neon-postgres-branches

---
name: neon-postgres-branches
description: >-
  Choose and create the right Neon branch type for testing and development.
  Use when users ask about Neon branching, migration testing with real data,
  isolated test environments, schema-only branch workflows for sensitive data,
  or branch creation via Neon CLI or Neon MCP. Triggers include "Neon branch",
  "test migrations safely", "branch production data", "schema-only branch",
  "reset branch" and "sensitive data testing".
---

# Neon Postgres Branching

The outcome of this skill should be a created Neon branch (or a clear, actionable next step if creation cannot proceed).
Choose the correct branch type, then execute branch creation via MCP or CLI.

- **Normal branch** for realistic migration and query testing with real data.
- **Schema-only branch (Beta)** for sensitive data workflows where structure is needed without copying rows.

## Branch Type Decision

Use this decision rule first:

1. If the user wants to test complex migrations, performance, or behavior against production-like data, choose a **normal branch**.
2. If the user needs to avoid copying sensitive data, choose a **schema-only branch**.

If the request is ambiguous, ask one clarifying question:
"Do you need realistic data for testing, or only schema structure because the data is sensitive?"

## Tool Selection: CLI or MCP

Always support both Neon CLI and Neon MCP server. Prefer the tool the user already has installed and authenticated.

MCP link: https://neon.com/docs/ai/neon-mcp-server.md
CLI link: https://neon.com/docs/reference/cli-quickstart

### Selection order

1. Check MCP first in MCP-enabled environments:
   - If Neon MCP tools are available and authenticated (for example, listing projects works), use MCP.
2. If MCP is unavailable or not authenticated, check CLI:
   - Run `neonctl --version` to confirm CLI is installed.
   - Run `neonctl projects list` to confirm auth/context.
3. If CLI is missing, direct installation via quickstart.
4. If CLI is installed but not authenticated, guide the user through `neonctl auth` (or API key auth), then continue.
5. If both MCP and CLI paths are unsuccessful, use the Neon REST API:
   - https://neon.com/docs/guides/branching-neon-api.md

### MCP branch flow

1. Choose normal vs schema-only based on data sensitivity and migration-testing goals.
2. Use branch tools (for example, `create_branch`) to create the branch.
3. Validate with read tools (for example, `describe_branch`).
4. For migration workflows, prefer branch-based migration flows before applying to main.

## Create a Normal Branch (Preferred for Real-Data Migration Testing)

Use this when the user needs realistic testing conditions.
Real production-like data can expose edge cases your seed or data migration scripts miss, which helps catch migration issues before going live.

Link: https://neon.com/docs/introduction/branching.md

### Steps

1. Use MCP if already available/authenticated; otherwise verify CLI with `neonctl --version`.
2. Ensure project context is set (`neonctl set-context --project-id <your-project-id>`) or include `--project-id` on commands.
3. Create branch:

```bash
neonctl branches create \
  --name <branch-name> \
  --parent <parent-branch-id-or-name> \
  --expires-at 2026-12-15T18:02:16Z
```

4. Optionally fetch a connection string for the new branch:

```bash
neonctl connection-string <branch-name>
```

## Create a Schema-Only Branch (Beta, Sensitive Data)

Use this when users must not copy production rows into the test branch.

Link: https://neon.com/docs/guides/branching-schema-only.md

### Steps

1. Use MCP if already available/authenticated; otherwise verify CLI with `neonctl --version`.
2. Create schema-only branch:

```bash
neonctl branches create \
  --name <schema-only-branch-name> \
  --parent <parent-branch-id-or-name> \
  --schema-only \
  --expires-at 2026-12-15T18:02:16Z
```

If multiple projects exist, include:

```bash
neonctl branches create \
  --name <schema-only-branch-name> \
  --parent <parent-branch-id-or-name> \
  --schema-only \
  --project-id <your-project-id> \
  --expires-at 2026-12-15T18:02:16Z
```

### Beta Support Guidance (Mandatory)

Schema-only branching is in Beta. If users report unexpected behavior, errors, or missing capabilities:

1. Ask them to share feedback in the Neon Console:
   - https://console.neon.tech/app/projects?modal=feedback
2. Recommend opening a support conversation in the Neon Discord:
   - https://discord.gg/92vNTzKDGp

## Reset from parent

Use this when a child branch has drifted and the user wants a clean refresh from the parent branch's latest schema and data.

