feat: add ANTHROPIC_DEFAULT_FABLE_MODEL env vars + hide unsupported models in /model picker when CLAUDE_CODE_USE_BEDROCK=1

[rezaradmehr]

Preflight Checklist

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

What's Wrong?

When CLAUDE_CODE_USE_BEDROCK=1 and org uses Application Inference Profile ARNs (policy: no direct Anthropic API), the /model picker still shows Fable 5. Selecting it writes "model":
"eu.anthropic.claude-fable-5" into ~/.claude/settings.json, which calls Anthropic directly — bypassing Bedrock entirely. Result: 400 error ("data retention mode 'default' is not
available for this model") and a policy violation.

Additionally, there is no ANTHROPIC_DEFAULT_FABLE_MODEL env var, so even if the org creates a Bedrock inference profile for Fable, there is no supported way to wire it up — unlike
Sonnet/Haiku/Opus which all have ANTHROPIC_DEFAULT_*_MODEL env vars.

What Should Happen?

1. ANTHROPIC_DEFAULT_FABLE_MODEL (+ _NAME, _DESCRIPTION) env vars should exist, matching the pattern for the other three models.

2. When CLAUDE_CODE_USE_BEDROCK=1, the /model picker should only show models that have a corresponding ANTHROPIC_DEFAULT_*_MODEL ARN configured. Selecting a model with no ARN should
   be blocked or show a warning — it should never write a bare model ID string into settings.json.

Error Messages/Logs

Steps to Reproduce

1. Set CLAUDE_CODE_USE_BEDROCK=1 in ~/.claude/settings.json env block
2. Configure ANTHROPIC_DEFAULT_SONNET_MODEL, _HAIKU_MODEL, _OPUS_MODEL with Bedrock ARNs (do NOT set any Fable ARN — none exists)
3. Run Claude Code and type /model
4. Observe: "Fable 5" appears in the picker
5. Select Fable 5
6. Observe: settings.json now contains "model": "eu.anthropic.claude-fable-5"
7. Send any message
8. Observe: 400 error — request goes to Anthropic direct instead of Bedrock

Claude Model

Other

Is this a regression?

No, this never worked

Last Working Version

No response

Claude Code Version

2.1.170

Platform

AWS Bedrock

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

No response

[github-actions]

Found 3 possible duplicate issues:

1. [BUG] API Error 400: data retention mode 'default' is not available for this model via AWS Bedrock #66594
2. Custom Bedrock models not discoverable in /model command list #10169
3. [BUG] /model picker on Bedrock only shows one model per family, ignoring availableModels in settings.json #52310

This issue will be automatically closed as a duplicate in 3 days.

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[github-actions]

This issue has been automatically closed as a duplicate of #66594.

If this is incorrect, please re-open this issue or create a new one.

🤖 Generated with Claude Code