---
title: "Notion API Upgrade prompts for Custom Agent tools in Notion MCP: 2026-09-01 | Harbyn"
description: "Notion API Upgrade prompts for Custom Agent tools in Notion MCP, announced Sep 1, 2026."
canonical: "https://harbyn.com/changes/notion/2026-09-01-upgrade-prompts-for-custom-agent-tools-in-notion-mcp"
last-updated: 2026-10-02
---

# Notion API Upgrade prompts for Custom Agent tools in Notion MCP

Markdown version of <https://harbyn.com/changes/notion/2026-09-01-upgrade-prompts-for-custom-agent-tools-in-notion-mcp>.

Behavior change - Notion API. low severity. In effect.

Notion MCP Custom Agent tools (notion-list-agents, notion-search-agents and the session tools) now return a prompt with a recovery link when the workspace lacks Notion AI and Custom Agents, instead of a generic permission error. notion-fetch with the id self reports these tools as upgrade\_required or plan\_required; workspaces with a billing restriction still get a permission error and a not\_enabled status.

## Facts

| Fact | Value |
| --- | --- |
| Vendor | [Notion API](https://harbyn.com/vendors/notion.md) |
| Kind | Behavior change |
| Severity | low |
| Status | In effect |
| Announced | Sep 1, 2026 |
| Added to Harbyn | Oct 2, 2026 |
| Lead time | No dated deadline |
| Review | Reviewed by a person, extracted by a deterministic parser |

## Find it in your code

```sh
npx harbyn scan
```

This change names no identifier the scanner can match line by line, so the scan tells you whether your repository uses Notion API, from its packages and API hosts. Nothing leaves your machine.

## Sources

Where this event comes from: the page we read, when we read it, and the hash of that snapshot.

- <https://developers.notion.com/page/changelog.md> (changelog, fetched 2026-10-02 22:20 UTC, sha256 `ec279fb11111f1773751e95d79200a14dbac9e5c21565900e74f4509ca8de3e9`)

## Related changes

### More from Notion API

- [Free workspace block limits now apply to the REST API](https://harbyn.com/changes/notion/2026-09-01-free-workspace-block-limits-now-apply-to-the-rest-api.md) (Breaking change, announced Sep 1, 2026)
- [notion-search is now keyword-only](https://harbyn.com/changes/notion/2026-09-02-notion-mcp-splits-keyword-search-and-ai-search.md) (Behavior change, announced Sep 2, 2026)
- [Content queries to notion-search can route to AI search](https://harbyn.com/changes/notion/2026-09-10-ai-search-accepts-filters-and-notion-search-routes-content-queries-to-it-2.md) (Behavior change, announced Sep 10, 2026)
- [Custom Agent session tools return specific validation and conflict errors](https://harbyn.com/changes/notion/2026-09-10-validation-and-conflict-errors-from-custom-agent-session-tools.md) (Behavior change, announced Sep 10, 2026)

### Changes at other vendors

- [Amazon Selling Partner API: ORDER\_CHANGE notifications add PreFulfillmentStatusChange for Amazon Autos](https://harbyn.com/changes/amazon-sp-api/2026-10-14-sp-api-updates-new-listings-items-api-ivp-values-in-eu5-jp-and-ca-stores-oct-3.md) (effective Oct 28, 2026)
- [BigCommerce: 301 redirects will apply only to storefront channels](https://harbyn.com/changes/bigcommerce/2026-10-07-301-redirects-now-apply-to-storefront-channels-only.md) (effective Nov 10, 2026)
- [GitHub: Secret scanning audit log business field changes to enterprise slug](https://harbyn.com/changes/github/2026-10-20-updates-to-github-secret-scanning-7.md) (effective Nov 12, 2026)
- [Jira / Atlassian Cloud: New IP address ranges in use from January 1, 2027](https://harbyn.com/changes/atlassian-jira/2026-10-16-atlassian-cloud-adds-new-ip-address-ranges.md) (effective Jan 1, 2027)

[All upcoming deadlines](https://harbyn.com/deadlines.md)