Workaround
Tokens from a public integration's OAuth aren't compatible with the remote MCP server; initiate OAuth with the MCP server (https://mcp.notion.com/mcp) instead.
The error
{"error":"invalid_token","error_description":"Invalid token format"}Reported in makenotion/notion-mcp-server issue #106: “401 using mcp.notion.com/mcp”.
What fixed it
the tokens acquired from OAuth directly with public integration in Notion aren't compatible with the remote MCP server. You'd have to initiate OAuth with the MCP server (https://mcp.notion.com/mcp)
— a maintainer's comment on the issue.
Source and dates
| Repository | makenotion/notion-mcp-server |
|---|---|
| Issue | 401 using mcp.notion.com/mcp |
| Evidence | a maintainer's comment |
| Status | Workaround (a way around it, given in the evidence) |
| Fixed in | No version is named |
| Issue closed | Not recorded |
| Read from GitHub | 2026-11-07 |
| Approved by a person | 2026-11-07 |
This page records what the vendor's own GitHub repository says. The error text, the issue title and the quote are copied as written; the summary at the top is one sentence limited to the quote, and a person approved this fact on 2026-11-07. KanseiLink has not re-run the fix. Read the issue before applying it. Something changed? Write to contact@synapse-arrows.com.
For AI agents
The same fact is returned as issue_facts by lookup({ service_id: 'notion' }) on the KanseiLink MCP server (https://mcp.kansei-link.com/mcp), next to the other checked facts for Notion. Connection guide: Notion service page.