404 not_found_error
Cannot find or select Claude Fable 5
There is no model_not_found error type. A bad or unreachable model ID returns 404 not_found_error, and Claude Code shows its own message.
The 30-second version
The model ID is exactly claude-fable-5. On the API, a wrong or inaccessible ID returns 404 with error type not_found_error. In Claude Code you instead see a local message about the selected model, or Fable 5 simply missing from the picker. The four usual causes are a typo, an organization on zero data retention, a managed availableModels allowlist, and a Claude Code build older than v2.1.170.
Why the model is unreachable
Separate the API-level 404 from the Claude Code messages: they have different causes and different fixes.
Claude Code is too old
Fable 5 requires Claude Code v2.1.170 or later. Older versions do not show Fable 5 in the model picker and cannot select it. On the Anthropic API the picker lists Fable 5 only after the server reports it available for your organization, though typing /model fable checks availability directly.
An admin allowlist or model restriction
An organization admin can disable a model in the admin console, or exclude it through an availableModels allowlist in managed settings. Restricted models are hidden from the picker, and a restricted model set through --model or ANTHROPIC_MODEL is silently substituted with an allowed one plus a notice.
You are on a provider that uses its own model IDs
Amazon Bedrock, Google Cloud, Microsoft Foundry and LLM gateways define their own model names, so Claude Code passes any string through without validating it and the provider returns the error. On those platforms the model must also be enabled for your account and region.
Wrong model ID string
The ID is claude-fable-5, all lowercase with hyphens. Display names such as Fable 5, dotted forms, and IDs copied from another provider all fail. On the API this is a 404 not_found_error; in Claude Code the switch is rejected locally with a message that the model is not a recognized model id, usually with a suggestion.
Your organization is on zero data retention
Fable 5 is a Covered Model requiring 30-day retention and is not offered under zero data retention. Under ZDR the Claude Code model picker either omits Fable 5 or shows it disabled, and an organization default pointing at Fable 5 is skipped entirely.
Fix in this order
Check the cheap things first. Two of the five causes are fixed without talking to anyone.
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3. Confirm which credential is actually in use
Run /status and check that the active credential is the one you expect. A stray ANTHROPIC_API_KEY in the environment can route requests through a different account that has no Fable 5 access. Also check for a stale model value in --model, ANTHROPIC_MODEL or a settings file.
- 2
5. Ask your admin about model restrictions
If the model is restricted, it is hidden from the picker and no local change will reveal it. Ask your organization admin to enable Fable 5, or to add it to the availableModels allowlist in managed settings.
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4. Check your data retention configuration
If your organization is on zero data retention, enable 30-day retention for a single workspace under Privacy controls in the Console workspace settings. Other workspaces keep zero retention, and requests to Fable 5 from the enabled workspace start succeeding.
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2. Update Claude Code
Run claude update and restart. Fable 5 needs v2.1.170 or later. A full ID starting with claude- passes the local recognition check even on an older build, but the picker will still not list the model.
- 5
1. Verify the exact model ID
Use claude-fable-5 verbatim. In Claude Code, run /model with no argument to open the picker and choose from the models available to your account, or run /model fable, which checks availability with the server directly.
Reaching the model but getting empty responses?
If requests succeed with HTTP 200 but come back with no content, you are hitting a classifier refusal rather than an access problem.