- Section 3.5 "Team Configuration at Scale" in ultimate-guide.md: profiles YAML + shared modules + skeleton + assembler script; 59% context token reduction measured on 5-dev production team; includes CI drift detection, 5-step replication guide, trade-offs - New workflow: guide/workflows/team-ai-instructions.md (6 phases, scaling thresholds, troubleshooting table) - New templates: examples/team-config/ (profile-template.yaml, claude-skeleton.md, sync-script.ts) - reference.yaml: 9 new entries for team_ai_instructions_* - README: templates count 161 → 164, date Feb 19 → Feb 20 - CHANGELOG [Unreleased]: resource evaluations (AGENTS.md ETH Zürich 4/5, Sylvain Chabaud 3/5), spec-first Task Granularity section, methodologies ATDD expansion Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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| title | description | tags | ||||
|---|---|---|---|---|---|---|
| Team AI Instructions Management | Scale CLAUDE.md across a multi-developer team using Profile-Based Module Assembly |
|
Team AI Instructions Management
Manage AI instructions (CLAUDE.md, .cursorrules) across a team without fragmentation.
Pattern: Profile-Based Module Assembly — shared modules + per-dev profiles + automated assembler.
When to use: Team 5+ developers, multiple AI tools (Claude Code + Cursor/Windsurf), mixed OS. Skip if: Solo developer, homogeneous team (same tool, same OS), short project (<3 months).
The Problem: N x M x P Fragmentation
When a team grows, AI instructions fragment fast:
| Factor | Values | Example |
|---|---|---|
| N developers | 5-20 | Alice, Bob, Charlie... |
| M tools | 2-4 | Claude Code, Cursor, Windsurf, Copilot |
| P operating systems | 2-3 | macOS, Linux, WSL |
Total variants: N x M x P = 5 x 3 x 2 = 30 possible configurations.
Without a system, what happens:
Week 1: Team agrees on shared CLAUDE.md
Week 3: Alice adds TypeScript strict rules locally
Week 5: Bob copies Alice's file, removes half the rules
Week 8: New hire Charlie gets Bob's outdated copy
Week 12: 5 developers, 5 different CLAUDE.md files, nobody knows what's canonical
Root cause: CLAUDE.md is treated as a monolithic file instead of a composed configuration.
Architecture Overview
profiles/ modules/
├── alice.yaml ├── core-standards.md
├── bob.yaml ├── git-workflow.md
├── charlie.yaml ├── typescript-rules.md
│ ├── test-conventions.md
│ ├── macos-paths.md
│ ├── linux-paths.md
│ ├── cursor-rules.md
│ └── communication-verbose.md
│
├── skeleton/
│ └── claude-skeleton.md ← Template with {{MODULE:name}} placeholders
│
└── sync-ai-instructions.ts ← Reads profile → injects modules → writes output
│
▼
output/
├── alice/CLAUDE.md ← Generated (read-only)
├── bob/CLAUDE.md
└── charlie/CLAUDE.md
Flow: Profile (YAML) + Skeleton (template) + Modules (fragments) → Assembler → Generated CLAUDE.md
Phase 1: Audit Your Current CLAUDE.md
Goal: Classify every line as universal, conditional, or personal.
# Audit template
## Universal (all devs, all tools)
- Architecture: hexagonal
- Tests: must pass before PR
- Naming: kebab-case for files
## Conditional (depends on tool or OS)
- Cursor: use @filename syntax → module: cursor-rules
- macOS paths: /opt/homebrew → module: macos-paths
- Linux paths: /usr/local → module: linux-paths
## Personal (individual preference)
- Style: verbose explanations → profile preference
- Language: French comments → profile preference
Command to measure:
wc -l CLAUDE.md # Total lines before modularization
# Tag each line with [U]niversal, [C]onditional, [P]ersonal
# Count by category to estimate module split
Typical result: 60% universal, 25% conditional, 15% personal.
Phase 2: Extract Modules
Goal: One .md file per thematic group.
Recommended structure:
modules/
├── core-standards.md # Architecture, naming, patterns (all devs)
├── git-workflow.md # Git conventions (all devs)
├── typescript-rules.md # TS strict config (if TypeScript)
├── test-conventions.md # Testing patterns (all devs)
├── macos-paths.md # macOS-specific paths (if macOS)
├── linux-paths.md # Linux paths (if Linux)
├── cursor-rules.md # Cursor-specific rules (if Cursor)
└── communication-verbose.md # Verbose explanation style (if preferred)
Module format (each module is a standalone Markdown fragment):
<!-- modules/typescript-rules.md -->
## TypeScript Rules
- Use strict mode: `"strict": true` in tsconfig
- Prefer `type` over `interface` for unions
- No `any` — use `unknown` + type guards
- Zod for runtime validation at boundaries
Guidelines:
- Keep modules self-contained (no cross-references between modules)
- 15-50 lines per module is the sweet spot
- Name modules for their domain, not their audience
- One module = one reason to change
Phase 3: Create Developer Profiles
Goal: One YAML per developer, listing their modules.
