✨ Feat: model capacity foundation — context management upgrade

AGENTS.md

@@ -8,7 +8,7 @@
 
 <!-- SKILLS_TABLE_START -->
 <usage>
-When users ask you to perform tasks, check if any of the available skills below can help complete the task more effectively. Skills provide specialized capabilities and domain knowledge.
+When users ask to perform tasks, check if any of the available skills below can help complete the task more effectively. Skills provide specialized capabilities and domain knowledge.
 
 How to use skills:
 - Invoke: `npx openskills read <skill-name>` (run in your shell)
@@ -40,3 +40,129 @@ Usage notes:
 <!-- SKILLS_TABLE_END -->
 
 </skills_system>
+
+---
+
+## Project Overview
+
+Nexent is a zero-code platform for auto-generating AI agents. Monorepo with:
+- `backend/` - FastAPI HTTP API
+- `sdk/nexent/` - Core agent framework (pip package)
+- `frontend/` - Next.js web UI
+- `docker/` & `k8s/` - Deployment configs
+
+---
+
+## Developer Commands
+
+### Backend (Python 3.10)
+
+```bash
+# Setup
+cd backend && uv sync --extra data-process --extra test
+
+# Install SDK for development
+cd backend && uv pip install -e "../sdk[dev]"
+```
+
+### Run Tests
+
+```bash
+# From project root, with backend venv activated
+source backend/.venv/bin/activate && python test/run_all_test.py
+
+# Single test file
+pytest test/backend/apps/test_agent_app.py -v
+```
+
+### Frontend (Next.js)
+
+```bash
+cd frontend
+npm run dev          # Development server
+npm run check-all    # type-check + lint + format + build
+```
+
+### Docker Deployment
+
+```bash
+cd docker
+cp .env.example .env  # Fill required configs
+bash deploy.sh        # Interactive deployment
+```
+
+---
+
+## Architecture
+
+### Environment Variables
+
+**Single source of truth**: `backend/consts/const.py`
+
+- NO direct `os.getenv()` / `os.environ.get()` outside this file
+- SDK (`sdk/nexent/`) NEVER reads env vars - accepts config via parameters
+- Services read from `consts.const` and pass to SDK
+
+### Backend Layer Structure
+
+| Layer | Path | Responsibility |
+|-------|------|----------------|
+| Apps | `backend/apps/` | HTTP boundary: parse input, call services, map exceptions to HTTP |
+| Services | `backend/services/` | Business logic orchestration, raise domain exceptions |
+| Consts | `backend/consts/` | Env vars (`const.py`), exceptions (`exceptions.py`), error codes |
+
+**Exception flow**: Services raise domain exceptions → Apps map to HTTP status codes
+
+---
+
+## Database Migrations
+
+**Location**: `docker/sql/*.sql` (versioned migration scripts)
+
+**Critical rule**: When adding columns/tables via migration script:
+- Update `docker/init.sql` (Docker Compose fresh deploy)
+- Update `k8s/helm/nexent/charts/nexent-common/files/init.sql` (K8s fresh deploy)
+
+**Version**: Tracked in `backend/consts/const.py` as `APP_VERSION`
+
+---
+
+## Testing Conventions
+
+- pytest only (no unittest)
+- Mock at import site with fully-qualified path:
+  ```python
+  mocker.patch("backend.services.agent_service.AgentService.run", return_value={...})
+  ```
+- Async tests: `@pytest.mark.asyncio`
+- Test structure: `test/backend/` and `test/sdk/`
+
+---
+
+## Code Style
+
+- English-only comments and docstrings (enforced by `.cursor/rules/english_comments.mdc`)
+- Import order: stdlib → third-party → project
+- Line length: 119 (sdk ruff config)
+
+---
+
+## Key Files
+
+| File | Purpose |
+|------|---------|
+| `backend/consts/const.py` | All env var definitions, APP_VERSION |
+| `backend/consts/exceptions.py` | Domain exceptions (AgentRunException, LimitExceededError, etc.) |
+| `docker/init.sql` | Database schema for Docker Compose |
+| `k8s/helm/.../init.sql` | Database schema for Kubernetes |
+| `test/run_all_test.py` | Test runner with coverage |
+
+---
+
+## Reference Files
+
+Existing instruction files with detailed rules:
+- `CLAUDE.md` - Backend architecture, env var management, app/service layer rules
+- `.cursor/rules/environment_variable.mdc` - Env var centralization
+- `.cursor/rules/pytest_unit_test_rules.mdc` - Testing patterns
+- `.cursor/rules/english_comments.mdc` - Comment language enforcement