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Claude Code Issues / #35595

[BUG] Built-in Atlassian MCP connector: write operations blocked by Cloudflare after burst of requests

Resolved 💬 2 comments Opened Mar 18, 2026 by paulammer-noda Closed Apr 16, 2026

Preflight Checklist

  • [x] I have searched existing issues and this hasn't been reported yet
  • [x] This is a single bug report (please file separate reports for different bugs)
  • [x] I am using the latest version of Claude Code

What's Wrong?

After creating ~8 Jira issues in quick succession using the built-in Atlassian MCP connector (mcp__claude_ai_Atlassian__createJiraIssue), all subsequent write operations using createJiraIssue become permanently blocked by Cloudflare with a "Sorry, you have been blocked / You are unable to access anthropic.com" error.

Read operations (getJiraIssue, searchAtlassian, etc.) continue to work. Other write operations (like createIssueLink and editJiraIssue) still work. Only the specific createJiraIssue gets blocked. The block persisted across a 12+ hour wait and across IP changes including a VPN, suggesting it is tied to the session/auth token rather than the client IP.

What Should Happen?

Write operations should either succeed or return a structured rate-limit error (e.g., HTTP 429 with retry-after) that Claude Code can surface to the user. The raw Cloudflare HTML block page should not be passed back as the tool error.

Error Messages/Logs

Streamable HTTP error: Error POSTing to endpoint: <!DOCTYPE html>
  ...
  <title>Attention Required! | Cloudflare</title>
  ...
  <h1>Sorry, you have been blocked</h1>
  <h2>You are unable to access anthropic.com</h2>
  ...
  Cloudflare Ray ID: 9ddf0b57f87ab208

Additional Ray IDs from subsequent blocked attempts: 9de09c0e1d95d6f0, 9de0a3f3ca51389a

Steps to Reproduce

  1. Use the built-in Atlassian MCP connector in Claude Code
  2. Call createJiraIssue ~6-8 times in quick succession (e.g., creating tickets for a new epic)
  3. Observe that subsequent createJiraIssue calls return a Cloudflare HTML block page instead of a JSON response
  4. Note that getJiraIssue and other read operations continue to work normally
  5. Wait 12+ hours and retry — block persists
  6. Switch to a VPN (different IP) and retry — block persists

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.78 (Claude Code)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

iTerm2

Additional Information

  • Claude Code CLI on macOS 14.1
  • Using the built-in Atlassian MCP connector (not a self-hosted server)
  • Read operations work fine throughout the entire block period, did not try other write actions like editJiraIssue until the next morning, and found they worked fine (but still blocked on createJiraIssue)

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