Introducing Claude Code, Cursor, and Codex agents in Mastra

Mastra is now an agent meta-harness. Starting today, you can run Claude Code, Cursor, and Codex subagents from within Mastra.

Subagents inherit Mastra’s stream composition APIs — hand off to a workflow, or vice versa. You can write evals for them, chat with them in Studio, and swap one for another without changing your code.

Mastra has always been model-agnostic. Today with so many harnesses, we’re taking a step towards being harness agnostic as well.

Harnesses maintain their existing feature set — file handling, codebase reasoning, multi-agent handoffs, permission controls — and inherit Mastra’s agent surface:

• Calls: .generate(), .stream(), .resumeGenerate(), .resumeStream()
• Per-run options: requestContext, abortSignal, instructions, structuredOutput, runId, tracingContext
• Composition: workflow steps, subagent delegation, attached tools
• Observability: logs, traces, token usage, model cost in Studio