# Context Propagation Demo
Demonstrates how Genkit propagates context through the execution chain:
generate calls, flows, tools, and nested operations.
## Features Demonstrated
| Feature | Flow | Description |
|---------|------|-------------|
| Context in Generate | `context_in_generate` | Pass `context=` to `ai.generate()`, tool reads via `ctx.context` |
| Context in Flow | `context_in_flow` | Flow receives `ActionRunContext`, reads `ctx.context` |
| Static Context Access | `context_current_context` | Tool reads context via `Genkit.current_context()` |
| Context Propagation | `context_propagation_chain` | Context flows through nested generate/tool calls |
## ELI5: Key Concepts
| Concept | ELI5 |
|---------|------|
| **Context** | Extra info passed alongside the AI request — like a sticky note on a letter |
| **`ctx.context`** | Read the sticky note inside a tool or flow |
| **`Genkit.current_context()`** | Read the sticky note from anywhere — like a global bulletin board |
| **Propagation** | Context automatically passes through nested calls — like a family name |
## Quick Start
```bash
export GEMINI_API_KEY=your-api-key
./run.sh
```
Then open the Dev UI at http://localhost:4000.
## Flows
| Flow | What It Demonstrates |
|------|---------------------|
| `context_in_generate` | Pass `context=` to `ai.generate()`, tool reads via `ctx.context` |
| `context_in_flow` | Flow receives `ActionRunContext`, reads `ctx.context` |
| `context_current_context` | Tool reads context via static `Genkit.current_context()` |
| `context_propagation_chain` | Context flows: flow -> generate -> tool -> nested generate -> nested tool |
## Testing Checklist
- [ ] `context_in_generate` -- Returns user-specific data based on `user_id` in context
- [ ] `context_in_flow` -- Shows context is accessible inside the flow itself
- [ ] `context_current_context` -- Shows `Genkit.current_context()` works from anywhere
- [ ] `context_propagation_chain` -- Verifies context survives multi-level nesting
## How Context Works
```
ai.generate(context={'user': {'id': 42}})
|
v
ContextVar set with {'user': {'id': 42}}
|
+----> Tool reads ctx.context['user']['id']
|
+----> Genkit.current_context() reads same ContextVar
|
+----> Nested ai.generate() inherits context automatically
```
## Development
The `run.sh` script uses `watchmedo` for hot reloading on file changes.
