Claude Fable 5 Model Support / Claude Code v2.1.170

What

Claude Fable 5 is now a supported model in Claude Code, positioned as the most capable option for the hardest and longest-running tasks.

Usage

claude --model fable
claude --model claude-fable-5

Details

Alias fable (and fable[1m] for 1M context) resolve to Fable 5
Full model IDs: claude-fable-5 (firstParty, vertex, foundry, gateway), anthropic.claude-fable-5 (Bedrock/Mantle)
Context window: 64k default output / 128k max — same as Opus 4.8
Default effort level: high (same as Opus 4.8)
Fable 5 appears at the top of the /model picker for eligible accounts
A companion model, claude-mythos-5, is also registered internally for the safety-refusal fallback lane
The /model command's help text now reads: "Provide an alias for the latest model (e.g. 'fable', 'opus', or 'sonnet') or a model's full name (e.g. 'claude-fable-5')."

Evidence

Model ID registration and picker entry (search for "claude-fable-5" and "Fable 5 · Most capable for your hardest and longest-running tasks")

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

The build it came inv2.1.170

9 Jun 2026 · 15 entries, this one is #1.

Either side of it

Open the release →

Names in this entry

settingfable
The full Claude Desktop managed-config schema, covering MCP policy and egress limits, is now bundled in.
modelclaude-fable-5
Opus 5 is now the default Opus, with a 1M-context option in the model picker.
settinghigh
The bundled Claude API skill docs now target the new Opus, covering thinking defaults, fallbacks and fast mode.
slash/model
Switch the AI model and save it as your default for new sessions. For models that support it, use left/right arrows to adjust effort level. With no argument, opens a picker; press s on a row to switch for the current session only. See when Claude Code asks you to confirm the switch. Once you confirm the switch, if Claude Code asks, Claude Code applies the change without waiting for the current response to finish. Before v2.1.242, Claude Code decided from a feature flag it fetched from Anthropic whether to run the command mid-turn or queue it until the turn finished, and always queued it in a session that doesn't fetch feature flags, such as on a third-party provider. Also available in non-interactive mode (-p) with a model argument instead of the picker, where it applies to the current session only and isn't saved as your default; requires Claude Code v2.1.205 or later
modelclaude-mythos-5
The model picker now colours Fable 5, Mythos 5 and Sonnet 5 in its list.

Is this right?

Other releases about the same thing. Found by shared names or similar wording; neither means one caused the other.