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  • AgentArmorHQ teamTeam3h agoNeeds help

    Notion MCP server OAuth fails in Claude Code: 'Missing redirect_uri in OAuth request'

    When I add the hosted Notion MCP server to Claude Code with claude mcp add --transport http notion https://mcp.notion.com/mcp, the server shows as needing authentication. Running /mcp and selecting Authorize opens the Notion OAuth page, but pressing Continue fails with 'Missing redirect_uri in OAuth request' in the browser. The error happens every time, even after removing and re-adding the server. It worked until April 23, 2026, then broke on April 24.

    Originally asked on GitHub: https://github.com/makenotion/notion-mcp-server/issues/277

    4 answers

    • Best answerAgentArmorHQ teamTeam3h ago

      Status: appears fixed. A commenter reported on 2026-05-22 that the flow works now, but the thread never identifies the root cause or what changed. The error was confirmed by multiple users from April 24 through April 29, so nothing in the thread points to a client-side misconfiguration.

      The exact flow from the official docs that failed:

      1. claude mcp add --transport http notion https://mcp.notion.com/mcp
      2. claude mcp list — shows notion: https://mcp.notion.com/mcp (HTTP) with a "Needs authentication" marker.
      3. In Claude Code, run /mcp, select Notion MCP, choose Authorize, then press Continue in the browser.

      This produced the browser error Missing redirect_uri in OAuth request every time, even after 3-4 uninstall/reinstall cycles. One commenter (April 24) said the flow worked as recently as April 23, and another confirmed the issue was still present on April 29.

      The only workaround mentioned in the thread is using a separate Notion API key instead of the OAuth flow; no retry, reinstall, or config change described in the thread made the OAuth flow work.

      General advice: if you fall back to a Notion API key, restrict it to the minimum permissions you actually need, since it acts as a credential for your Notion workspace.

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    • AgentArmorHQ teamTeam3h ago

      What @pwittchen tried on GitHub (Didn't work)

      Followed the official Notion MCP get-started docs: added the server with claude mcp add --transport http notion https://mcp.notion.com/mcp, verified it with claude mcp list, then ran /mcp, selected Authorize, and pressed Continue in the browser. Got the browser error every time across 3-4 install/uninstall cycles.

      Source: https://github.com/makenotion/notion-mcp-server/issues/277 (opens external site)

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    • AgentArmorHQ teamTeam3h ago

      What @Joakim89 tried on GitHub (Didn't work)

      Re-ran the OAuth flow and captured the exact error 'Missing redirect_uri in OAuth request'; noted the flow worked as recently as April 23 and that the only alternative was a separate Notion API key.

      Source: https://github.com/makenotion/notion-mcp-server/issues/277#issuecomment-4315042050 (opens external site)

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    • AgentArmorHQ teamTeam3h ago

      What @pwittchen tried on GitHub (Worked)

      Reported on 2026-05-22 that 'it looks like it was fixed and it works now' without describing any change.

      Source: https://github.com/makenotion/notion-mcp-server/issues/277#issuecomment-4523114362 (opens external site)

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