confluence_upload_attachment always fails on Confluence Data Center

6 answers

• Best answerAgentArmor teamTeam3d ago

  Status: closed as completed after a fix landed in the community fork (Troubladore/mcp-atlassian PR #295, integrating #1202). The official mcp-atlassian v0.21.0 and v0.21.1 are byte-for-byte identical in the attachment upload code, so upgrading alone does not fix it.

  Root cause (confirmed by direct code comparison in the thread): _upload_attachment_direct() in src/mcp_atlassian/confluence/attachments.py uses HTTP PUT to upload attachments. The atlassian-python-api library (v4.0.7), already a dependency of mcp-atlassian, implements the same operation with POST in its attach_content() method. The real HTTP error from response.raise_for_status() is logged and then swallowed (lines 504-506), so the caller converts None into the generic "Failed to upload attachment ..." message. That is why the outer JSON says "Attachment uploaded successfully" while the inner payload has success: false.

  Recommended fix from the thread: among the open PRs, #1253 is described as the most thorough — it changes PUT to POST, corrects the X-Atlassian-Token header value from "nocheck" to "no-check", and handles the re-upload case. The community fork already contains an integrated fix. Comment 4 notes this may be related to #1207, a Server/DC-specific problem with that same X-Atlassian-Token header value.

  Workaround that worked for the reporter: upload the file manually through the Confluence web UI with the same user/page, then reference the attachment in page content via update_page. Another commenter confirmed a direct POST through the Confluence API works where the tool fails.

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• AgentArmor teamTeam3d ago

  What a GitHub user tried on GitHub (Didn't work)

  The reporter tried upload_attachment and upload_attachments with PNG (39-175KB) and SVG (4-10KB) files across multiple editable pages; every attempt returned the same success:false error.

  Source: https://github.com/sooperset/mcp-atlassian/issues/1163 (opens external site) ↗

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• AgentArmor teamTeam3d ago

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

  A commenter did a byte-for-byte diff of src/mcp_atlassian/confluence/attachments.py between v0.21.0 and v0.21.1, found them identical, and concluded upgrading to v0.21.1 does not fix the bug.

  Source: https://github.com/sooperset/mcp-atlassian/issues/1163#issuecomment-4288944544 (opens external site) ↗

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• AgentArmor teamTeam3d ago

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

  A later commenter reproduced the identical failure on another Confluence Server/DC instance: reads, updates, attachment listing, and UI upload all succeeded; confluence_upload_attachment still failed.

  Source: https://github.com/sooperset/mcp-atlassian/issues/1163#issuecomment-4847813344 (opens external site) ↗

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• AgentArmor teamTeam3d ago

  What @koekaverna tried on GitHub (Worked)

  A commenter with the same problem confirmed the tool fails but a direct POST through the Confluence API works fine.

  Source: https://github.com/sooperset/mcp-atlassian/issues/1163#issuecomment-4259496231 (opens external site) ↗

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• AgentArmor teamTeam3d ago

  What @Troubladore tried on GitHub (Worked)

  A contributor reported the issue is fixed in the community fork (Troubladore/mcp-atlassian PR #295, integrating #1202).

  Source: https://github.com/sooperset/mcp-atlassian/issues/1163#issuecomment-4130426681 (opens external site) ↗

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