Link: https://neon.com/docs/guides/reset-from-parent.md

### What it does

- Fully replaces the child branch schema and data with the parent's latest state.
- Does not merge; local changes on the child branch are lost.
- Keeps the same connection details, but active connections are briefly interrupted during reset.

### When to recommend it

- Development or staging branch is too far behind production.
- User wants to start a new feature from a clean parent-aligned state.
- Team wants to refresh staging from production for consistent testing baselines.

### Hard constraints and blockers

- Only child branches can be reset (root branches and schema-only root branches cannot be reset from parent).
- If the target branch has children, reset is blocked until those child branches are removed.
- After a parent branch is restored from snapshot, reset-from-parent may be unavailable for up to 24 hours.
- Reset-from-parent always uses the current parent state; use Instant restore for point-in-time recovery needs.

### CLI usage

```bash
neonctl branches reset <id|name> --parent --preserve-under-name <backup-branch-name>
```

If project context is not already set, include project ID:

```bash
neonctl branches reset <id|name> --parent --preserve-under-name <backup-branch-name> --project-id <project-id>
```

`--preserve-under-name` keeps the pre-reset state as a backup branch for rollback, but adds one extra branch to clean up later.

Optional context setup to avoid repeating `--project-id`:

```bash
neonctl set-context --project-id <project-id>
```

### Console and API usage

- **Console:** Open the target child branch, then select **Reset from parent** from **Actions**.
- **API:** Use the restore endpoint for the branch and set `source_branch_id` to the parent branch ID.

## Notes and Caveats

- Schema-only branches are for structure-only cloning and sensitive/compliant data controls.
- Schema-only branches are independent root branches (no parent branch and no shared history), so reset-from-parent does not apply.
- For migration testing that depends on real-world row shapes, volumes, and edge cases, prefer normal branches.
- Root branch allowances and per-branch storage limits can cap how many schema-only branches users can create.
- If a user is unsure, default recommendation is:
  - **Normal branch** for migration validation.
  - **Schema-only branch** for compliance and privacy constraints.

## Useful Workflow Patterns

If the user asks for process recommendations (not just a single command), suggest these:

- **One branch per PR:** Create branch when PR opens, delete when merged/closed, keep migration tests isolated.
- **One branch per test run:** Create branch at pipeline start, run migrations/tests, delete at end for deterministic CI.
- **One branch per developer:** Isolated dev environments with production-like shape; avoid team collisions on shared test data.
- **PII-aware branching:** If production has sensitive data, derive dev/PR branches from an anonymized branch or use schema-only branches.
- **Ephemeral lifecycle hygiene:** Set branch expiration and automate cleanup so old branches do not accumulate avoidable storage/history cost.

### Post-creation environment update prompt

After branch creation, ask whether the user wants to update local environment credentials to point at the new branch.

- Ask: "Do you want me to update your `.env` `DATABASE_URL` to this new branch connection string?"
- If yes, write the new branch connection string to the requested env file/key.
- If no, leave credentials unchanged and share the connection string for manual use.
- Never overwrite an existing env key without explicit confirmation.

