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fix: avoid 502 on long-running agents via non-blocking + polling #8

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1c90cf3
Fix 502 on long-running agents via non-blocking + polling
leomartin-malt30 Jun 1, 2026
40f5d4c
Expose chainOfThought, conversationTitle, and rawConversation in output
leomartin-malt30 Jun 1, 2026
d283948
Surface agent-generated files (CSV, HTML, text…) in output
leomartin-malt30 Jun 1, 2026
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67 changes: 66 additions & 1 deletion README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -55,18 +55,80 @@ Follow the [installation guide](https://docs.n8n.io/integrations/community-nodes
- **Parameters:**
- Message: `What is the latest update on project X?`
- Agent: (Select from dropdown)
- Additional Fields (optional): Username, Email, Timezone
- Additional Fields (optional): Username, Email, Full Name, Timezone, Wait For Completion, Poll Interval (Ms), Max Wait (Ms), Include Generated File Content, Max Generated File Size (Bytes)

**Output:**

```
{
"agentMessage": "Project X is on track for delivery next week.",
"chainOfThought": "Looking up the project in Jira, then cross-referencing with the latest standup notes...",
"conversationId": "ivxVYkiwhA",
"conversationTitle": "Project X delivery update",
"conversationUrl": "https://dust.tt/w/{workspaceId}/assistant/{conversationId}",
"generatedFiles": [
{
"fileId": "fil_4aO6lmikIV63Bi",
"title": "jirateam_1780301864867_1.txt",
"contentType": "text/plain",
"snippet": "Found 70 issue(s)...",
"downloadUrl": "https://dust.tt/api/w/{workspaceId}/files/fil_4aO6lmikIV63Bi?action=download",
"fromToolName": "get_issues_using_jql",
"fromActionSId": "act_se8GjPQjCZzVwY",
"size": 161234,
"responseContentType": "text/plain; charset=utf-8",
"content": "Found 70 issue(s) using JQL\n\n# DATA-10998..."
}
],
"rawConversation": { /* full conversation object including actions, citations, generated files */ },
"userMessage": { ... }
}
```

| Field | Description |
|---|---|
| `agentMessage` | Final answer text from the agent (markdown). |
| `chainOfThought` | Reasoning trace if the agent's model supports it (Sonnet/Opus thinking models). `null` otherwise. |
| `conversationId` | Dust `sId` of the conversation. Use it to send follow-up messages or to open the conversation in the Dust UI. |
| `conversationTitle` | Title auto-generated by Dust once the agent finishes. `null` if not set. |
| `conversationUrl` | Direct link to the conversation in the Dust UI. |
| `generatedFiles` | Array of files the agent generated during the run (e.g. CSV/text/HTML attachments produced by tool calls). Always populated with metadata; the actual content is inlined when **Include Generated File Content** is on. Empty array if the agent produced none. |
| `rawConversation` | The full conversation object (`content`, `actions`, `citations`, `generatedFiles`, …). Useful to extract tool outputs, file IDs, or per-action details downstream. Can be large for agents that make many tool calls. |
| `userMessage` | The first user message in the conversation, including the resolved user object. |

#### Generated files

When the agent produces files during its run (Jira extracts, CSV exports, HTML visualizations, …), they show up in the `generatedFiles` array. Each entry contains:

| Sub-field | Description |
|---|---|
| `fileId` | Dust file ID (`fil_…`). |
| `title` | Display name of the file (e.g. `report.csv`). |
| `contentType` | Content-Type reported by Dust at generation time. |
| `snippet` | Short preview Dust attaches to the file metadata. |
| `downloadUrl` | Full HTTPS URL to `GET` the raw content (uses the same Dust API key for auth). |
| `fromToolName` / `fromActionSId` | Which tool call produced the file. `null` when the file is attached to the agent message itself. |
| `size` | Byte length of the downloaded content (only present when downloaded). |
| `responseContentType` | Content-Type returned by the download endpoint (only present when downloaded). |
| `content` | UTF-8 string content for textual files (HTML, CSV, JSON, Markdown, YAML, plain text, …). Only present when **Include Generated File Content** is on. |
| `contentBase64` | Base64-encoded content for binary files (images, PDFs, …). Only present when **Include Generated File Content** is on. |
| `tooLarge` | `true` if the file exceeded **Max Generated File Size (Bytes)** — content is omitted to keep the workflow output sane. |
| `downloadError` | Error message if the download itself failed. The rest of the workflow continues. |

#### Long-running agents & polling

The node creates a conversation and then **polls** the Dust API until the agent finishes, before returning the final `agentMessage`. This matches the pattern used by Dust's own clients and avoids `502 Bad Gateway` errors that previously occurred for agents that take more than ~30 seconds (e.g. agents that call out to Jira, Slack, Google Docs, or other slow tools).

You can tune the polling behavior via Additional Fields:

| Field | Default | What it does |
|---|---|---|
| `Wait For Completion` | `true` | If off, the node returns immediately with just `{ conversationId, conversationUrl, userMessage }`. Use this when you want to manage polling yourself (e.g. with an HTTP Request + Wait loop). |
| `Poll Interval (Ms)` | `1500` | Time between polling attempts while the agent is running. |
| `Max Wait (Ms)` | `120000` | Hard ceiling on the total wait. If the agent has not reached `succeeded` by then, the node throws. |

If the agent ends in `failed` or `cancelled`, the node throws with the error message from Dust. The conversation URL is included in the error so you can inspect it in the Dust UI.

### Upload a Document

- **Operation:** Upload a Document
Expand Down Expand Up @@ -103,6 +165,9 @@ Add these credentials in n8n under the "Dust API" credential type and reference

## Version history

- Unreleased
- Fix `502 Bad Gateway` for long-running agents by switching from blocking POST to non-blocking POST + polling on `GET /conversations/{id}`. Adds `Wait For Completion`, `Poll Interval (Ms)`, `Max Wait (Ms)`, and `Full Name` fields. Output now also includes `conversationId`, `chainOfThought`, `conversationTitle`, and `rawConversation`.
- Surface files the agent generates during the run as a top-level `generatedFiles` array. Adds `Include Generated File Content` (default on) and `Max Generated File Size (Bytes)` (default 10 MB) fields; textual files come back as inlined `content`, binary files as `contentBase64`.
- 0.1.1
- Add SkipToolsValidation + rename assitant to agent
- 0.1.0
Expand Down
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