Part 4 of 7|April 2026|5 min
The $0.04 Assembly
EconomicsPipeline
The numbers
Old: one model, sequential. 25 seconds, $0.30, blank screen.
New: five steps, three models. First object in 3 seconds, $0.04 total.
The pipeline
Compose Workflow
reasoningfast/cheapdeterministic
#StepModelLatencyCost
1
PlanSonnet
1.5s$0.0152
FlattenDeterministic
<0.1s$03
Fabricate ×NHaiku (concurrent:10)
0.5s$0.0054
RegroupDeterministic
<0.1s$05
RefineSonnet
2s$0.0106
LightSonnet
0.8s$0.0087
CameraPure JS
<1ms$0Total
~6s end-to-end·$0.038
Watch it build
NDJSON Stream
Click "Compose" to start the pipeline
Simulated compose pipeline. In production, each line is a real NDJSON event from Mastra workflows via Sonnet (plan, refine) and Haiku (fabricate, light).
Streaming NDJSON. Real GLB parts. Phase badges showing progress.
The concurrency trick
Sonnet sequential: 12 × 1s = 12s. Haiku parallel: concurrent:10 = 0.5s. Haiku is 20× cheaper and we run 10 in parallel.
The refinement tax
We tried skipping it. 30% of scenes had visible errors. $0.015 is the cheapest QA engineer you'll ever hire.
Cost and latency
Cost & Latency: Before vs After
Plan
Fabricate
Refine
Light
Old (single call)