy; every request must match a recorded exchange after normalization on both sides (volatile values — ports, paths, token counts — are masked out), or the run fails loudly with a miss journal + diff dump (candidates sorted by shared prefix). Usage numbers ride the tape, so token-meter thresholds fire at identical steps — threshold behavior under test with zero model calls. E2E_MODEL=record distills fresh tapes from the local model — once per scenario, whole projects at a time (specs share a boot); re-record when product prompts change — doc edits are free with one measured exception: near-threshold scenarios (heavy, fanout) digest injected docs into model-visible checkpoints.

The discipline, condensed

• the point of a test is to test, not skip — a test that skips for a missing dep is a bug report;
• measure before you attribute — three “bug” reports this year were each a different thing (a unit mismatch, a capacity fact, and a real defect) — the audits that decode provider units from meter units are in the repo history;
• a tape records the context it was distilled in — one journey per boot, never two GPU suites at once;
• loud beats lossy — refusals carry numbers; degradations name their step.

The contributor-facing full loop: docs/development.md and AGENTS.md in the repo (the site you’re reading is for users; those are for the agents and humans working on it). Next: 25. Internals map.