diff --git a/contributions/design-first-ai/design-first-claude-code.md b/contributions/design-first-ai/design-first-claude-code.md
new file mode 100644
index 0000000..b6e8136
--- /dev/null
+++ b/contributions/design-first-ai/design-first-claude-code.md
@@ -0,0 +1,281 @@
+# Design-First AI Collaboration — CLAUDE.md Template & Workflow
+
+A structured approach to AI-assisted development based on Rahul Garg's five patterns published on [martinfowler.com](https://martinfowler.com/articles/reduce-friction-ai/) (Feb–Apr 2026). These patterns shift the experience from correcting a tool to collaborating with a capable teammate.
+
+**Source framework:** [design-first-ai](https://github.com/andresdiegolanda/design-first-ai) (MIT license)
+**Pattern author:** Rahul Garg, Principal Engineer @ Thoughtworks
+
+---
+
+## The Problem
+
+AI coding assistants are like junior developers with infinite energy but zero context. Without project-specific information, they default to generic patterns from training data — producing code that compiles but doesn't fit your project's conventions, architecture, or constraints.
+
+The five patterns solve five failure modes:
+
+| Pattern | Failure mode | Solution |
+|---------|-------------|----------|
+| **Knowledge Priming** | AI uses generic patterns | Load project context before each session |
+| **Design-First Collaboration** | AI collapses design + implementation into one step | Separate design decisions from code |
+| **Context Anchoring** | Decisions are lost when sessions end | Persist decisions in files, not conversations |
+| **Encoding Team Standards** | Senior judgment lives in one head | Version team standards as executable instructions |
+| **Feedback Flywheel** | Same mistakes repeat across sessions | Retrospective after every task improves context |
+
+---
+
+## 1. CLAUDE.md Template
+
+Claude Code auto-loads `CLAUDE.md` from the project root at the start of every session. This is equivalent to Copilot's `.github/copilot-instructions.md` — the single most important file for AI-assisted development.
+
+### Template
+
+Create `CLAUDE.md` in your project root:
+
+```markdown
+# [Project Name] — Claude Code Instructions
+
+> Auto-loaded at session start. Keep under 150 lines.
+> Last reviewed: [date]
+
+---
+
+## Project Identity
+
+[One sentence: what this app does.]
+
+- **Type:** [API / web app / CLI / library / monorepo]
+- **Stack:** [language, framework, key dependencies with versions]
+- **Architecture:** [monolith / microservices / serverless / etc.]
+
+---
+
+## Non-Negotiables
+
+- [Rule 1 — e.g., "No business logic in controllers"]
+- [Rule 2 — e.g., "Constructor injection only — no field injection"]
+- [Rule 3 — e.g., "All public service methods have Javadoc"]
+- [Rule 4 — e.g., "UUID for all entity identifiers — never Long or int"]
+- [Rule 5 — e.g., "Named domain exceptions only — never bare RuntimeException"]
+
+---
+
+## Anti-Patterns — Never Propose These
+
+- [Anti-pattern 1 — e.g., "Do not add @Autowired on fields"]
+- [Anti-pattern 2 — e.g., "Do not add Spring Data or JPA — this project uses in-memory storage"]
+- [Anti-pattern 3 — e.g., "Do not add pagination or sorting unless explicitly asked"]
+- [Anti-pattern 4 — e.g., "Do not wrap services in additional abstraction layers"]
+
+---
+
+## Architecture
+
+[Component] → [Component] → [Storage]
+No [layer that doesn't exist]. [Component] owns the [storage mechanism] directly.
+
+---
+
+## What This Project Is NOT
+
+- Not [thing it's commonly confused with]
+- Not [scope limitation]
+- Not [technology it doesn't use]
+
+---
+
+## File Structure
+
+| Folder | Contains | Rule |
+|--------|----------|------|
+| `src/controllers/` | HTTP handlers | No business logic — delegate to services |
+| `src/services/` | Business logic | Own the data store directly |
+| `src/models/` | Data types, DTOs | Records/value objects only |
+| `tests/` | Unit + integration tests | Mirror src/ structure |
+
+---
+
+## Naming Conventions
+
+- Files: `[kebab-case].ts` or `[PascalCase].java`
+- Classes: `PascalCase` — `ProductService`, `OrderController`
+- Methods: `camelCase` — `createProduct`, `findByCategory`
+- Tests: `[ClassName]Test` — `ProductServiceTest`
+- Test methods: `[method]_[scenario]_[expected]` — `create_validRequest_returnsProduct`
+
+---
+
+## Design Constraints
+
+_This section grows over time through the retrospective technique (see Feedback Flywheel below)._
+
+- [Constraint discovered through use — e.g., "ConcurrentHashMap iteration order is not guaranteed — never rely on insertion order for pagination"]
+- [Constraint discovered through use — e.g., "Record constructors don't support @Valid on nested objects — validate manually"]
+```
+
+### How to generate this from an existing codebase
+
+Instead of filling in the template manually, ask Claude Code to generate it:
+
+```
+Analyze this entire codebase and generate a CLAUDE.md file.
+Be specific to THIS codebase — not generic best practices.
+Include a "Design Constraints" section listing what you should NEVER propose.
