Genkit MCP

# Servers Starting a Genkit application or developer CLI spawns several server daemons as either independent processes, threads, goroutines, or coroutines, depending upon the runtime. The initialization process deals with: * **Environment-based startup**: In development mode (`GENKIT_ENV=dev`), the Reflection server starts automatically. * **Port selection**: All servers attempt to find available ports, with configurable defaults. * **Registration**: Each server registers itself for cleanup on application exit. * **Runtime files**: Reflection servers write metadata files to enable tool discovery (`<working-directory>/.genkit/runtimes/<timestamp>.json`). * **Traces**: Traces metadata (`<working-directory>/.genkit/traces`). ## Types | Server Type | Purpose | Implementation | Notes | |---------------------------|-----------------------------------------------------------------------|-------------------------------------------|---------------------------------------------------------| | Reflection | Development-time API for inspecting and interacting with Genkit | Both Go and JavaScript | Only starts in development mode (`GENKIT_ENV=dev`) | | Flow | Exposes registered flows as HTTP endpoints | Go (HTTP server) and JavaScript (Express) | Main server for production environment | | Dev UI | Web interface for monitoring and interacting with Genkit applications | JavaScript only | Provides dashboard, monitoring, and debugging tools | | Telemetry | Collects and stores traces of Genkit operations | JavaScript only | Can use local file system or Firestore as backing store | | Engineering documentation | `mkdocs` instances showing this information | | Engineering documentation | ## Networking | Server | Host | Port | Deployment Environment | |---------------------------|-------------|------------------------------------------|------------------------| | Flows | `localhost` | 3400 (override `PORT`) | `'dev'`, `'prod'` | | Dev UI/Tools API | `localhost` | 4000-4099 | `'dev'`, `'prod'` | | Reflection API | `localhost` | 3100 (override `GENKIT_REFLECTION_PORT`) | `'dev'` | | Telemetry | `localhost` | 4033 (specified programmatically) | `'dev'`, `'prod'` | | Engineering documentation | `localhost` | 8000 | `'dev'` | ## Implementations | Server | Sources | |------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | Flows | [JS](https://github.com/firebase/genkit/blob/main/js/plugins/express/src/index.ts), [Go](TODO), [Python](TODO) | | Telemetry | [JS](https://github.com/firebase/genkit/blob/main/genkit-tools/telemetry-server/src/index.ts) | | Dev UI/Tools API | [JS](https://github.com/firebase/genkit/blob/main/genkit-tools/common/src/server/server.ts) | | Reflection | [JS](https://github.com/firebase/genkit/blob/main/js/core/src/reflection.ts), [Go](https://github.com/firebase/genkit/blob/main/go/genkit/reflection.go), [Python](TODO) | ## Environment Variables | Environment Variable | Server/Component | Default Value | Description | |--------------------------------|---------------------------------|---------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------| | `DEBUG` | Logger | `false` | Sets the logging level to `'debug'` instead of `'info'`. | | `FIREBASE_CONFIG` | Firebase plugins | - | JSON configuration for Firebase services. | | `FIREBASE_DEBUG_FEATURES` | Firebase plugins | - | List of Firebase features to enable debugging for. | | `FIREBASE_DEBUG_MODE` | Firebase plugins | `false` | Enables debug mode for Firebase plugins. | | `FIREBASE_PROJECT_ID` | Firebase plugins | - | Project ID for Firebase services. | | `FIRESTORE_COLLECTION` | Firebase Firestore | - | Name of Firestore collection to use. | | `GCLOUD_LOCATION` | Vertex AI | - | Location for Vertex AI services. | | `GCLOUD_PROJECT` | Google Cloud plugins | - | Project ID for Google Cloud services. | | `GCLOUD_SERVICE_ACCOUNT_CREDS` | Google Cloud plugins | - | JSON credentials for authenticating with Google Cloud. | | `GENKIT_ENV` | All servers | `'prod'` | Controls the environment mode. Values: `'dev'` (development) or `'prod'` (production). In `'dev'` mode, additional servers are started such as the Reflection server. | | `GENKIT_GA_DEBUG` | Analytics | `false` | Enables debug mode for Google Analytics in the dev tools. | | `GENKIT_GA_VALIDATE` | Analytics | `false` | Enables validation mode for Google Analytics in the dev tools. | | `GENKIT_REFLECTION_PORT` | Reflection Server | 3100 | The port on which the Reflection API server listens in development