Output blocked by content filtering policy - false positive when generating LICENSE (BSL 1.1) and API documentation

Bug Report

Description

Claude Code (Opus 4.6) repeatedly fails with Output blocked by content filtering policy when attempting to generate two specific file types:

1. LICENSE file — BSL 1.1 (Business Source License) text
2. API documentation — MCP (Model Context Protocol) tools reference (docs/api/mcp-tools.md)

The content filter appears to be triggering a false positive on legitimate software documentation output.

Error Details

API Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"Output blocked by content filtering policy"},"request_id":"req_011CXwFHrArMdeo6s7pPcu5J"}

API Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"Output blocked by content filtering policy"},"request_id":"req_011CXwFHrArMdeo6s7pPcu5J"}

API Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"Output blocked by content filtering policy"},"request_id":"req_011CXwFwskfGr2qDvBX5G4ue"}

Request IDs:

• req_011CXwFHrArMdeo6s7pPcu5J (triggered twice)
• req_011CXwFwskfGr2qDvBX5G4ue (triggered once)

Context

• Model: Claude Opus 4.6 (claude-opus-4-6)
• Platform: Windows 11 (win32)
• Task: Phase 8 of a .NET 10 project (MaginoryOS) — creating documentation files as part of an enterprise hardening phase
• Tool used: Write tool to create files

Steps to Reproduce

1. Start a Claude Code session with Opus 4.6
2. Work on a .NET project with Clean Architecture
3. Ask Claude to create a BSL 1.1 LICENSE file (standard open-source license text)
4. Or ask Claude to create MCP API tool documentation in markdown format
5. The Write tool call gets blocked by the content filter before output is generated

Expected Behavior

Claude should be able to generate:

• Standard software license files (BSL 1.1 is a well-known license used by MariaDB, CockroachDB, Sentry, etc.)
• API documentation in markdown format describing JSON-RPC tool parameters

Actual Behavior

The API returns HTTP 400 with "Output blocked by content filtering policy". Claude Code shows the error and the assistant's response is empty/blocked. The user sees Claude appearing to "stop" or "freeze" without producing any output.

Impact

• Blocks legitimate software development workflow
• User cannot complete documentation phase of their project
• Multiple retries produce the same error, wasting API credits
• No indication of what content triggered the filter, making workarounds impossible

Additional Notes

• The conversation had been running for a long session (Phase 8 implementation with 7 sub-phases)
• Previous file writes in the same session (C# source files, Razor components, CSS, Dockerfile) all succeeded
• Only the LICENSE and API docs markdown files triggered the filter
• The content being generated is entirely standard software documentation — no harmful, sensitive, or policy-violating content

Suggestion

The content filter may need adjustment to avoid false positives on:

• Well-known open-source license texts (BSL, MIT, Apache, GPL, etc.)
• API/tool documentation in markdown format
• JSON-RPC protocol documentation with parameter schemas