# profiles/alice.yaml
name: "Alice"
os: "macos"
tools:
- claude-code
- cursor
communication_style: "concise"
modules:
core:
- core-standards
- git-workflow
- typescript-rules
- test-conventions
conditional:
- macos-paths # auto-included when os: macos
- cursor-rules # auto-included when cursor in tools
preferences:
language: "english"
Profile rules:
coremodules: included for every dev (team standards)conditionalmodules: included based onosandtoolsfieldspreferences: personal settings injected into skeleton variables
Template for new team members: See profile-template.yaml
Phase 4: Write the Assembler Script
Goal: Script that reads profile, injects modules, outputs CLAUDE.md.
// sync-ai-instructions.ts (simplified ~30 lines)
import { readFileSync, writeFileSync, mkdirSync } from 'fs';
import { parse } from 'yaml';
import { join } from 'path';
const profile = parse(readFileSync(`profiles/${process.argv[2]}.yaml`, 'utf8'));
let skeleton = readFileSync('skeleton/claude-skeleton.md', 'utf8');
// Collect modules from profile
const modules = [...profile.modules.core, ...profile.modules.conditional];
// Replace each placeholder with module content
for (const mod of modules) {
const content = readFileSync(`modules/${mod}.md`, 'utf8');
skeleton = skeleton.replace(`{{MODULE:${mod}}}`, content);
}
// Remove unused placeholders
skeleton = skeleton.replace(/\{\{MODULE:\w+\}\}/g, '');
// Write output
const outDir = `output/${process.argv[2]}`;
mkdirSync(outDir, { recursive: true });
writeFileSync(join(outDir, 'CLAUDE.md'), skeleton);
console.log(`Generated ${outDir}/CLAUDE.md (${modules.length} modules)`);
Run:
npx ts-node sync-ai-instructions.ts alice # Single dev
npx ts-node sync-ai-instructions.ts --all # Generate all profiles
npx ts-node sync-ai-instructions.ts --check # Verify no drift
Full template: sync-script.ts
Phase 5: CI Drift Detection
Goal: Catch when output files are out of sync with profiles/modules.
# .github/workflows/ai-instructions-check.yml
name: AI Instructions Drift Check
on:
push:
paths:
- 'modules/**'
- 'profiles/**'
- 'skeleton/**'
schedule:
- cron: '0 9 * * 1-5' # Weekdays at 9am
jobs:
check-drift:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v4
- run: npx ts-node sync-ai-instructions.ts --check
- name: Fail if drift detected
run: |
if git diff --quiet output/; then
echo "No drift detected"
else
echo "::error::AI instructions are out of sync!"
git diff output/
exit 1
fi
What it detects:
- A module was edited but the assembler wasn't re-run
- A profile was added but no output CLAUDE.md exists
- A dev manually edited their generated CLAUDE.md
Policy: Generated files are read-only. All changes go through profiles/modules, then re-run the assembler.
Phase 6: Onboarding New Developers
Goal: New dev gets their CLAUDE.md in under 5 minutes.
# 1. Clone repo
git clone <repo>
# 2. Copy profile template
cp examples/team-config/profile-template.yaml profiles/dave.yaml
# Edit: name, os, tools, modules
# 3. Generate
npx ts-node sync-ai-instructions.ts dave
# 4. Install
cp output/dave/CLAUDE.md .claude/CLAUDE.md
CLAUDE.md placement reminder:
- Project-wide:
project/CLAUDE.md(committed, for team conventions) - Personal overrides:
.claude/CLAUDE.md(gitignored, for individual preferences)
Troubleshooting
| Problem | Cause | Fix |
|---|---|---|
| Generated file too long | Too many modules included | Review profile: remove rarely-used modules |
| Module missing in output | Placeholder typo in skeleton | Check {{MODULE:name}} matches filename |
| CI drift alert | Output not regenerated after module edit | Run sync-ai-instructions.ts and commit |
| Dev A has rules Dev B doesn't | Expected — it's the point | Verify profile is correct for that dev |
| Stale output after merge | Merge didn't trigger regeneration | Run assembler post-merge (add git hook) |
Scaling Thresholds
| Team size | Approach |
|---|---|
| 1-2 devs | Shared CLAUDE.md + precedence rules (Section 3.4) |
| 3-5 devs, same tools | Optional: modules only, no profiles |
| 5+ devs or multi-tool | Profile-Based Module Assembly (this workflow) |
| 20+ devs | Consider a CLAUDE.md config server + PR-based module changes |
Measured Results
From a production team (5 developers, 3 tools, 2 OS):
| Metric | Before | After |
|---|---|---|
| Lines per CLAUDE.md | ~380 (monolithic) | ~185 (assembled) |
| Token reduction | — | 59% less context consumed |
| Modules extracted | 0 | 12 |
| Onboarding time | "copy someone's file" | 5 min (template + generate) |
| Drift incidents | Weekly | 0 (CI catches) |
Related
- Section 3.5 Team Configuration at Scale — Concept overview and measured results
- Section 3.4 Precedence Rules — How Claude reads multiple CLAUDE.md files
- profile-template.yaml — Profile template
- claude-skeleton.md — Skeleton template
- sync-script.ts — Full assembler script