CLI Commands
You can use the Command-Line Interface (CLI) provided by Mastra to develop, build, and start your Mastra project.
mastra dev
Starts a server which exposes a local dev playground and REST endpoints for your agents, tools, and workflows. You can visit http://localhost:4111/swagger-ui for an overview of all available endpoints once mastra dev is running.
You can also configure the server.
Flags
The command accepts common flags and the following additional flags:
--https
Enable local HTTPS support. Learn more.
--inspect
Start the development server in inspect mode, helpful for debugging. This can't be used together with --inspect-brk.
--inspect-brk
Start the development server in inspect mode and break at the beginning of the script. This can't be used together with --inspect.
--custom-args
Comma-separated list of custom arguments to pass to the development server. You can pass arguments to the Node.js process, e.g. --experimental-transform-types.
Configs
You can set certain environment variables to modify the behavior of mastra dev.
Disable build caching
Set MASTRA_DEV_NO_CACHE=1 to force a full rebuild rather than using the cached assets under .mastra/:
MASTRA_DEV_NO_CACHE=1 mastra dev
This helps when you are debugging bundler plugins or suspect stale output.
Limit parallelism
MASTRA_CONCURRENCY caps how many expensive operations run in parallel (primarily build and evaluation steps). For example:
MASTRA_CONCURRENCY=4 mastra dev
Leave it unset to let the CLI pick a sensible default for the machine.
Custom provider endpoints
When using providers supported by the Vercel AI SDK you can redirect requests through proxies or internal gateways by setting a base URL. For OpenAI:
OPENAI_API_KEY=<your-api-key> \
OPENAI_BASE_URL=https://openrouter.example/v1 \
mastra dev
For Anthropic:
ANTHROPIC_API_KEY=<your-api-key> \
ANTHROPIC_BASE_URL=https://anthropic.internal \
mastra dev
These are forwarded by the AI SDK and work with any openai() or anthropic() calls.
mastra build
The mastra build command bundles your Mastra project into a production-ready Hono server. Hono is a lightweight, type-safe web framework that makes it easy to deploy Mastra agents as HTTP endpoints with middleware support.
Under the hood Mastra's Rollup server locates your Mastra entry file and bundles it to a production-ready Hono server. During that bundling it tree-shakes your code and generates source maps for debugging.
The output in .mastra can be deployed to any cloud server using mastra start.
If you're deploying to a serverless platform you need to install the correct deployer in order to receive the correct output in .mastra.
It accepts common flags.
Configs
You can set certain environment variables to modify the behavior of mastra build.
Limit parallelism
For CI or when running in resource constrained environments you can cap how many expensive tasks run at once by setting MASTRA_CONCURRENCY.
MASTRA_CONCURRENCY=2 mastra build
mastra start
You need to run mastra build before using mastra start.
Starts a local server to serve your built Mastra application in production mode. By default, OTEL Tracing is enabled.
Flags
The command accepts common flags and the following additional flags:
--dir
The path to your built Mastra output directory. Defaults to .mastra/output.
--no-telemetry
Disable the OTEL Tracing.
mastra lint
The mastra lint command validates the structure and code of your Mastra project to ensure it follows best practices and is error-free.
It accepts common flags.
mastra scorers
The mastra scorers command provides management capabilities for evaluation scorers that measure the quality, accuracy, and performance of AI-generated outputs.
Read the Scorers overview to learn more.
add
Add a new scorer to your project. You can use an interactive prompt:
mastra scorers add
Or provide a scorer name directly:
mastra scorers add answer-relevancy
Use the list command to get the correct ID.
list
List all available scorer templates. Use the ID for the add command.
mastra init
The mastra init command initializes Mastra in an existing project. Use this command to scaffold the necessary folders and configuration without generating a new project from scratch.
Flags
The command accepts the following additional flags:
--default
Creates files inside src using OpenAI. It also populates the src/mastra folders with example code.
--dir
The directory where Mastra files should be saved to. Defaults to src.
--components
Comma-separated list of components to add. For each component a new folder will be created. Defaults to ['agents', 'tools', 'workflows'].
--llm
Default model provider. Choose from: "openai" | "anthropic" | "groq" | "google" | "cerebras" | "mistral".
--llm-api-key
The API key for your chosen model provider. Will be written to an environment variables file (.env).
--example
If enabled, example code is written to the list of components (e.g. example agent code).
--no-example
Do not include example code. Useful when using the --default flag.
--mcp
Configure your code editor with Mastra's MCP server. Choose from: "cursor" | "cursor-global" | "windsurf" | "vscode".
Common flags
--dir
Available in: dev, build, lint
The path to your Mastra folder. Defaults to src/mastra.
--env
Available in: dev, build, start
Custom environment variables file to include. By default, includes .env.development, .env.local, and .env.
--root
Available in: dev, build, lint
Path to your root folder. Defaults to process.cwd().
--tools
Available in: dev, build, lint
Comma-separated list of tool paths to include. Defaults to src/mastra/tools.
Global flags
Use these flags to get information about the mastra CLI.
--version
Prints the Mastra CLI version and exits.
--help
Prints help message and exits.
Telemetry
By default, Mastra collects anonymous information about your project like your OS, Mastra version or Node.js version. You can read the source code to check what's collected.
You can opt out of the CLI analytics by setting an environment variable:
MASTRA_TELEMETRY_DISABLED=1
You can also set this while using other mastra commands:
MASTRA_TELEMETRY_DISABLED=1 mastra dev