Mastra is a TypeScript framework for building and shipping AI agents, focusing on rapid prototyping and production readiness. It provides a structured approach for defining agents, tools, and integrating with various LLM providers through a unified model router. The framework includes a Studio UI for managing development workflows and supports integration into existing web frameworks.

SmolAgents is a lightweight Python library designed for building and running AI agents with minimal code. It offers first-class support for 'Code Agents' that execute Python, along with standard tool-calling agents. The framework is highly model, modality, and tool-agnostic, providing great flexibility for integration.

• +Provides a structured TypeScript framework for building AI agents, enabling fast prototyping and reliable deployment.
• +Offers an integrated model router that abstracts LLM providers (OpenAI, Anthropic, Google, xAI) using a `provider/model` string format and environment variables.
• +Enforces a clear structure for defining tools via `createTool()` including Zod schemas for input/output, preventing silent execution failures.
• +Includes Mastra Studio, an interactive UI for building, testing, and managing agents, workflows, and tools.
• +Supports integration with popular web frameworks like Next.js, React, Astro, Express, SvelteKit, and Hono.
• +Enables a wide range of use cases, including customer-facing assistants, internal copilots, data analysis, content automation, and DevOps.
• +Provides access to a large selection of models through its model router, beyond a short list of known IDs.

• +Extremely simple, with agent logic abstracted minimally, making it easy to learn and use.
• +First-class support for Code Agents executing Python actions in sandboxed environments for secure, composable logic.
• +Supports common JSON/text-based Tool-Calling Agents for alternative paradigms.
• +Model-agnostic, integrating easily with Hugging Face Inference, OpenAI, Anthropic, LiteLLM, Transformers, and Ollama.
• +Modality-agnostic, capable of handling vision, video, and audio inputs.
• +Tool-agnostic, allowing integration of tools from MCP servers, LangChain, or Hugging Face Spaces.
• +Includes CLI tools for quickly running agents without boilerplate code.

• −Plain object tool definitions silently fail to execute; tools must be strictly defined via `createTool()` with specific properties.
• −Requires a `package.json` file with `"type": "module"` for project setup.
• −Requires Node.js 22.18.0 or later for direct TypeScript file execution.

• −Lacks explicit built-in state management for persistent agent memory or conversational context.
• −Relies on external services (Modal, Blaxel, E2B, Docker) for secure code execution sandboxing.

Mastra manages state through explicitly defined Agent and Tool objects, configured within a central Mastra instance, which then handles model routing and execution context via environment variables.

The framework does not provide an explicit built-in state management system; state must be managed via agent code or external mechanisms.