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open-multi-agent/packages/core


Open Multi-Agent


Open Multi-Agent

Describe the goal, not the graph.
Multi-agent orchestration that runs in your own environment.

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OMA Run Viewer replaying a real multi-agent run: task DAG and span waterfall views with per-task status, assignee, tokens, and tool calls


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@open-multi-agent/core is the OMA orchestration runtime for TypeScript backends. Give it one agent, an explicit task graph, or a dynamic workflow that the coordinator generates from a goal at runtime.

The runtime schedules dependencies, runs independent work in parallel, shares context across agents, and returns an inspectable result. For product positioning and known users, see the project overview.

Contents

Quick Start · Execution Modes · Scheduling · Capabilities · Architecture · Examples · Providers · Production · Documentation

Quick Start

Requires Node.js 20 or newer. For production, use a currently maintained Node.js LTS release. Scaffold and run a starter in one command:

npm create oma-app@latest my-oma

In an interactive terminal, the scaffolder selects a starter and Cloud/Ollama runtime, installs dependencies, then runs a deterministic demo and produces an offline dashboard. The demo uses scripted model responses, needs no API key, and makes no model request; OMA orchestration still runs locally for real. Pass --no-install to generate files only, or --no-run to install without starting the demo.

To add OMA to an existing backend:

npm install @open-multi-agent/core

Migrating from @jackchen_me/open-multi-agent? That package is deprecated; install @open-multi-agent/core instead.

import { OpenMultiAgent, type AgentConfig } from '@open-multi-agent/core'

const model = process.env.OMA_MODEL ?? 'gpt-5.4'

const agents: AgentConfig[] = [
  { name: 'researcher', model, systemPrompt: 'Find the relevant facts.' },
  { name: 'analyst', model, systemPrompt: 'Compare evidence and identify tradeoffs.' },
]

const orchestrator = new OpenMultiAgent({
  defaultProvider: 'openai',
  defaultModel: model,
})

const team = orchestrator.createTeam('research-team', {
  name: 'research-team',
  agents,
  sharedMemory: true,
})

const result = await orchestrator.runTeam(team, 'Compare three approaches and recommend one.')
console.log(result.agentResults.get('coordinator')?.output)

Set OPENAI_API_KEY for this example. For other hosted or local models, see Providers.

Execution Modes

Mode Method When to use Example
Single agent runAgent() One agent, one prompt basics/single-agent
Auto-orchestrated team runTeam() Give a goal, let the coordinator plan and execute basics/team-collaboration
Explicit pipeline runTasks() You define the task graph and assignments basics/task-pipeline

Use planOnly to inspect a generated task graph before execution, then createPlanArtifact() and runFromPlan() to replay it. runConsensus() adds a proposer→judge verification loop when one answer needs extra scrutiny.

Structured single-agent input

Agent.run(), Agent.stream(), and OpenMultiAgent.runAgent() keep the string form above and also accept a complete LLMMessage[]. Use the message form for caller-owned conversation history or blocks such as base64 images:

import { OpenMultiAgent, type LLMMessage } from '@open-multi-agent/core'

const messages: LLMMessage[] = [{
  role: 'user',
  content: [
    { type: 'text', text: 'Describe this image.' },
    {
      type: 'image',
      source: { type: 'base64', media_type: 'image/png', data: imageBase64 },
    },
  ],
}]

const result = await new OpenMultiAgent().runAgent(
  { name: 'vision', model: 'claude-sonnet-4-6' },
  messages,
)

For a persistent Agent.prompt() conversation, pass a string or one ContentBlock[] user turn; restore earlier turns through AgentConfig.history. Structured input is validated and defensively copied. beforeRun receives both the complete messages and its backwards-compatible latest-user prompt view. Process and ACP backends remain string-only and reject structured arguments instead of discarding history or images. See Structured Agent Input for copy, hook, progress/evaluation, and external-backend semantics, or run basics/structured-input.

Automatic runTeam() uses the deterministic router by default: no extra model call is made. Opt into Hybrid Semantic Routing with executionRouting: { strategy: 'hybrid' }; it keeps deterministic Team decisions and sends only Single candidates to a one-call, no-tool TaskProfiler. Deterministic policy may keep Single, upgrade to Team, or require an explicit governance declaration. Valid custom executionRouter decisions, explicit mode, and declared governance retain higher priority. Auto results expose routingDecision and, when profiling ran, semanticRoutingAssessment. See Execution Routing. Execution Routing selects Single versus Team; Model Routing selects models inside that topology.

When Hybrid is enabled, the Profiler sends the goal to the configured routing adapter, then the Coordinator adapter, or finally the orchestrator's default provider. That last fallback can make a provider call even when every worker has its own adapter. Configure executionRouting.adapter or use deterministic strategy when the goal must not cross that provider boundary.

