MOSTLY HISTORICAL — but one fixture below is still live.

fixtures/pid_topology_mock.json is NOT dead and must not be deleted. workflows/document_pipeline.py:211 falls back to it when the NIM vision model cannot parse a P&ID, and sets topology_source: "demo_fixture" — which the UI is required to disclose. That is the mock-by-design path, and removing the file breaks P&ID fallback. fixtures/test.wav is manual test audio for the voice-note flow (referenced from BE.md / FE.md), not used by code.

Everything below about the frontend fixture system is historical:

lib/{fixtures,assets,governance,documents,events,compliance}.ts and the DemoChip component were deleted on 2026-08-15, and DataSource narrowed to a single member ("live") so a fallback cannot return without a type error. Fetchers now throw; the UI shows live data, a skeleton, or error+retry.

Three of these paths were not dead when removed — getEvents, governance/moc and governance/model-gate rendered fabricated data on successful requests. Kept here as a record of what the system used to do and why it was removed.

Kairos — Fixtures Reference

For AI coding agents: This doc covers two very different kinds of fixture.

⚠️ The frontend is now LIVE-ONLY. The web app never displays fabricated data. Every page shows real backend data, a loading skeleton while fetching, or an error + retry if the backend is unreachable — never a fixture. useFetch treats a fixture fallback as an error, server pages throw on it, and the few custom-client pages show an inline retry. See §3.

Two paths used to bypass that policy and no longer do. synthesize() and getRcaPack() in lib/api.ts do not return a Fetched<> envelope, so useFetch's guard never applied to them — on any error they returned a hardcoded answer with invented document IDs, rendered identically to a real cited answer. Both now throw; the copilot shows a per-turn AnswerError with retry and the RCA page its existing failed state. The copilot fixtures (SEAL, PRESSURE_REFUSAL, ISOLATION, GENERIC, answerFor) are deleted from lib/copilot.ts — that file now holds types and suggestions only. rcaFor in lib/rca.ts survives but is marked TEST-ONLY (rca/page.test.tsx uses it to mock getRcaPack) and must never be imported by api.ts.

Backend fixtures below are mock-by-design — they stand in for external plant systems Kairos does not own (EAM golden record, OT historian, P&ID vision model) and are the intended MVP state, not a gap. This doc maps each to the endpoint it backs, its data contract, and when it fires.

Table of Contents

1. Fixture Fallback Pattern
2. Fixture Files
3. Frontend Live-Only Policy

1. Fixture Fallback Pattern

Backend (Go connector): Environment variable absent → fixture file loaded from disk.

// EAM sync — fires when EAM_ODS_ENDPOINT is not set
if os.Getenv("EAM_ODS_ENDPOINT") == "" {
    // reads EAM_FIXTURE_PATH (default: /app/fixtures/sample_assets.json)
}

Backend (Python API): Live service unreachable → fixture JSON returned inline.

Frontend: LIVE-ONLY (see §3). Read fetchers return { data, source }, but DataSource is now a single member — "live" (api.ts:250). There is no "demo" value to return, so a fixture fallback cannot be reintroduced without a type error. Fetchers throw on failure. Read timeout 4 s (getJson), writes 8 s (postJson), synthesize() 90 s.

2. Fixture Files

fixtures/pid_topology_mock.json

Backed endpoint: GET /documents/{id}/topology
Fires when: Ingest-time fallback for pid_drawing documents when the Layer 3 vision model (PIDService, Path B) is unreachable or returns unparseable output. On the real path the topology comes from the model; the fallback is flagged topology_source: "demo_fixture" so it never masquerades as a real extraction.
Mount path: fixtures/ is mounted into kairos-backend-api and kairos-celery-worker at /app/fixtures/.

Schema:

Demo content: 5 equipment nodes (pump P-101, tank TK-201, heat exchanger HX-301, flow transmitter FT-3047, pressure gauge PG-18), 3 isolation valves, 2 instrumentation loops, 1 isolation boundary with double-block-bleed requirement.

backend/connectors/fixtures/sample_assets.json

Backed endpoint: POST /eam/sync (Go connector)
Fires when: EAM_ODS_ENDPOINT env var is not set (default in local dev).
Mount path: Mounted into kairos-backend-go at /app/fixtures/sample_assets.json. Controlled by EAM_FIXTURE_PATH env var.

Schema (array of asset objects, matches POST /assets request body):

Demo content: 5 assets — P-101 (pump, safety_critical), V-201 (vessel, critical), HX-301 (heat exchanger, critical), C-401 (compressor, safety_critical), T-501 (tank, non_critical). All on SITE_001.

fixtures/test.wav

Backed endpoint: POST /elicitation/{work_order_id}/voice (voice note upload — the frontend field route /field/voice posts here)
Fires when: Used in integration tests and manual dev testing only — not a runtime fallback.
Purpose: A short WAV file for testing the Groq Whisper transcription pipeline without needing a real recording. Feed it via the voice upload endpoint to exercise the full transcribe_voice_note Celery task.

3. Frontend Live-Only Policy

The web app never shows fabricated data, and this is now enforced by the type system rather than by convention: DataSource = "live" is a single-member union, so a fetcher cannot return a fixture source at all. Fetchers throw on failure.

• Client pages (useFetch) — a rejected fetcher becomes the page's error+retry state.
• Server pages (assets, asset detail, briefs, documents, doc detail, off-boarding) — throw on demo → the shared (app)/error.tsx boundary + (app)/loading.tsx skeleton. ((app)/layout.tsx is dynamic = "force-dynamic" so these render per request, never prerendered at build.)
• Custom-client pages (governance hub, MoC detail, plant-state, projects, off-boarding session, field elicitation) — show an inline "unavailable — retry" instead of the fixture.
• /overview/cross-site has no backend (single-site MVP) — it shows an honest "No cross-site data in this deployment" state, not fabricated alerts.
• A few fetchers additionally treat empty live data as a valid state (e.g. getComplianceGaps no longer substitutes a fixture on empty).

So the net user experience everywhere is: real data · loading skeleton · error+retry — never a demo chip.

The cleanup is done, not optional. <DemoChip> and its 10 render sites were deleted on 2026-08-15, along with lib/{fixtures,assets,compliance,documents,governance}.ts. Verified 2026-08-17: none of those files exist and DemoChip appears nowhere in frontend/src.

Two files in that original list survive deliberately, and are not fixture modules: lib/copilot.ts (live types + the real SUGGESTIONS constants + metaAnswer()) and lib/rca.ts (live types + RCA_PRESETS, plus rcaFor which is TEST-ONLY and must never be imported by api.ts).