mode. | | `GENKIT_RUNTIME_ID` | Reflection Server | Process ID | Custom identifier for the runtime (see `.genkit/runtimes/<timestamp>.json`). | | `GENKIT_TELEMETRY_SERVER` | Telemetry Client (Go/JS/Python) | - | URL of the telemetry server to send trace data to. | | `GOOGLE_API_KEY` | Google APIs | - | General API key for Google services, used as fallback. | | `GOOGLE_CLOUD_PROJECT` | Google Cloud plugins | - | Alternative name for Project ID for Google Cloud services. | | `GOOGLE_GENAI_API_KEY` | Google Generative AI | - | API key for Google's generative AI services. | | `PINECONE_API_KEY` | Pinecone plugin | - | API key for authenticating with Pinecone vector database. | | `PORT` | Flow Server | 3400 | The port on which the HTTP Flow server listens. | | `WEAVIATE_API_KEY` | Weaviate plugin | - | API key for authenticating with Weaviate. | | `WEAVIATE_URL` | Weaviate plugin | - | URL for the Weaviate vector database. | ## Signal Handling Many of these servers handle signals to handle graceful termination and clean up. | Signal | Handling | Handlers | |-----------|-----------------------------------|----------------------| | `SIGTERM` | Graceful termination | All servers | | `SIGINT` | Graceful termination and clean up | main Genkit instance | !!! note annotate "Common Signals" | Signal | Number | Description | Default Action | Notes | |----------------------|----------|---------------------------------------------------------------------------------------------------------|-----------------------|-----------------------------------------------------------------| | `SIGHUP` | 1 | Hangup signal. Sent when the controlling terminal closes or a process is terminated. | Terminate | Often used to tell daemons to reload their configuration files. | | `SIGINT` | 2 | Interrupt signal. Sent when the user presses `Ctrl+C`. | Terminate | Typically used to interrupt a running program. | | `SIGQUIT` | 3 | Quit signal. Sent when the user presses `Ctrl+\\`. | Terminate (core dump) | Similar to SIGINT, but also generates a core dump. | | `SIGILL` | 4 | Illegal instruction. Sent when a process attempts to execute an invalid instruction. | Terminate (core dump) | Indicates a programming error. | | `SIGTRAP` | 5 | Trace/breakpoint trap. Sent when a breakpoint is hit during debugging. | Terminate (core dump) | Used by debuggers. | | `SIGABRT` (`SIGIOT`) | 6 | Abort signal. Sent when a process calls the `abort()` function. | Terminate (core dump) | Indicates an abnormal termination. | | `SIGBUS` | 7 or 10 | Bus error. Sent when a process attempts to access memory that is not properly aligned. | Terminate (core dump) | Indicates a hardware or memory error. | | `SIGFPE` | 8 | Floating-point exception. Sent when a process performs an invalid arithmetic operation. | Terminate (core dump) | Indicates an arithmetic error. | | `SIGKILL` | 9 | Kill signal. Forces a process to terminate immediately. | Terminate | Cannot be caught or ignored. | | `SIGUSR1` | 10 or 30 | User-defined signal 1. | Terminate | Can be used for custom signal handling. | | `SIGSEGV` | 11 | Segmentation violation. Sent when a process attempts to access memory that it is not allowed to access. | Terminate (core dump) | Indicates a memory access error. | | `SIGUSR2` | 12 or 31 | User-defined signal 2. | Terminate | Can be used for custom signal handling. | | `SIGPIPE` | 13 | Pipe broken. Sent when a process attempts to write to a pipe that has no readers. | Terminate | Indicates a communication error. | | `SIGALRM` | 14 | Alarm clock. Sent when a timer expires. | Terminate | Used for timeouts. | | `SIGTERM` | 15 | Termination signal. Sent by the `kill` command by default. | Terminate | Allows a process to perform cleanup before exiting. | | `SIGCHLD` | 17 or 20 | Child process status changed. Sent to a parent process when a child process terminates or stops. | Ignore | Used for process management. | | `SIGCONT` | 18 or 19 | Continue signal. Sent to a stopped process to resume execution. | Continue | Used for job control. | | `SIGSTOP` | 19 or 17 | Stop signal. Forces a process to stop execution. | Stop | Cannot be caught or ignored. | | `SIGTSTP` | 20 or 18 | Terminal stop signal. Sent when the user presses `Ctrl+Z`. | Stop | Used for job control. | | `SIGTTIN` | 21 | Terminal input. Sent to a background process that attempts to read from the terminal. | Stop | Used for job control. | | `SIGTTOU` | 22 | Terminal output. Sent to a background process that attempts to write to the terminal. | Stop | Used for job control. |