developerinlondon/project-planning

Project Planning

When NOT to Use

• Trivial single-file changes or bug fixes
• Features that fit entirely in one file
• Refactors with no architectural decisions

Process

1. Ask clarifying questions to understand the project idea fully
2. Create 00-plan.md first -- get approval before continuing
3. Create 01-architecture.md -- get approval for the technical design
4. Create remaining plan files
5. Create AGENTS.md last (it summarises decisions from the plan files)
6. Set up dprint.json for markdown formatting

Directory Structure

.claude/plans/
├── 00-brainstorm/          (optional: early-stage research)
│   └── 00-plan.md
└── 01-implementation/
    ├── 00-plan.md          (overview, problem, solution, estimates)
    ├── 01-architecture.md  (system design, ASCII diagrams, data flow)
    ├── 02-file-structure.md (module/package/crate layout)
    ├── 03-roadmap.md       (sprints with tasks and time estimates)
    ├── 04-wireframes.md    (optional: UI screens in ASCII art)
    └── 05-user-workflows.md (optional: end-to-end user scenarios)

What Goes in Each File

00-plan.md

Include a header block with: created date, status, repo name, and links to the other plan files.

Body covers:

• Problem statement (what pain does this solve?)
• What makes it unique (vs existing tools)
• Target users and their context
• Integration points with other systems
• All time estimates in AI agent time (see Estimation Rules below)

01-architecture.md

• High-level system diagram in ASCII (NOT Mermaid)
• Module/crate dependency graph
• Data flow diagrams
• Database schema (if applicable)
• Key traits, interfaces, or contracts

Wrap every diagram in a triple-backtick code block with no language tag.

02-file-structure.md

Full directory tree with inline annotations explaining each module's purpose.

• Rust projects: workspace layout + per-crate breakdown
• TypeScript projects: package structure + key files
• Annotate non-obvious directories with a short comment

03-roadmap.md

Break implementation into numbered sprints. Sprint 0 is always project scaffolding. The final sprint is always polish and release prep.

Each sprint includes:

• Numbered task list with per-task AI time estimates
• Sprint total estimate
• Quality gate: what must pass before the next sprint starts
• Dependencies on other sprints

04-wireframes.md (optional)

ASCII art wireframes for each UI screen or view. Include a navigation flow diagram showing how screens connect. One diagram per screen.

05-user-workflows.md (optional)

Step-by-step scenarios showing how a user accomplishes a goal end-to-end. Cover the happy path and at least one error or edge case per workflow.

Estimation Rules

• NEVER give human developer time estimates
• All estimates are AI agent time: 16h/day throughput, roughly 4x human speed
• Include per-task estimates AND sprint totals
• Sprint 0 (scaffolding) is typically 2-3 hours AI time
• Label estimates clearly: [AI: 1.5h] or [AI: 30min]

AGENTS.md

Create at the repo root after the plan files are approved. Include:

• Project context: name, repo, current phase, active branch, plan file locations
• Post-edit hooks: formatter command, ASCII box fixer if used
• Key architecture decisions: bullet points, one decision per line
• Anti-patterns: things to NEVER do in this codebase (specific to this project)
• Dependencies: key libraries and the reason each was chosen

Diagram Rules

• ASCII only -- no Mermaid, no SVG, no image files
• Box-drawing characters: +, -, |, /, \, >, <
• Max ~40 lines tall, ~80 chars wide per diagram
• Data flow: use ----> arrows with labels
• Hierarchy: use +-- and | tree notation
• Always wrap in triple-backtick code blocks