4.3The Disk-First Architecture

The key design decision — and the reason for the token savings — is where browser state goes:

	Playwright MCP	Playwright CLI
Page snapshot	Streamed into LLM context on every action	Saved to disk as YAML; agent gets a file path
Screenshots	Returned inline (base64 in tool response)	Saved to .playwright-cli/; read only if needed
Who decides what the LLM sees	The protocol (everything, always)	The agent (reads files on demand)
Context growth per step	Thousands of tokens	Dozens of tokens

The agent decides what it needs to read. A 20-step flow where the agent only inspects the page twice costs two snapshot reads — not twenty.