junior snapshot create

Use junior snapshot create when your deployment needs the sandbox runtime dependencies ready before the app starts handling work. This is the command you wire into build-time snapshot warmup.

Usage

Run it from a project that already has @sentry/junior installed:

pnpm exec junior snapshot create

The command takes no extra arguments.

What it does

Before resolving the snapshot, the CLI inspects the loaded plugins and summarizes the snapshot inputs:

• Plugin names
• Runtime system dependencies
• Runtime npm dependencies
• Runtime postinstall commands

It then resolves the sandbox snapshot profile, reuses a cached snapshot when possible, or rebuilds the snapshot when the profile changed.

Example output

Typical logs look like this:

Loaded plugins (2): agent-browser, notion
Sandbox snapshot inputs: plugins=1 system_dependencies=1 npm_dependencies=1 postinstall_commands=1
Snapshot plugins (1): agent-browser
System dependencies (1): gtk3
NPM dependencies (1): agent-browser@latest
Runtime postinstall (1): agent-browser install
Resolving sandbox snapshot profile...
Building sandbox snapshot...
Sandbox snapshot create complete: runtime=node22 resolve_outcome=rebuilt cache_hit=false dependency_count=2 profile_hash=abc snapshot_id=snap_123 rebuild_reason=cache_miss

If there is nothing to snapshot, the command still reports the empty profile and completion outcome.

The common case is a Vercel build command:

package.json

{
  "scripts": {
    "build": "junior snapshot create"
  }
}

Use this when your enabled plugins declare runtime dependencies or postinstall steps that should be prepared ahead of request handling.

Failure behavior

If snapshot resolution fails, the CLI exits non-zero and prints the underlying error:

junior command failed: OIDC missing

Treat that as a real deploy blocker. The usual checks are the build environment, REDIS_URL, and any platform auth required for snapshot creation.

Verification

After adding the command to your build:

1. Run pnpm exec junior snapshot create locally or in CI.
2. Confirm the final log line includes Sandbox snapshot create complete.
3. Verify the reported dependency counts match the plugins you enabled.

Next step

Run junior check before snapshot warmup when you change plugin.yaml or SKILL.md, then wire the command into Vercel from Quickstart.