# Preliminary Engineering Plan

This plan supports estimation and foundational work only. It intentionally avoids production architecture decisions that the design program has not earned.

## Phase E0 — Evidence lock and walkthrough

Outcome: the team can walk all eleven designs and distinguish canonical requirements, accepted constraints, current evidence, proposals, and unknowns.

Completion criteria:

- every engineer can locate the source and acceptance evidence for each scene;
- contradictions and missing authority are entered in a shared decision register;
- no fixture is represented as production truth.

## Phase E1 — Shared experience foundations

Outcome: reusable visual and interaction foundations can reproduce the hierarchy, warmth, clarity, and accessibility of the reviewed scenes.

Completion criteria:

- typography, spacing, color roles, focus treatment, reduced motion, and contrast have measurable baselines;
- the Studio shell can express one active Realm, one Focus, one conversation, and up to three elevated objects;
- no permanent navigation or operational dashboard is introduced.

## Phase E2 — Trust-bearing interaction primitives

Outcome: Sources, permissions, Gates, contributions, decisions, and Records have explicit visible states independent of any one Realm.

Completion criteria:

- every consequential action can show authority, scope, state, confirmation, and resulting Record;
- provenance, uncertainty, visibility, correction, and retention can be represented without crowding the default surface;
- exceptional-state implementation is deferred until Gate 2B.2 evidence exists.

## Phase E3 — Conversation and contextual-instrument foundation

Outcome: a continuous conversation can reveal, operate, and dismiss contextual instruments without becoming a collection of screens.

Completion criteria:

- a user can move from conversation to instrument and back without losing context;
- Sources or Elements can be attached, previewed, expanded, and returned;
- hidden machinery stays hidden unless relevant or requested.

## Phase E4 — Fixture and validation harness

Outcome: engineering can test reviewed behaviors using deterministic fictional scenarios.

Completion criteria:

- fixtures are isolated from production services and secrets;
- each P0 user story has a deterministic normal-state test;
- authority-sensitive stories are blocked from production claims until policy evidence exists.

## Phase E5 — Planning review

Outcome: product, design, governance, and engineering agree what may proceed before Gate 2B.2 and what must wait.

Completion criteria:

- estimates expose assumptions and open decisions;
- reversible foundational work is separated from feature implementation;
- all deferred work names the design gate or authority evidence that unlocks it.
