Artifact write procedures for the prereq phase exit. Read at Step 4 of the [readiness gate](readiness-gate.md).

## Write Artifacts

> ⛔ **Write all 3 artifacts before exiting prereq.** Downstream phases read these.
> ⛔ **Use `create` tool for ALL session files — NEVER `powershell`.** Terminal is OK ONLY for read-only ops: UUID generation, git info, file existence checks.
> ⛔ **Path scoping:** ALL `create` calls target `.copilot-azure/sessions/{uuid}/`. After writing, read back to confirm correct path.

1. **`prereq-output.json`** — ⛔ Read [`prereq-schemas.ts`](prereq-schemas.ts) for `PrereqOutput` interface.

   > ⛔ **Per-component verdicts MUST persist.** Every entry in `components[]` MUST include a `verdicts` object: `{ "build", "completeness", "deployability" }` with values `PASS`/`WARN`/`FAIL` (`build` may be `SKIPPED` when build validation was skipped; `completeness`/`deployability` are never `SKIPPED`). Downstream readiness scoring and the prepare phase read these — never omit them.
   >
   > ⛔ **Warnings MUST persist.** Every ⚠️ WARN → `warnings[]`: `{ "id": "W-{ID}", "component", "axis", "summary", "detail", "fix", "fixPhase" }`. Both `fix` and `fixPhase` are required — validate before writing.
   >
   > ⛔ **Health endpoint:** Write detected path to `healthEndpoint` (e.g., `"/api/v1/health/"`). If none → `null` + `W-HEALTH` warning with `fixPhase: "scaffold"`.
   >
   > ⛔ **Entry point:** Write to `entryPoint` (e.g., `"index.js"`). `null` for .NET/Go/Java (Oryx handles startup).
   >
   > ⛔ **`postDeployRecommendations[]`:** For each ⚠️ WARN, write per `PostDeployRecommendation` schema from [`session-schemas.ts`](session-schemas.ts): `{ "title", "reason", "effort": "low|medium|high", "services": [] }`.

2. **`context.json`** — ⛔ Use `edit` (not `create` — Step 1 already created it). Populate `components[]`, `repo`, `detectedInfra[]`, `detectedServices[]`, `app.name` (from primary component's project manifest or workspace root dir name). Append `"prereq"` to `completedPhases` NOW (before presenting), set `currentPhase: null`, update `lastModifiedUtc`.

3. **`readiness-report.md`** — Summary table (Build/Completeness/Deployability verdicts), detected stack, all warnings with actionable detail. Clean markdown, no rigid template.

> ⛔ **Phase exit gate:** All 3 artifacts must exist. If any missing, write NOW.