## Neon Infrastructure as Code (`neon.ts`)

Beyond creating branches imperatively (CLI / MCP / API above), you can **program what configuration new branches receive** declaratively in `neon.ts` — Neon's infrastructure-as-code file (see the `neon` skill for the full reference). The `branch` property is a function of the branch being evaluated that returns its settings, so every branch born from your project gets a consistent lifecycle and compute profile without per-branch flags.

```bash
npm i @neondatabase/config
```

```typescript
// neon.ts
import { defineConfig } from "@neondatabase/config/v1";

export default defineConfig({
  branch: (branch) => {
    if (branch.exists) return {}; // never reconcile existing branches
    if (branch.isDefault) return { protected: true };
    if (branch.name.startsWith("preview/") || branch.name.startsWith("dev")) {
      return {
        parent: "main",
        ttl: "7d", // ephemeral: auto-expire 7 days after creation (max 30d)
        postgres: {
          computeSettings: {
            autoscalingLimitMinCu: 0.25, // scale to zero
            autoscalingLimitMaxCu: 1, // keep throwaway branches cheap
            suspendTimeout: "5m",
          },
        },
      };
    }
    return {};
  },
});
```

The closure receives a read-only descriptor of the target branch — `name`, `exists`, `isDefault`, `parentId`, and more — and returns the tuning to apply: `parent`, `ttl` (auto-expiry), `protected`, and `postgres.computeSettings`. This is the declarative complement to the **Ephemeral lifecycle hygiene** and per-PR / per-test patterns above: instead of remembering `--expires-at` on every `neonctl branches create`, the TTL and compute profile live in version control and apply to every matching branch.

Because `neonctl checkout` applies this policy when it **creates** a branch, a fresh `preview/*` or `dev-*` branch comes up already expiring and scaled-to-zero. Checking out an _existing_ branch doesn't reconcile it — run `neonctl deploy` (alias for `neonctl config apply`) to apply changes to a branch that already exists.

## Branching in CI/CD

Common CI/CD use cases for Neon branches:

- **Per-PR preview deployments:** Branch on PR open, deploy the preview against it, delete on close. Each PR gets an isolated database branch. Injecting the branch's `DATABASE_URL` into the deployed app is hosting-provider-specific — see [preview-branches-with-cloudflare](https://github.com/neondatabase/preview-branches-with-cloudflare), [preview-branches-with-vercel](https://github.com/neondatabase/preview-branches-with-vercel), or [preview-branches-with-fly](https://github.com/neondatabase/preview-branches-with-fly) for tested patterns.
- **Migration testing in CI:** Run risky schema changes against a branch with production-like data before merge.
- **Schema diff visibility:** Use the [schema-diff GitHub Action](https://github.com/marketplace/actions/neon-schema-diff-github-action) to auto-comment a DB-layer diff on the PR.

## Examples

### Example 1: Migration testing with realistic data

**User input:** "I need to test a risky migration against production-like data."

**Agent output shape:**

1. Recommend a normal branch and explain why.
2. Share docs link: https://neon.com/docs/introduction/branching
3. Check the available/authenticated tool path first (MCP, otherwise CLI with `neonctl --version`).
4. Provide commands:
   - `neonctl branches create --name migration-test --parent main --expires-at 2026-12-15T18:02:16Z`
   - `neonctl connection-string migration-test`

### Example 2: Sensitive data development workflow

**User input:** "We cannot copy production data because of compliance."

**Agent output shape:**

1. Recommend schema-only branch and explain why.
2. Share docs link: https://neon.com/docs/guides/branching-schema-only
3. Check the available/authenticated tool path first (MCP, otherwise CLI with `neonctl --version`).
4. Provide command:
   - `neonctl branches create --name compliance-dev --parent main --schema-only --project-id <your-project-id> --expires-at 2026-12-15T18:02:16Z`
5. Mention Beta support path:
   - https://console.neon.tech/app/projects?modal=feedback
   - https://discord.gg/92vNTzKDGp

## Further reading

- https://neon.com/docs/guides/branch-expiration.md
- https://neon.com/docs/guides/neon-github-integration.md
- https://neon.com/docs/ai/neon-mcp-server.md
- https://neon.com/branching