AI agents stopped fabricating resource identifiers

aalises

·Apr 10, 2026·#28342fix(ai-builder): Prevent orchestrator and planner from assuming resource identifiers (no-changelog)

n8n's AI builder no longer invents Slack channels, calendars, or spreadsheets when users don't mention them — orchestrator and planner prompts now explicitly prevent fabricated resource identifiers.

When users asked the AI builder to send a Slack message, the orchestrator and planner agents would sometimes assume a channel like #general without being asked. The builder would then fail to find this fabricated resource and ask the user about a channel they never mentioned, creating unnecessary confusion.

Prompt guardrails have been added at two levels to prevent this behavior. The orchestrator system prompt now instructs agents to mention integrations by service name (Slack, Google Calendar) but not specify which channels, calendars, spreadsheets, or folders to use. The planner prompt received similar treatment, with explicit guidance to never default resource identifiers the user didn't mention, and field-level rules ensuring trigger descriptions, integrations lists, and assumptions don't leak resource identifiers through.

This fix applies to the instance AI package responsible for workflow building automation.

View Original GitHub Description

Summary

The orchestrator and planner agents were fabricating resource identifiers (e.g. defaulting to #general for Slack channels) when the user didn't specify one. The builder would then try to resolve the fabricated identifier, fail, and ask the user about a resource they never mentioned — causing confusion.

This adds explicit prompt guardrails at two levels:

Orchestrator system prompt (system-prompt.ts): instructs the orchestrator to mention integrations by service name but not specify which channels, calendars, spreadsheets, folders, or other resources to use.
Planner prompt (plan-agent-prompt.ts): adds a peer-level rule against defaulting resource identifiers, plus explicit field-level guidance for integrations, assumptions, and triggerDescription to prevent resource identifiers from leaking through any blueprint field.

Related Linear tickets, Github issues, and Community forum posts

https://www.notion.so/n8n/InstanceAI-assumes-a-slack-channel-without-me-mentioning-one-33c5b6e0c94f80c493d1f14335b75e0c

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Docs updated or follow-up ticket created.
Tests included.