+Include an "Anti-Patterns" section with patterns that look valid but break in this project.
+Flag anything non-standard or surprising.
+```
+
+Review the output, correct assumptions, and commit. This takes ~15 minutes.
+
+---
+
+## 2. The Retrospective Command
+
+Create `.claude/commands/retrospective.md`:
+
+```markdown
+After completing this task, answer:
+
+**What context were you missing that would have changed your approach?**
+
+For each answer:
+1. State what you assumed
+2. State what is actually true
+3. Propose the exact line to add to CLAUDE.md (either in Non-Negotiables, Anti-Patterns, or Design Constraints)
+
+Format each as a ready-to-commit addition.
+```
+
+Run this after every completed task — not just when something goes wrong. A session that produced correct output still contains missing context; Claude just happened to guess right.
+
+Each answer becomes a constraint in `CLAUDE.md`. The file compounds — each task makes the next one cheaper.
+
+---
+
+## 3. The Two-Document Workflow
+
+Before writing any code, produce a design document. After writing code, produce a result document. One document captures intention, the other captures result.
+
+### Implementation Guide (before code)
+
+Create `.claude/commands/impl-guide.md`:
+
+```markdown
+Create an implementation guide for this feature as `docs/$ARGUMENTS-impl-guide.md`.
+
+Structure it with these sections:
+
+## Scope
+What this feature does and what it explicitly does NOT do.
+
+## Components
+Each building block with a one-line responsibility. Reuse existing components — do not create unnecessary abstractions.
+
+## Interactions
+How data flows between components. Include error paths.
+
+## Contracts
+Method signatures, parameter types, return types, DTOs. No implementation code — just the interfaces.
+
+Do NOT write any implementation code. This is a design document.
+```
+
+Usage: `/impl-guide SEARCH-ENDPOINT`
+
+### Review checklist (Garg's five dimensions)
+
+Before executing, review the impl-guide against these five questions:
+
+1. **Scope** — Does it match the story? No extra capabilities added?
+2. **Components** — Are existing components reused? No unnecessary abstractions?
+3. **Interactions** — Are error paths documented? Data flow is clear?
+4. **Contracts** — Are signatures complete? Types correct?
+5. **Constraints** — Does it respect everything in CLAUDE.md?
+
+Iterate until every section is correct. Then execute.
+
+### Execution Report (after code)
+
+Create `.claude/commands/execution-report.md`:
+
+```markdown
+Create an execution report as `docs/$ARGUMENTS-execution-report.md`.
+
+Include:
+- What was implemented and where (file paths)
+- Deviations from the impl-guide and why
+- How to run the application
+- How to run the tests
+- A compliant commit message
+```
+
+Usage: `/execution-report SEARCH-ENDPOINT`
+
+### Why two documents
+
+The impl-guide and execution-report together solve two patterns at once:
+
+- **Design-First Collaboration:** The impl-guide forces design decisions before code. Corrections caught here cost a sentence to fix. The same correction after implementation costs a rewrite.
+- **Context Anchoring:** Both documents persist on disk. They survive session boundaries, IDE restarts, and engineer changes. The next person reads the documents, not the chat history.
+
+---
+
+## 4. How It All Fits Together
+
+```
+ONBOARDING (once, ~15 minutes)
+────────────────────────────────────────
+Ask Claude Code to generate CLAUDE.md
+from your existing codebase.
+Review, correct, commit.
+
+FOR EACH FEATURE
+────────────────────────────────────────
+CLAUDE.md ← auto-loaded every session
+
+   /impl-guide FEATURE-NAME
+          ↓
+   Review against 5 dimensions
+   Iterate until correct
+          ↓
+   Claude executes the guide
+          ↓
+   Code + /execution-report FEATURE-NAME
+
+AFTER EVERY TASK
+────────────────────────────────────────
+   /retrospective
+          ↓
+   Add answers to CLAUDE.md
+   (Design Constraints section grows)
+   Commit the change.
+```
+
+---
+
+## Example: What the retrospective produces
+
+After building a search endpoint, running `/retrospective` might surface:
+
+```
+ASSUMED: Long for product IDs (Java default)
+ACTUAL: This project uses UUID for all identifiers
+
+→ Add to CLAUDE.md Non-Negotiables:
+  "UUID for all entity identifiers — never Long or int"
+
+ASSUMED: Spring Data Pageable for pagination
+ACTUAL: This project doesn't use Spring Data — manual pagination with stream/skip/limit
+
+→ Add to CLAUDE.md Anti-Patterns:
+  "Do not add Spring Data or JPA dependencies"
+```
+
+Both additions prevent the same mistakes in every future session, for every developer on the team.
+
+---
+
+## References
+
+- **Garg's articles:** [martinfowler.com/articles/reduce-friction-ai](https://martinfowler.com/articles/reduce-friction-ai/)
+- **Framework repo:** [github.com/andresdiegolanda/design-first-ai](https://github.com/andresdiegolanda/design-first-ai) (MIT license, v1.5.0)
+- **Patterns:** Knowledge Priming (Feb 24), Design-First Collaboration (Mar 3), Context Anchoring (Mar 17), Encoding Team Standards (Mar 24), Feedback Flywheel (Apr 8)