@agentproto/adapter-mastracode-inprocess

Mastra Code driven in-process via its mastracode / mastracode/headless SDK, instead of spawning npx mastracode as a subprocess. Implements the AIP-45 protocol: "proprietary" arm contract directly — no child process, no argv, no JSONL pipe.

import { mastracodeInprocessRuntime } from "@agentproto/adapter-mastracode-inprocess"

const runtime = mastracodeInprocessRuntime()
const session = await runtime.start({ cwd: process.cwd() })

for await (const evt of session.send("Fix the failing test in src/foo.ts")) {
  console.log(evt)
}
await session.close()

// Resume later — same process or a fresh one — via the sessionId the
// first session returned:
const resumed = await runtime.start({ resumeSessionId: session.sessionId })

See @agentproto/driver-agent-cli's createAgentCliRuntime for the generic AgentCliRuntime/AgentCliClient contract this package implements.

How it works

manifest (src/index.ts, protocol: "proprietary")
        │ createAgentCliRuntime skips the subprocess spawn
        ▼
createProprietaryProtocolArm  ──dynamic import──▶  this package
        │                                                │
        │                              createAgentCliClient(definition)
        ▼                                                ▼
   AgentCliClient  ◀── src/client.ts ── createMastraCode() + runMC()
        │
        │ mapMastraEvent (reused from @agentproto/driver-agent-cli's print arm)
        ▼
    StreamEvent

Why this is a separate package from @agentproto/adapter-mastracode

That package spawns the CLI (protocol: "print") per turn; this one holds a live in-process AgentController across turns and never shells out. Different dependency surface, different process lifecycle, different session-id shape — see MASTRACODE-INPROCESS.md for the full rationale.

Session ids

sessionId is a composite "<resourceId>:<threadId>" string — an implementation detail of how Mastra Code resolves threads for a live AgentController, documented in full in MASTRACODE-INPROCESS.md. Hosts should treat it as an opaque string: persist whatever sessionId returns and pass it back as resumeSessionId to resume, including across a process restart.

Isolation

Storage and Mastra Code's global home-dir config discovery are both redirected to a dedicated location under $AGENTPROTO_HOME (default ~/.agentproto/mastracode-inprocess/), so this arm's sessions never collide with — or leak into — a developer's own interactive mastracode usage. See MASTRACODE-INPROCESS.md for specifics and a known limitation around homeDir propagation.

Modes and options

modes (plan / build / fast) and options (model / effort) are declared on the manifest; see MASTRACODE-INPROCESS.md for how they reach client.ts (env-carried mode selection, direct model/effort passthrough).

Spec

See AIP-45.