@copilotkit/channels-core

The supported platform-neutral foundation behind @copilotkit/channels. Most applications should use the batteries-included @copilotkit/channels package; install core directly when building an adapter or intentionally selecting one platform.

Selective install

pnpm add @copilotkit/channels-core @copilotkit/channels-slack

{
  "compilerOptions": {
    "jsx": "react-jsx",
    "jsxImportSource": "@copilotkit/channels-core"
  }
}

import { createChannel } from "@copilotkit/channels-core";
import { slack } from "@copilotkit/channels-slack";

createChannel(opts) returns a Channel:

• onMention(handler) / onMessage(handler) — turn handlers receiving { thread, message }. (Routing is mention-preferred: if any mention handler is registered, all turns route to it; otherwise message handlers fire.)
• onThreadStarted(handler) — a conversation surface opened (e.g. the Slack assistant pane); receives { thread, user? }. Greet, set suggested prompts or a title, or run the agent. Adapters without the concept never fire it.
• onInteraction<TValue>(id, handler) — explicit escape-hatch handler for a known action id, bypassing the registry; ctx.action.value is typed TValue.
• onInterrupt<TPayload>(eventName, handler) — handle a captured agent interrupt (LangGraph-style on_interrupt); receives { payload, thread } with payload typed TPayload.
• onCommand(command) / onCommand(name, handler) — register a slash command. The handler gets { thread, command, text, options, user }. text is the raw args (Slack); options is the typed, parsed form (defineChannelCommand with an options Standard Schema) for surfaces with native structured args (e.g. Discord). Forwarded to adapters that support commands and ignored elsewhere — also pass them up front via commands in CreateChannelOptions.
• tool(t) — register a ChannelTool (alternative to opts.tools); must be added before start().
• start() / stop() — bring adapters up / down.

agent is optional. If omitted, calling thread.runAgent() throws; supply an AbstractAgent or a (threadId) => AbstractAgent factory.

Thread

A Thread is the per-conversation handle handed to your handlers and tool contexts. It accepts any Renderable (JSX or a string) for posting.

interface Thread {
  readonly platform: string;
  post(ui: Renderable): Promise<MessageRef>;
  update(ref: MessageRef, ui: Renderable): Promise<MessageRef>;
  delete(ref: MessageRef): Promise<void>;
  stream(src: string | AsyncIterable<string>): Promise<MessageRef>;
  runAgent(input?: {
    context?: ContextEntry[];
    tools?: ChannelTool[];
  }): Promise<MessageRef | undefined>;
  resume(value: unknown): Promise<MessageRef | undefined>;
  awaitChoice<T = unknown>(ui: Renderable): Promise<T>;
  // Capability-gated (return { ok: false } on surfaces without support):
  setSuggestedPrompts(
    prompts: ReadonlyArray<{ title: string; message: string }>,
    opts?: { title?: string },
  ): Promise<{ ok: boolean; error?: string }>;
  setTitle(title: string): Promise<{ ok: boolean; error?: string }>;
}

• post / update render the JSX to IR, bind every event-prop handler in the tree (mint a content-stable id, snapshot it, rewrite the prop to { id }), then hand the IR to the adapter.
• runAgent resolves the conversation's agent session, creates the adapter's RunRenderer, and drives the run/tool/interrupt loop. Per-run tools / context are merged on top of the channel-level defaults for that run only.
• resume(value) re-enters a paused interrupt run with forwardedProps.command.
• awaitChoice<T>(ui) posts a picker and blocks until an interaction in this conversation resolves it to the clicked control's value (HITL); pass T to type the returned value.

