Windsurf Reference Architecture

┌──────────────────────────────────────────────────────┐
│              Windsurf Workspace                       │
│  ┌───────────────┐  ┌────────────────────────────┐    │
│  │ .devin/rules/project.md│  │ .windsurf/                 │    │
│  │ (AI context)  │  │  ├── rules/ (trigger rules)│    │
│  │               │  │  ├── workflows/ (automation)│    │
│  │               │  │  └── settings.json         │    │
│  └───────────────┘  └────────────────────────────┘    │
│  ┌───────────────┐  ┌────────────────────────────┐    │
│  │ .codeiumignore│  │ ~/.codeium/                │    │
│  │ (index rules) │  │  ├── global_rules.md       │    │
│  │               │  │  ├── windsurf/memories/    │    │
│  │               │  │  └── windsurf/mcp_config   │    │
│  └───────────────┘  └────────────────────────────┘    │
├──────────────────────────────────────────────────────┤
│              Cascade AI Engine                        │
│  ┌───────────┐  ┌───────────┐  ┌─────────────────┐   │
│  │ Super-    │  │ Cascade   │  │ Command         │   │
│  │ complete  │  │ Write/Chat│  │ (Inline Edit)   │   │
│  │ (Tab)     │  │ (Cmd+L)  │  │ (Cmd+I)         │   │
│  └───────────┘  └───────────┘  └─────────────────┘   │
├──────────────────────────────────────────────────────┤
│              Context Layers                           │
│  Rules > Memories > @Mentions > Open Files > Index   │
└──────────────────────────────────────────────────────┘

my-project/
├── .devin/rules/project.md              # AI context (stack, patterns, constraints)
├── .codeiumignore              # Indexing exclusions
├── .windsurf/
│   ├── settings.json           # IDE settings (committed)
│   ├── rules/
│   │   ├── testing.md          # trigger: glob **/*.test.ts
│   │   ├── api-routes.md       # trigger: glob src/routes/**
│   │   ├── security.md         # trigger: model_decision
│   │   └── migrations.md       # trigger: manual
│   └── workflows/
│       ├── new-feature.md      # /new-feature
│       ├── deploy-staging.md   # /deploy-staging
│       ├── review-pr.md        # /review-pr
│       └── quality-check.md    # /quality-check
├── src/
│   ├── routes/                 # API route handlers
│   ├── services/               # Business logic
│   ├── repositories/           # Data access
│   └── types/                  # Shared types
├── tests/
│   ├── fixtures/               # Test data factories
│   └── services/               # Service unit tests
└── docs/
    └── architecture.md         # Architecture decisions

# Priority order (highest to lowest):
rules_hierarchy:
  1_global_rules:
    path: ~/.codeium/windsurf/memories/global_rules.md
    limit: 6000 chars
    scope: All workspaces
    use_for: "Personal coding preferences, universal standards"

  2_workspace_rule:
    path: .devin/rules/project.md (project root)
    limit: 12000 chars
    scope: Current workspace
    use_for: "Project stack, architecture, conventions"

  3_location_scoped_rules:
    path: .devin/rules/*.md or AGENTS.md in subdirectories
    limit: 12000 chars each
    scope: Triggered by glob, model_decision, or manual
    use_for: "File-type-specific patterns, conditional rules"

  4_memories:
    path: ~/.codeium/windsurf/memories/
    scope: Workspace-specific (auto-generated)
    use_for: "Decisions, discoveries (supplement, don't replace rules)"

# Total active chars: 12000 max (global + workspace rules combined)
# If exceeded: global rules take priority, workspace rules truncated

// .windsurf/settings.json (committed to git)
{
  "codeium.indexing.excludePatterns": [
    "node_modules/**", "dist/**", ".next/**",
    "coverage/**", "*.min.js", "**/*.map"
  ],
  "codeium.autocomplete.enable": true,
  "editor.formatOnSave": true,
  "editor.defaultFormatter": "biomejs.biome",
  "typescript.tsdk": "node_modules/typescript/lib",
  "files.associations": { "*.css": "tailwindcss" }
}

monorepo/
├── .devin/rules/project.md              # Shared conventions (brief)
├── .codeiumignore              # Broad exclusions
├── apps/
│   ├── web/
│   │   └── .devin/rules/project.md      # Next.js-specific rules
│   └── mobile/
│       └── .devin/rules/project.md      # React Native rules
├── packages/
│   ├── api/
│   │   └── .devin/rules/project.md      # Express/Fastify rules
│   └── shared/
│       └── .devin/rules/project.md      # Library conventions
└── .windsurf/
    └── workflows/              # Cross-package workflows

# BEST PRACTICE: Open apps/web/ or packages/api/ directly
# NOT the monorepo root
# Cascade gets focused context per workspace window

## What to Pin in Cascade

Pin files that provide essential context:
- Type definition files (types/*.ts)
- Architecture decision records (docs/adr/)
- API schema files (openapi.yaml)
- Database schema (prisma/schema.prisma, drizzle/schema.ts)

How to pin:
- Click the pin icon next to a file in the Cascade context area
- Pinned files are always included in Cascade's context window
- Limit: pin 3-5 files max (more = diluted context)

# Project: Inventory API
Stack: TypeScript, Fastify, and PostgreSQL.
Testing: Run Vitest unit tests and the repository integration suite.
Conventions:
- Validate external input at the route boundary.
- Keep database access behind repository modules.
- Add or update a regression test with every bug fix.
Avoid:
- Writing secrets, production data, or generated output into source files.
- Bypassing protected migrations or deployment approval.

set -euo pipefail
echo "=== Windsurf Architecture Check ==="
echo "Rules: $([ -f .devin/rules/project.md ] && wc -c < .devin/rules/project.md || echo 'MISSING') chars"
echo "Ignore: $([ -f .codeiumignore ] && wc -l < .codeiumignore || echo 'MISSING') patterns"
echo "Rules dir: $(ls .devin/rules/ 2>/dev/null | wc -l || echo 0) files"
echo "Workflows: $(ls .windsurf/workflows/ 2>/dev/null | wc -l || echo 0) files"