store: Fix: N8N MCP partial updates corrupt workflows via typeVersion bumps

graph/fixes/fix-n8n-mcp-partial-updates-corrupt-workflows-via-typeversio-c30705.md

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+---
+id: c3070599-c723-4993-bada-3103e6f03e53
+type: fix
+title: "Fix: N8N MCP partial updates corrupt workflows via typeVersion bumps"
+tags: [n8n, mcp, n8n-mcp, typeversion, workflow-corruption, fix]
+importance: 0.85
+confidence: 0.8
+created: "2026-03-01T15:58:45.259930+00:00"
+updated: "2026-03-01T15:58:45.259930+00:00"
+---
+
+# N8N MCP Partial Updates Can Corrupt Workflows
+
+## Problem
+Using `n8n_update_partial_workflow` to bump `typeVersion` values on nodes (e.g., `scheduleTrigger` 1.2→1.3, `if` 2→2.3) caused `"Cannot read properties of undefined (reading 'execute')"` errors. The workflow could no longer be activated after this corruption.
+
+## Root Cause
+The n8n MCP validator reports "latest" node versions that may not match what is actually installed in the running n8n instance. Bumping typeVersions via MCP to versions unsupported by the installed instance breaks node execution. The `onError` property updates also triggered this at older typeVersions.
+
+## Fix / Recovery
+Recovery required a full PUT via the n8n REST API with clean node definitions at the correct typeVersions (matching what was installed, not what MCP reported).
+
+## Rules Going Forward
+- **Never bump typeVersions via MCP** — only do typeVersion upgrades in the n8n UI
+- The n8n MCP `n8n_update_partial_workflow` tool is safe for content/logic changes but not for schema changes
+- The `onError` property can also cause corruption at older typeVersions — test carefully
+
+## Tags
+n8n, mcp, n8n-mcp, typeversion, workflow-corruption