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Claude Code Issues / #55521

Linear MCP save_issue triggers persistent Cloudflare block after burst of parallel requests

Resolved 💬 2 comments Opened May 2, 2026 by nickwarters Closed Jun 3, 2026

Description

After making a burst of parallel save_issue calls via the claude.ai Linear MCP integration, the MCP proxy IP gets blocked by Cloudflare. The block persists indefinitely — it has not self-healed after 12+ hours and multiple session restarts.

Steps to reproduce

  1. Use the mcp__claude_ai_Linear__save_issue tool to create Linear issues
  2. Send a burst of 5–7 parallel save_issue calls in a single response (as the model naturally does when creating independent issues in parallel)
  3. Some calls in the burst succeed; subsequent calls begin returning Cloudflare 403 blocks
  4. All further save_issue calls fail with the same Cloudflare block — including in new sessions started hours or days later

Error response

Every subsequent call returns an HTML Cloudflare block page instead of a JSON response:

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>

Details

  • MCP server: claude.ai Linear (mcp__claude_ai_Linear__save_issue)
  • Affected operation: save_issue (create new issue)
  • Trigger: burst of ~7 parallel tool calls in a single model response
  • Observed proxy IPs blocked: 185.195.59.152, 86.137.238.98
  • Cloudflare Ray IDs (sampled): 9f511503efaa6d50, 9f5116b5eedf6d50, 9f5117122b6b6d50, 9f511bc729d44343, 9f512c664ae1d8a1, 9f513b6eed997733, 9f5550ac1c0cef46
  • Duration: block persists 12+ hours across multiple claude --resume sessions
  • Workspace: linear.app/nickwarters

Impact

Once triggered, the Linear MCP integration is completely non-functional for issue creation. The block survives session restarts and does not self-heal on any observed timescale.

In this specific case, 10 of 39 planned issues were successfully created before the block triggered. The remaining 29 issues cannot be created via the MCP and must be created manually.

Expected behaviour

Either:

  • The MCP proxy should not trigger Cloudflare WAF rules when making legitimate burst API calls to Linear, or
  • The MCP proxy IPs should be allowlisted / the requests rate-limited client-side before the burst reaches Cloudflare, or
  • The block should self-heal on a predictable short timescale (e.g. 5–10 minutes)

Workaround

None found. The block appears to be on the Anthropic MCP proxy infrastructure's IP(s) rather than being session- or user-specific, so there is no client-side workaround available.

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