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Capture a screenshot and compact accessibility snapshot of the current page.
The snapshot command is the primary page observation tool. It captures a screenshot and prints a compact accessibility tree for the current page so agents can inspect page structure without sending page state to a separate analysis model. Use snapshot before guessing at selectors, after workflow failures, and whenever the visible page state is unclear.

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Arguments

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ref
string
Optional element ref to scope output to that subtree, for example l16 or e16. Run an unscoped snapshot first; subtree snapshots capture a fresh screenshot but reuse the latest cached tree for that page.

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Required flags

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--session
string
required
The session to snapshot.

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Optional flags

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--page
string
Target a specific page ID within the session. Use npx libretto pages --session <name> to list page IDs when a popup or new tab is open. See pages for details.

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What snapshot produces

For each run, snapshot saves a screenshot under .libretto/sessions/<session>/snapshots/<snapshot-id>/page.png. The command prints:
  • the screenshot path
  • a compact accessibility tree for the page or requested subtree
  • a hint for inspecting subtree refs from the latest full snapshot

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When to use snapshot

  • Before writing a selector. Use snapshot to confirm the element structure rather than guessing.
  • After a workflow step fails. Inspect the exact page state the failure left behind.
  • When the page has rendered content that isn’t obvious from the URL alone.
  • When you need a scoped view of a large page. Run a full snapshot, then inspect relevant refs with snapshot <ref>.
Use ref forms printed in the tree, such as l16. Numeric-suffix aliases such as e16 also match l16.

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Configuration

snapshot does not require AI provider credentials or a configured model. The legacy snapshotModel config key is deprecated and ignored by the default snapshot flow.

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Examples

exec

Run Playwright code to prototype interactions after using snapshot to identify elements.

run & resume

Run a full workflow file and use snapshot to debug failures.