> ## Documentation Index > Fetch the complete documentation index at: https://darwin.so/docs/llms.txt > Use this file to discover all available pages before exploring further. # Act use cases > Coordinate software, browser, human, and transaction work through one durable model. Act is useful whenever work can take time, cross systems, require user input, or pause for authority. Execute software, APIs, MCP servers, and automations. Coordinate scoped work, milestones, and approval. Move campaigns from brief through launch. Deliver decision-ready evidence with traceability. Purchase exact products on reviewed terms. Book providers, times, services, and prices. Confirm reservations, tickets, and activities. Coordinate connected travel reservations. Carry specifications through samples and production. ## Design for interruption Every workflow should survive a lost response, browser closure, client restart, or delayed provider. Persist `actionId`, retry mutations with the same `requestId`, and read the server state before creating replacement work. ## Design for review Show what will happen, who will do it, the current price or quote state, and what authority is required. Use Darwin's structured states instead of presenting a generic success or failure message.