Tools & context

A ChannelTool is forwarded to the agent as a frontend tool; its handler runs in the channel when the agent calls it. The handler ctx carries the thread, so a tool can render JSX (ctx.thread.post(<Card .../>)) or run the agent further.

interface ChannelTool<Schema extends ObjectSchema = ObjectSchema> {
  name: string;
  description: string;
  parameters: Schema; // any Standard Schema (Zod/Valibot/ArkType/…)
  handler(args, ctx: ChannelToolContext): Promise<unknown> | unknown;
}

Define one with the non-curried defineChannelTool, which infers the arg types from parameters:

defineChannelTool({
  name: "read_thread",
  description: "Read the messages in the current conversation.",
  parameters: z.object({}),
  async handler(_args, { thread }) {
    return await thread.getMessages();
  },
});

parameters (a Standard Schema) is converted to JSON Schema for the LLM and validated on the way back. ChannelToolContext is { thread, message?, user?, signal?, platform } — a single shared type with no per-adapter generic. Platform-specific power is reached only through capability-gated thread methods (e.g. thread.getMessages(), thread.lookupUser(query), thread.postFile(...)), so a tool stays portable across surfaces.

A ContextEntry is { description: string; value: string } — knowledge folded into the agent's system context on each runAgent.

ActionStore

Inline JSX handlers are bound by content. Each interactive node gets a content-stable, opaque minted id — mintId(componentName, path, props) = "ck:" + sha1(name | path | stableStringify(props)).slice(0,16). Only the opaque id (plus any small bind() args) is stamped on the native token; no props, PII, or secrets go over the wire.

On a click, the ActionRegistry resolves the handler from a hot in-memory cache; on a miss it rehydrates by loading the snapshot from the ActionStore, re-rendering the named component with the frozen props, and re-walking to the handler's path.

The default ActionStore is InMemoryActionStore (a Map with optional TTL). It is lost on restart: after a restart an old button click degrades to an ActionExpiredError ("this action expired"), which createChannel swallows. Durable actions require an external store (Redis / DB) — not shipped in v1. Implement the ActionStore interface (put / get / delete) and pass it as actionStore to make actions survive restarts.

Writing a PlatformAdapter

To target a new surface, implement PlatformAdapter from this package. The engine drives ingress through the IngressSink you receive in start(sink) (sink.onTurn(IncomingTurn) / sink.onInteraction(InteractionEvent) / sink.onCommand(IncomingCommand) / sink.onThreadStarted(IncomingThreadStart)) and egress through your post / update / stream / delete (which receive ChannelNode[] to translate to a native payload via render). You also provide createRunRenderer(target) (an AG-UI RunRenderer: the subscriber to stream into, plus accessors for captured tool calls and interrupts that the run-loop reads after each runAgent), decodeInteraction(raw) (native event → opaque InteractionEvent), lookupUser, a conversationStore (getOrCreate → AgentSession), and the surface capabilities / ackDeadlineMs. Optional capability methods like getMessages(target) and postFile(target, args) back the matching thread methods when the surface supports them — likewise setSuggestedPrompts(target, prompts, opts?) and setThreadTitle(target, title) back thread.setSuggestedPrompts / thread.setTitle, and sink.onThreadStarted(...) emits the "conversation opened" lifecycle event. Slash commands are also capability-gated: an adapter forwards invocations via sink.onCommand(IncomingCommand), and may implement registerCommands(specs) to publish the channel's declared commands up front (e.g. Discord's application-command API); adapters that omit it are skipped. See @copilotkit/channels-slack for a complete implementation.

Exports

createChannel, Channel, CreateChannelOptions, ChannelHandler, ThreadStartHandler; Thread; the PlatformAdapter boundary types (RunRenderer, IngressSink, IncomingTurn, InteractionEvent, IncomingCommand, IncomingThreadStart, SurfaceCapabilities, ReplyTarget, ConversationStore, AgentSession, CapturedToolCall, CapturedInterrupt, UserQuery); ActionStore / InMemoryActionStore / ActionSnapshot / ActionRegistry / ActionExpiredError; ChannelTool / ChannelToolContext / defineChannelTool / ChannelCommand / CommandContext / CommandSpec / defineChannelCommand / ContextEntry / AgentToolDescriptor / ObjectSchema and the tool helpers (toAgentToolDescriptors, parseToolArgs, stringifyHandlerResult); mintId / stableStringify; runAgentLoop; plus the re-exported @copilotkit/channels-ui vocabulary.