ensure-pipelines-host

> **Plugin check**: Run `node "${CLAUDE_PLUGIN_ROOT}/scripts/check-version.js"` — if it outputs a message, show it to the user before proceeding.

<!-- alm-lint-ignore: SKILL-must-read-manifest — this skill manages the Pipelines host environment (deploymentenvironments / deploymentpipelines tables on the host), not the source-env solution. The site's .solution-manifest.json is irrelevant to host lifecycle: a host can be provisioned before any solution exists, and a single host is shared across many solutions. ALM-aware-by-default does not apply. -->

# ensure-pipelines-host

> **Scope:** When no host is bound to the source env, this skill detects any existing host (Custom or PE) for reuse, or — in `NoHost` state — offers three provisioning paths: a new **Platform Host** (recommended; idempotent, ~3–5 min); a new **Custom Host** (admin-only, ~5–10 min); or PPAC manual provisioning (fallback). Implementation details — endpoint names, template names, BAP audience — live in Phase 4.0 / 4.A / 4.C below; user-facing prose stays focused on outcomes.

Power Platform Pipelines need a **host environment** — a Dataverse environment with the *Power Platform Pipelines* managed solution installed, where pipelines, stages, run history, and artifacts live. The existing `setup-pipeline` and `deploy-pipeline` skills assume a host is already configured. This skill closes that gap.

## What we know (sources of truth)

This plan is grounded in three primary sources, in priority order:

1. **`useGetOrCreatePlatformEnvironment.v4.ts`** (Microsoft-internal client source — `power-platform-ux/packages/powerapps-appdeployment-ux/src/hooks/v4/`). Defines the exact HTTP contract for Platform Environment provisioning: endpoint, body, headers, polling.
2. **`ProjectHostProvider.tsx`** (same repo, `src/components/ProjectHostProvider/`). Defines the exact resolution order the Power Apps UI uses to determine which environment is the project host for a source environment. We mirror that order so this skill agrees with the UI.
3. **eng.ms `createcustompipelineshost`** (Microsoft-internal). Documents the Custom Host fast-path: a `D365_ProjectHost` org template that ships the Pipelines app pre-installed, callable through the standard environment-creation API.

Public Microsoft Learn (`learn.microsoft.com/power-platform/alm/{platform-host-pipelines, custom-host-pipelines, set-a-default-pipelines-host}`) is the user-facing description of the same flows; we cite it for behaviors users will recognize. HARs in `PipelinesDeployScenario.har` and `Pipelines.har` confirm the read-side calls.

## Three host shapes the tenant can be in

| Shape | How it got there | Where it lives | Org template |
|---|---|---|---|
| **Platform Host (PE)** | Auto-provisioned by `getOrCreate` BAP call (or as a side-effect of first navigation to the Pipelines page in `make.powerapps.com`). Hidden from the env picker. One per tenant. | Microsoft-managed Dataverse env in tenant's home geo | `D365_1stPartyAdminApps` |
| **Custom Host** | Created by an admin via PPAC `Deployments → New custom host`, or via the standard env-create API with the `D365_ProjectHost` template, or by installing the Power Platform Pipelines app on an existing Dataverse env. | A regular Dataverse env in the tenant | `D365_ProjectHost` (or app-installed-onto-existing-env) |
| **No host bound to source env** | Tenant has not used Pipelines from this env. | — | — |

The current `discover-pipelines-host.js` only checks the tenant-level `DefaultCustomPipelinesHostEnvForTenant` setting. That's one signal of many. This skill implements the full resolution order.

## Resolution order (mirrors `ProjectHostProvider.tsx`)

This is the load-bearing decision tree. It is what the Power Apps UI does. We replicate it so the skill agrees with the UI.

```
┌─────────────────────────────────────────────────────────────────────┐
│ 1. GetOrgDbOrgSetting('ProjectHostEnvironmentId') on source env     │
└──────────────────────────┬──────────────────────────────────────────┘
                           │
            ┌──────────────┴───────────────┐
            │ value present                │ value empty
            ▼                              ▼
┌───────────────────────┐         ┌────────────────────────────┐
│ 2. Resolve env via    │         │ 5a. Tenant-wide search:    │
│    BAP GET            │         │   list envs + per-env      │
│    /environments/{id} │         │   /deploymentpipelines     │
└───────┬───────────────┘         │   probe.                   │
        │                         │                            │
   environmentSku?                │   - 1 Custom Host found →  │
        │                         │     AvailableUnboundCustom │
   ┌────┴────────────┐            │     (3.C-pre)              │
   │ Platform        │            │   - >1 Custom Hosts →      │
   │                 │            │     MultipleUnboundCustom  │
   │                 │            │     (3.C-pre')             │
   │                 │            │   - PE only →              │
   │                 │            │     PlatformHostExists-    │
   │                 │            │     Unbound (3.C-pre'')    │
   │                 │            │   - none → NoHost (3.C)    │
   │                 │            │                            │
   │                 │            │ 5b. Decision tree paths    │
   │                 │            │   for create-new (3.C):    │
   │                 │            │   - Platform getOrCreate   │
   │                 │            │     (fast-path, no admin)  │
   │                 │            │   - Custom D365_ProjectHost│
   │                 │            │     (fast-path, admin)     │
   │                 │            │   - Manual app install     │
   │                 │            │   - Manual PPAC create     │
   │                 │            └────────────────────────────┘
   ▼                 │
┌──────────────┐     │
│ 3. Check     │     │ environmentSku ≠ Platform (Custom Ho