# Milestone 2 completion evidence

Date: 2026-07-19
Decision: promoted
Workflow: `build_week_vnext`
Artifact contract: `vnext-2026-07-19`

## Outcome

Chartsmith now accepts a chart image alone and autonomously produces one
persuasion-first redesign. GPT-5.6 performs reconstruction, concept selection,
render direction, visual review, repair, and final comparison. GPT Image 2 may
create a non-data-bearing visual base; deterministic Python owns exact text and
quantitative geometry.

All three fixed Milestone 2 cases passed the production, epistemic, material
communication, authorship, and GPT-5.6 provenance gates at full and embedded
sizes.

Live validation used official Codex CLI 0.144.6. The documented bootstrap
downloaded that release, verified its published archive digest, and returned the
isolated executable path successfully.

| Case | Accepted run | Final idea | Repairs | Final review highlights |
| --- | --- | --- | ---: | --- |
| A: ordinary | `milestone2-case-a-20260719-004` | Opposing endpoint chambers with a registered interior lens | 2 | clarity 5/5; hierarchy 5/5; no defects |
| B: dense | `milestone2-case-b-20260719-001` | One signal tower above a ranked field, with explicit mean split | 3 | clarity 5/5; authorship 5/5; fidelity 5/5 |
| C: already strong | `milestone2-case-c-20260719-001` | Monitor-view triptych retaining every observation and interval | 6 | clarity 5/5; hierarchy 5/5; no defects |

Canonical evidence is under `runs/build_week/vnext/<run-id>/`. Curated copies are
under `examples/build_week_vnext/`.

## Mechanism-level learning

The first Case A attempt forwarded a 24,266-character reconstruction into every
stage and timed out during concept generation. The retained fix keeps the full
analysis artifact but sends stage-specific context:

- Case A: concept context reduced 69.88%, render context 49.69%, review context
  85.03%; every reconstructed mark remained in render context.
- Case B: repair context reduced 42.54% on the first repair and 43.34% on the
  second while preserving the complete renderer and review findings.
- Challenge: review context reduced 78.75%; repair contexts fell by roughly
  48-50%.

Two orchestration hardenings also came directly from live failures:

- identical GPT Image requests are content-addressed and reuse a validated
  generated base instead of making redundant network calls;
- a failed image-generation or interrupted repair run can resume from its latest
  artifacts without repeating reconstruction and concept work.

The original two-repair assumption was rejected by evidence. The active bound is
six repairs plus one pivot because an already-strong dense source needed several
separate epistemic, typography, annotation, and metaphor corrections. Release
still depends on the independent hard gates; the larger bound does not weaken
them.

## Promotion rationale

The vertical slice satisfies the Milestone 2 stop conditions:

- image-only input and no user design decisions;
- one-shot deterministic orchestration with recorded bounds;
- three materially authored accepted examples;
- zero visible production defects in final full and embedded renders;
- explicit uncertainty and epistemic-floor preservation;
- GPT-5.6 provenance in every accepted run;
- reproducible current Codex setup and documented command.

The v2.6 workflow remains a rollback baseline. Milestone 3 can now build the
judge-facing product surface without redesigning the core workflow.
