Stages & gates
A process = a sequence (or DAG) of free-execution regions (stages) separated by verifiable checkpoints (gates). The gate fixes what counts as done; the stage leaves how free.
This is where script (control #1) finds its right use: you script the macro skeleton (the ordered stages — conserved, owner-authored) and gate the boundaries, while the executor stays free inside each stage. Not "script everything" (driver) nor "gate everything" — script the conserved structure, free the volatile execution.
Three principles
- Separate "done" from "how" — the gate (stable, domain/owner-defined) vs the stage (volatile, the executor's variety); decoupled, so one changes without disturbing the other.
- Gates destroy variety, stages create it (Ashby) — stages fan possibilities open, gates cut to the passing branch; the process pulses fan-out → converge (Cooper's "funnel").
- Script the conserved, free the volatile — phases are domain-level (model-independent), so scripting them is safe; execution is model-dependent, so it must stay free. "Scripts depreciate with the model" only bites if you scripted the execution.
Inside
- necessity — why large tasks need it (Simon / error-compounding / real-options / Boehm / Cooper)
- stage-anatomy — what a stage contains: the injection (goal + context + playbook + tools)
- formalizations — five lenses on the same skeleton
- prior-art-is-our-base-case — the prior art already had our P×C stopping rule (reads prior-art-task-decomposition, now wiki)
- failure-modes — funnel→tunnel, gaming the gate, wrong granularity
- steering-without-control — the soft gate: steering when the agenda is theirs and hidden
- mechanical-stage-gate — the AI-executor instance (vibe-linter)
- gate-theory — what a gate is: a δ-neighborhood around a necessary waypoint of the reliable success paths; deviation = observable δ; the bridge to relaxation and convergence.
Established name: Stage-Gate (R. G. Cooper, new-product development) — stages of work + go/kill gates.