When an application must enforce named independent roles, declare that governance intent instead of relying on wording in the goal:

const governed = await orchestrator.runTeam(team, 'Review the evidence and assess the risk.', {
  governanceIntent: 'required',
  requiredRoles: ['researcher', 'analyst'],
  requiredOrder: ['researcher', 'analyst'],
})

if (governed.governanceConclusion !== 'satisfied') {
  throw new Error('Required governance was not satisfied by the executed topology.')
}

required and preferred both bypass automatic decomposition and the simple-goal short circuit. OMA creates one task per declared roster name, assigns it to that agent, and chains tasks in requiredOrder; dependency outputs are passed to downstream roles. The topology comes only from these structured fields, so equivalent goals in different languages use the same roles and order. none or an omitted governanceIntent preserves the existing automatic runTeam() behavior.

After execution, governanceConclusion is satisfied, unsatisfied, or not-applicable. Governance-sensitive applications must check it separately from success: the verdict comes from the structured execution receipt, not from role names or approval wording in the model answer. See Tool configuration.

Scheduling

Set schedulingStrategy on OpenMultiAgent to choose how unassigned tasks are mapped to agents. The setting applies to coordinator-generated runTeam() plans and explicit or restored task queues. Tasks with an explicit assignee keep that assignment.

Task DAG execution is event-driven: a downstream task starts as soon as its dependencies are satisfied, without waiting for unrelated tasks from the same ready set, and dependency outputs reach dependents as task-scoped results and validated structured handoffs.

const orchestrator = new OpenMultiAgent({
  schedulingStrategy: 'composite',
  schedulingWeights: { fit: 0.7, load: 0.3 },
})
Strategy Assignment behavior Recommended when
dependency-first (default) Assigns tasks that unblock the most downstream work first, rotating eligible agents The task graph has meaningful dependencies
round-robin Distributes tasks in queue order across eligible agents Agents are interchangeable
least-busy Chooses the eligible agent with the fewest active or newly assigned tasks Task duration varies and load balance matters
capability-match Filters explicit task requirements, then prefers declared capability tags before legacy keyword affinity Tasks or agents declare differentiated requirements/capabilities
composite Ranks tasks by blocked dependents, then maximizes fit and available capacity across eligible agents Criticality, capability fit, and current load should influence one decision

Agents may declare description, capabilities, costTier, and latencyClass, and tasks may add hard requires constraints. All strategies fail before worker execution when those constraints cannot be satisfied. Coordinator plans also fail fast by default when they name an agent outside the roster; set strictAssignees: false only to retain legacy reassignment. Weight semantics, load normalization, NO_ELIGIBLE_AGENT and INVALID_ASSIGNEE behavior, approval compatibility, and progress-event migration are covered in Task scheduling and dispatch.

Capabilities

Capability What you get
Dynamic orchestration Runtime goal decomposition, dependency-aware scheduling, parallel branches, configurable assignment, task-scoped results and handoffs, opt-in team context for workers (revealCoordinator), and final synthesis.
Models and reasoning Mix built-in, OpenAI-compatible, AI SDK, or local models; map one thinking config to each provider's reasoning setting, route phases separately, and preserve reasoning only when explicitly enabled.
Tools and handoffs Built-in tools are default-deny; custom tools, MCP, and guarded delegate_to_agent handoffs are opt-in, and consequential tools on undeclared runs are flagged for confirmation.
Controlled outputs Send text or structured single-agent input, stream per agent, validate results with Zod, approve or durably suspend plans, task rounds, dispatches, and tool calls, rewrite messages/prompts or post-process results with beforeRun / afterRun, and cancel with AbortSignal.
Evaluation Version EvalSets, run reference scorers, gate CI with offline reports, persist results, or sample production runs on a best-effort path.
Memory and recovery Shared memory is pluggable; checkpoints resume interrupted runs without repeating completed tasks.
Observability Stable run identity, traces, execution receipts, redaction, TraceStore, and the offline DAG/Waterfall Viewer are available without a hosted service.
External agents ACP and process backends let coding CLIs participate while OMA keeps scheduling, memory, and budgets.

Architecture

goal or explicit tasks
         |
         v
Coordinator -> Task DAG -> Scheduler -> AgentPool
                    |                       |-- LLM adapters
                    |                       `-- tools / external backends
                    |
                    |-- SharedMemory / checkpoints
                    |-- TraceRecord -> TraceStore / Run Viewer / OTel
                    `-- results -> evaluation (offline / sampled, observe-only)

The coordinator plans once by default; the scheduler owns execution order. Applications can opt into append-only adaptive recovery when task outcomes need to revise the unstarted part of the graph. Agents share results through memory, while checkpoints and traces form separate recovery and observability paths. Evaluation observes completed results and never changes them. Detailed contracts live in the linked subsystem guides below.

Examples

Start with one example that matches the behavior you need:

Goal Example
Send image blocks and caller-owned history basics/structured-input
See coordinator planning basics/team-collaboration
Build an explicit DAG cookbook/contract-review-dag
Observe event-driven DAG dispatch patterns/event-driven-dag
Validate structured output patterns/structured-output
Delegate between agents patterns/agent-handoff
Replay a frozen plan patterns/plan-replay
Suspend and resume an approval patterns/durable-approval
Embed OMA in a backend integrations/express-customer-support
Export an offline trace viewer integrations/observability-v2/run-viewer

The example index lists 50+ runnable examples across basics, cookbook workflows, patterns, providers, and integrations.

