interactive-story/planning/DECISIONS/008-phase0-before-build-plan.md

ADR 008 — Complete Phase 0 Before Detailed Build Planning

Status: Accepted and completed

Decision

The project completed repository research, validation, architecture selection, and critical prototypes before finalizing the detailed production implementation milestone plan.

Context

Multiple candidate open-source projects implemented overlapping parts of the desired system. The correct build sequence depended on which codebase survived local validation.

Alternatives Considered

• write full implementation plan immediately,
• begin coding against the first plausible project,
• perform a bounded Phase 0 and then finalize the build plan.

Reason

The bounded Phase 0 prevented false assumptions from becoming production architecture. In particular, runtime testing discovered destructive AI-DnD Undo, an offline tokenizer fetch, remote fonts, Open Dungeon's lack of tests and destructive summary/history assumptions, and the relative-delta state-protocol failure mode.

Completion Record

Phase 0 selected AI-DnD as the production base, validated the non-destructive head-cursor approach, selected explicit typed narrative-state events, established local-only hardening requirements, and produced the production BUILD-MILESTONES.md.

Consequences

• the placeholder build plan has been replaced by a production milestone sequence,
• SPECIFICATION.md and TECHNICAL-DESIGN.md are the v1.0 planning baseline,
• production coding still requires explicit authorization and a milestone-specific prompt,
• the current review intentionally stops before preparing that prompt.