@sapiom/agent

@sapiom/agent

The versioned public contract for authoring Sapiom orchestrations.

A lean, dependency-light package (types + a small protocol runtime) shared by three consumers:

• Customer orchestration definitions — authored against this package's types and compiled by the build.
• The sandbox step-runner — reads a step's input, builds ctx, runs one step.
• The engine — uses the directive guards + manifest schema; it never runs customer code, only validates the pure-data completion payload.

Install

npm install @sapiom/agent

Authoring surface

import {
  defineAgent,
  defineStep,
  goto,
  terminate,
} from "@sapiom/agent";

const start = defineStep({
  name: "start",
  next: ["finish"],
  async run(input, ctx) {
    return goto("finish", { greeting: `hello ${input.name}` });
  },
});

const finish = defineStep({
  name: "finish",
  next: [],
  terminal: true,
  async run() {
    return terminate({ done: true });
  },
});

export const hello = defineAgent({
  name: "hello",
  entry: "start",
  steps: { start, finish },
});

A step declares the transitions it may take (next / terminal / canFail / pause); the run return type is derived from those declarations, so an undeclared transition is a compile error. The build reads those same declarations to render the orchestration graph without executing anything.

Pausing on a long-running capability

Some ctx.sapiom capabilities are dispatched: you launch them, they run far past one step's budget, and they report back when they finish (a coding agent today; more below). A step can't inline-await one — it pauses, and a later step resumes with the result. pauseUntilSignal accepts the launch handle (or the launch promise itself) and reads everything it needs off it:

import { defineStep, pauseUntilSignal, terminate } from "@sapiom/agent";
import { CODING_RESULT_SIGNAL } from "@sapiom/tools";

const code = defineStep({
  name: "code",
  next: ["review"],
  // capability's exported signal constant so the decl can't drift from the handle.
  pause: { signal: CODING_RESULT_SIGNAL, resumeStep: "review" },
  async run(input, ctx) {
    // launch returns immediately; hand it straight to pauseUntilSignal. The run
    // parks at status='paused' and the dispatch loop exits.
    return pauseUntilSignal(
      ctx.sapiom.models.coding.launch({ task: input.task }),
      {
        resumeStep: "review",
      },
    );
  },
});

const review = defineStep({
  name: "review",
  next: [],
  terminal: true,
  // Give this step an `inputSchema` (a zod schema for the capability's result
  // shape) to type + validate what it receives.
  async run(result, ctx) {
    // Fires on success OR failure — branch on the terminal result.
    return terminate({ ok: result.status === "completed" });
  },
});

Things to know:

• The pause is a real suspend across processes, so the launch and the resume are two steps — you can't fold them into one inline await.

• The resumed step receives the capability's result as its input. Declare its inputSchema to type + validate it (each capability documents its result shape).

• Pass the launch promise directly for the one-liner above, or await it first when you need the handle — to stash the run id in ctx.shared, or to try/catch a launch failure and route somewhere other than a retry. Awaiting doesn't lose the pause; the resolved handle still flows into pauseUntilSignal:

  async run(input, ctx) {
    const run = await ctx.sapiom.models.coding.launch({ task: input.task });
    ctx.shared.set("codingRunId", run.runId); // readable from the resumed step
    return pauseUntilSignal(run, { resumeStep: "review" });
  }
  

• Outside a workflow nothing changes — await launch().wait() the capability as usual; the pause wiring only engages when a step pauses on the handle.

Compatible capabilities

Any capability whose launch returns a DispatchHandle (a dispatch member) is pausable; each ships a stable result-signal constant for the pause decl. This list grows as capabilities land:

Capability	Launch	Pause signal
Coding agent	ctx.sapiom.models.coding.launch(…)	CODING_RESULT_SIGNAL (@sapiom/tools)