Providers

Change provider, model, and credentials; the agent shape stays the same.

Route Use
Built in Anthropic, OpenAI, Azure OpenAI, Copilot, Grok, DeepSeek, Doubao, Hunyuan, MiniMax, MiMo, Qiniu
Optional peers Gemini (@google/genai) and Bedrock (@aws-sdk/client-bedrock-runtime)
OpenAI-compatible Set provider: 'openai' + baseURL for Ollama, vLLM, LM Studio, OpenRouter, Groq, Mistral, Kimi, Qwen, or Zhipu
AI SDK Use AISdkAdapter with ai and your selected @ai-sdk/* provider (AI SDK 7 needs Node.js 22+)

Optional integrations load only when used: core directly installs only @anthropic-ai/sdk, openai, and zod; other SDKs are lazy-loading opt-in peers, and OpenTelemetry lives entirely in @open-multi-agent/otel. Dependency changes are weighed on demonstrated value plus security, size, maintenance, and compatibility cost, not a fixed count.

See Providers, framework-owned LLM egress policy, and Tool configuration for credentials, models, the AI SDK bridge, reasoning settings, MCP, local endpoints, and the exact network-enforcement boundary.

Production

Goal Configure
Bound work maxTurns, timeoutMs, callTimeoutMs, contextStrategy, loopDetection
Control spend maxTokenBudget; maxCostBudget + application-owned estimateCost
Limit tools tools / toolPreset, cwd / defaultCwd, tool-output caps
Recover Task retries, checkpointing, restore(), and opt-in adaptive plan repair
Review work planOnly, inline approval callbacks, or durable approval gates
Observe Trace sinks, TraceStore, execution receipts, Run Viewer, or the optional OTel adapter

Budget checks run at turn and task boundaries, so a run can overshoot by up to one model turn; they are not a cent-exact stop. estimateCost receives each call's token usage plus the agent, effective model, provider, phase, and taskId, and your application owns the price table.

Built-in tools are default-deny, and every model-visible tool result is sent to your model provider, so grant read and exec access deliberately. Tools may keep application-owned data separate while returning text, image, or file content through modelOutput; see the tool configuration guide. Filesystem tools stay within the configured cwd; granted bash is not sandboxed. Its execution target can be replaced through a ShellExecutor, while the default LocalShellExecutor preserves host execution and is not a security boundary. Secrets are redacted from traces, shell output, and Viewer payloads by default, but result messages and checkpoints have their own persistence boundary.

Observability

Core already provides run identity, trace sinks, execution receipts, queryable in-memory/file stores, and an offline Run Viewer. These cover local debugging, audit artifacts, and post-run analysis without OpenTelemetry.

@open-multi-agent/otel is an optional enterprise integration for teams that already operate a centralized OpenTelemetry stack. It converts OMA traces into standard OTel spans so multi-agent runs can join company-wide monitoring, alerting, and incident workflows. The application owns the provider and its lifecycle; telemetry failures never change the run result.

See the observability guide, migration guide, and performance guidance.

Documentation

Area Guides
Build agents Providers, structured input, tools, context
Run reliably Evaluation, checkpoint & resume, durable approvals, adaptive recovery, execution routing, model routing, consensus
Control workflows Plan preview & replay, shared memory, external agents
Operate Observability, CLI, production examples

Contributing

Issues and PRs are welcome. For production examples, follow the acceptance criteria; for code changes, see the contribution guide.

Contributors

Contributor credits by area

Framework features

  • @ibrahimkzmv (token budget, context strategy, dependency-scoped context, tool presets, glob, MCP integration, configurable coordinator, CLI, dashboard rendering, trace event types)
  • @apollo-mg (context compaction fix, sampling parameters)
  • @tizerluo (onPlanReady, onAgentStream)
  • @CodingBangboo (planOnly mode)
  • @Xin-Mai (output schema validation)
  • @JasonOA888 (AbortSignal support)
  • @EchoOfZion (coordinator skip for simple goals)
  • voidborne-d (OpenAI mixed-content fix, text-tool-extractor depth fix)
  • @NamelessNATM (agent delegation base implementation)
  • @MyPrototypeWhat (reasoning blocks, reasoning_effort, sampling parity, trace input/output)
  • @SiMinus (streaming reasoning events)
  • @matthewYang08 (OpenAI reasoning-to-text fallback)
  • @dvirarad (OpenAI-family adapter hardening)
  • @cat0825 (model routing policy, plan replay, structured shared-memory handoff)
  • @mvanhorn (checkpoint & resume)
  • @lesbass (run-level metrics rollup on TeamRunResult)
  • @tlysanhuo (trace span parent linkage)
  • @LambIessz (orchestrator cost budget, MessageBus persistence in checkpoints, retryable route fallback)
  • @Bobuyoucrypto (Windows bash timeout process-tree kill)

Provider integrations

Examples & cookbook

Docs & tests

License

MIT