[BUG] False-positive AUP block ([bio] classifier) on benign Google Sheets/Drive API discussion

### Preflight Checklist

- [x] I have searched [existing issues](https://github.com/anthropics/claude-code/issues?q=is%3Aissue%20state%3Aopen%20label%3Abug) 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?

## Summary
Mid-response generation was blocked by a usage-policy classifier tagged `[bio]`,
during a purely technical discussion of Google Drive/Sheets API tooling limitations.
The content had no relation to biology, biosecurity, or any sensitive topic.
## Request IDs
req_011Cessovsg6Xuqv7MVo3r7n
req_011CesuP9v3ErWRocaRRHxqW

## Context
Claude (Sonnet 5) was mid-sentence explaining why a Google Sheets API connector
with cell-level write support would remove a file-size constraint on spreadsheet
uploads via a Google Drive MCP connector. The exact sentence being generated when
the block fired was enumerating three technical options for working around a
tooling limitation (business-case spreadsheet editing for an investment justification gate in an PDLC workflow).
## Observed behavior
Response was cut off mid-sentence with:
"API Error: Sonnet 5 can't help with this. Start a new session to continue.
Learn more: https://www.anthropic.com/legal/aup
Details: `[bio]`"
## Expected behavior
No block — the content was a benign technical explanation with no plausible
connection to the [bio] policy category.
## Environment
Claude Code desktop app, Sonnet 5 (claude-sonnet-5)
## Attachment
Screenshot of the blocked response available on request (contains prior
conversation context).

### What Should Happen?

## Expected behavior
No block — the content was a benign technical explanation with no plausible
connection to the [bio] policy category.

### Error Messages/Logs

```shell
API Error: Sonnet 5 can't help with this. Start a new session to continue.

Learn more: https://www.anthropic.com/legal/aup

Details: `[bio]`

Request ID: req_011CesuP9v3ErWRocaRRHxqW
```

### Steps to Reproduce

No idea - see context above. Claude doesn't know either: it views the conversation as entirely benign.

### Claude Model

Sonnet (default)

### Is this a regression?

I don't know

### Last Working Version

_No response_

### Claude Code Version

2.1.247

### Platform

AWS Bedrock

### Operating System

Windows

### Terminal/Shell

Other

### Additional Information

_No response_

Start by reviewing the AWS Bedrock request records for req_011Cessovsg6Xuqv7MVo3r7n and req_011CesuP9v3ErWRocaRRHxqW, using the reported Claude Code desktop, Sonnet 5, and Google Drive/Sheets API context. Confirm whether the `[bio]` block can be reproduced and identify what evidence is needed to prevent or escalate the false positive.

索引モデルが issue の本文から書いたものです。