Is subagent streaming supported in the JS version of deepagents? If so, what's the correct configuration? The Python docs show this is possible, but I can't find equivalent functionality in the JS implementation. #284
Description
Checked other resources
- This is a bug, not a usage question.
- I added a clear and descriptive title.
- I searched existing issues and didn't find this.
- I can reproduce this with the latest released version.
- I included a minimal reproducible example and steps to reproduce.
Area (Required)
- deepagents (SDK)
- cli
Related Issues / PRs
No response
Reproduction Steps / Example Code (Python)
// StreamProvider.jsx
const streamValue = useStream({
apiUrl: "http://localhost:5007",
apiKey: token,
assistantId: "widget-chat",
threadId: threadId,
filterSubagentMessages: true,
streamSubgraphs: true,
});
// Submit options
stream.submit(
{ messages: [...] },
{ streamSubgraphs: true, streamMode: ["values", "messages"] }
);
backend
import { createDeepAgent } from "deepagents";
const agent = createDeepAgent({
model: llm,
tools: [...],
subagents: [
{
name: "CEO Finder",
description: "Find CEO information",
systemPrompt: "...",
tools: [...],
},
// ...more subagents
],
});Error Message and Stack Trace (if applicable)
Description
When using deepagents (JS/TypeScript) with @langchain/langgraph-sdk's useStream hook, the stream.subagents Map and stream.activeSubagents array are always empty, even though the task tool is successfully spawning and running subagents.
Environment
deepagents: 1.8.1@langchain/langgraph-sdk: 1.6.5@langchain/langgraph-api: 1.1.14- Node.js: 20.x
- Platform: Windows
Frontend Configuration
// StreamProvider.jsx
const streamValue = useStream({
apiUrl: "http://localhost:5007",
apiKey: token,
assistantId: "widget-chat",
threadId: threadId,
filterSubagentMessages: true,
streamSubgraphs: true,
});
// Submit options
stream.submit(
{ messages: [...] },
{ streamSubgraphs: true, streamMode: ["values", "messages"] }
);
import { createDeepAgent } from "deepagents";
const agent = createDeepAgent({
model: llm,
tools: [...],
subagents: [
{
name: "CEO Finder",
description: "Find CEO information",
systemPrompt: "...",
tools: [...],
},
// ...more subagents
],
});
Expected Behavior
When a subagent is spawned via the task tool:
stream.subagents should contain the subagent's streaming data
stream.activeSubagents should list currently running subagents
Subagent internal tool calls should be visible
Actual Behavior
stream.subagents: Map(0) (always empty)
stream.activeSubagents: [] (always empty)
stream.toolProgress shows task tool calls correctly
Subagents execute successfully, but no streaming events are emitted
Root Cause Investigation
I traced the issue to createTaskTool in node_modules/deepagents/dist/index.js (line ~1428):
const result = await subagent.invoke(subagentState, config);
The subagent is invoked with invoke() which doesn't emit streaming events. The Python documentation mentions using stream() with subgraphs=True to get subagent events:
for namespace, chunk in agent.stream(
{"messages": [...]},
stream_mode="updates",
subgraphs=True,
):
if namespace: # Subagent event
print(f"[subagent: {namespace}]")
Attempted Fix
I tried patching invoke() to stream() with subgraphs: true:
let result = null;
const streamConfig = { ...config, subgraphs: true };
for await (const chunk of await subagent.stream(subagentState, streamConfig)) {
result = chunk;
}
This didn't work because the streaming events are consumed inside the tool closure and not propagated to the parent graph's stream.
### Environment / System Info
_No response_