# Project Context

*Last updated: [DATE]*

## Current State

- Phase: [current development phase]
- Working on: [current task or feature]
- Blockers: None

## Key Rules (Quick Reference)

<!-- DX-54: Rules summary for long conversation resilience -->

### Core/Shell Separation
- **Core** (`**/core/**`): @pre/@post + doctests, NO I/O imports
- **Shell** (`**/shell/**`): Result[T, E] return type
### USBV Workflow
1. Understand → 2. Specify (contracts first) → 3. Build → 4. Validate

### Verification
- `invar_guard()` = static + doctests + CrossHair + Hypothesis
- Final must show: `✓ Final: guard PASS | ...`

## Task Router (DX-62)

<!-- Before writing code, check this table -->


| If you are about to... | STOP and read first |
|------------------------|---------------------|
| Write code in `core/` | `.invar/examples/contracts.py` |
| Write code in `shell/` | `.invar/examples/core_shell.py` |
| Add `@pre`/`@post` contracts | `.invar/examples/contracts.py` |
| Use functional patterns | `.invar/examples/functional.py` |
| Implement a feature | `.invar/examples/workflow.md` |


**Rule:** Match found above? Read the file BEFORE writing code.

## Self-Reminder

<!-- DX-54: AI should re-read this file periodically -->

**When to re-read this file:**
- Starting a new task
- Completing a task (before moving to next)
- Conversation has been going on for a while (~15-20 exchanges)
- Unsure about project rules or patterns

**Quick rule check:**
- Am I in Core or Shell?
- Do I have @pre/@post contracts?
- Am I following USBV workflow?
- Did I run guard before claiming "done"?

---

## Recent Decisions

1. [Decision summary] - [Brief rationale]

## Lessons Learned

1. [Pitfall or issue] → [Solution or workaround]

## Documentation Structure

| File | Owner | Edit? | When to Read |
|------|-------|-------|--------------|
| INVAR.md | Invar | No — use `invar update` | Protocol details, Six Laws |
| CLAUDE.md | User | Yes | Project rules |
| .invar/context.md | User | Yes (this file) | Session start, refresh |
| .invar/examples/ | Invar | No | Learning Core/Shell patterns |

**Decision rule:** Is this Invar protocol or project-specific?
- Protocol content → Already in INVAR.md, don't duplicate
- Project-specific → Add to CLAUDE.md or here

**When to consult INVAR.md:**
- Unsure about Core/Shell separation rules
- Need to understand Six Laws principles
- Checking USBV workflow details

## Technical Debt

*Run `invar_guard()` to check current status.*


| File | Warning | Priority |
|------|---------|----------|
| (none) | — | — |

## Key Files

| File | Purpose |
|------|---------|
| INVAR.md | Protocol reference (Invar-managed) |
| CLAUDE.md | Project guide (customize freely) |
| src/core/ | Pure business logic |
| src/shell/ | I/O adapters |

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*Update this file when: completing major tasks, making design decisions, discovering pitfalls.*
