Run a takeoff

From start to finish: plan upload, then the AI assessment, then symbols on the canvas. The same sequence ships as an MCP prompt (takeoff_from_plans) and as an Arazzo workflow.

Steps

1. Create a project (or use an existing one). Upload a plan PDF via POST /v1/files + the presigned R2 URL.
2. POST /v1/projects/{id}/assessments starts an AI pass that runs in the background. A project runs one takeoff at a time: a second start while one is running answers 409 ANALYSIS_IN_PROGRESS.
3. Poll GET /v1/assessments/{id} until status === "complete". Or subscribe to the assessment.completed webhook event.
4. The measured elements are symbols. Use GET /v1/projects/{id}/line-items to see what's now bound.

Don't

• Don't re-run the assessment to "refresh" quantities; re-count from the existing symbols instead, or it'll wipe user edits.