Mastra is a TypeScript agent framework from the team behind Gatsby. It is the batteries-included TypeScript option: agents, workflows, memory, evals, and a local dev playground in one framework. It is built on top of the Vercel AI SDK, which is how it reaches more than forty model providers through one interface, so it is fully model-agnostic. Its license is mostly Apache-2.0, with a wrinkle: code in directories named ee/ is source-available under a separate Mastra Enterprise License and needs a paid seat-based license for production use. Multi-agent work uses a supervisor pattern, where one agent coordinates sub-agents exposed to it as tools. MCP support is native in both directions (consuming servers and exposing Mastra tools as a server). Mastra reached 1.0 in January 2026. For open-source AI, Mastra and the Vercel AI SDK are the two TypeScript-native picks in a field that is otherwise Python-first. The core is open; the enterprise carve-out is narrow but worth knowing about before building on the ee/ pieces.
The Stack · Agents · Open source
Mastra
Independent TypeScript agent framework from the Gatsby team; Apache-2.0 core (separate enterprise license for ee/ directories), built on the Vercel AI SDK, native MCP, supervisor/sub-agents. 1.0 released January 2026.
Sources
- Mastra agents documentation https://mastra.ai/en/docs/agents/overview
- Mastra LICENSE (Apache 2.0 core plus ee/ carve-out) https://raw.githubusercontent.com/mastra-ai/mastra/main/LICENSE.md
- Mastra Enterprise License (ee/) https://raw.githubusercontent.com/mastra-ai/mastra/main/ee/LICENSE
- Mastra MCP overview https://mastra.ai/docs/mcp/overview
- Announcing Mastra 1.0 (2026-01-20) https://mastra.ai/blog/announcing-mastra-1
Want a follow-up? Ask the chat about Mastra in context. It will compare to siblings at the same layer and ground every claim in the wiki.
Other projects at the Agents layer
19 siblings · ordered open first
- Goose (Block) Open source
Block's open agent; under the Linux Foundation's AAIF since Dec 2025; MCP-native; BYOK; extension-based.
- OpenHands Open source
Formerly OpenDevin; sandboxed open coding agent; strong SWE-bench Verified performance.
- Aider Open source
Paul Gauthier's terminal-native open coding agent; BYOK; git-aware diffs; widely loved for its directness.
- Cline Open source
VS Code-native open coding agent; large community of users; began as Claude Dev.
- Continue Open source
Open IDE coding agent for VS Code and JetBrains; broader IDE integration than most.
- LangChain Open source
Most-used open agent framework; LLM tools, chains, RAG primitives, and LangGraph for low-level agent orchestration. MCP via the langchain-mcp-adapters package.
- LlamaIndex Open source
Open framework for data-aware LLM applications; strong on RAG, now also an agent framework via AgentWorkflow. MCP via the llama-index-tools-mcp package.
- AutoGen Open source
Microsoft's multi-agent conversation framework, now maintenance-mode; consolidated with Semantic Kernel into the Microsoft Agent Framework (1.0 GA April 2026).
- OpenAI Agents SDK Open source
OpenAI's lightweight agent SDK and the production successor to Swarm; MIT, Python and TypeScript, provider-agnostic via LiteLLM, handoffs, native MCP.
- Claude Agent SDK Open source
Anthropic's agent SDK extracted from Claude Code; the package is MIT but its use is governed by Anthropic's Commercial Terms, and it is Claude-only. Native plus in-process MCP, subagents. Renamed from the Claude Code SDK September 2025.
- Google ADK (Agent Development Kit) Open source
Google's open agent framework; Apache-2.0, multi-language (Python, Java, Go, TypeScript, Kotlin), Gemini-optimized but model-agnostic, native bidirectional MCP. 2.0 GA May 2026.
- Vercel AI SDK Open source
Vercel's TypeScript AI toolkit; Apache-2.0, model-agnostic via a unified provider API, subagents, native MCP. AI SDK 6 GA December 2025.
- Strands Agents Open source
AWS's open agent SDK; Apache-2.0, Python (TypeScript in preview), Bedrock-default but model-agnostic, native MCP, workflow/graph/swarm multi-agent. 1.0 GA July 2025.
- Microsoft Agent Framework Open source
Microsoft's open agent framework consolidating AutoGen and Semantic Kernel; MIT, Python and .NET, model-agnostic via connectors, native MCP and A2A, graph-based orchestration. 1.0 GA April 2026.
- Pydantic AI Open source
Pydantic's MIT agent framework; Python, model-agnostic, type-safe through Pydantic models, native MCP, A2A plus graph multi-agent. 1.0 released September 2025.
- CrewAI Open source
Independent MIT agent framework; Python, model-agnostic via LiteLLM, role-based "crews" for multi-agent work, MCP via the crewai-tools adapter. 1.0 GA October 2025.
- Claude Code (Anthropic) Proprietary
Anthropic's first-party CLI coding agent; closed-source; subscription model; the dominant closed coding agent in 2026.
- Cursor Proprietary
Closed VS-Code-fork IDE with integrated agentic features; strong developer adoption.
- Devin (Cognition Labs) Proprietary
Cognition's closed autonomous-software-engineer agent; was first to publicize SWE-bench scores.