Claude Fable 5.2 Becomes Claude Code's Default Fable Model, Copilot Puts It Behind an Admin Policy, and Copilot CLI v1.0.108 Goes Stable

At a glance

• Claude Code now uses the new Fable model as its default Fable choice.
• The same Claude Code release closes a token leak in MCP sign in and two sandbox gaps.
• Copilot adds the new Fable model, but it may stay hidden until an admin policy is turned on.
• The Copilot CLI build with repository indexing commands is now the default install.

Monday broke the weekend lull. The npm latest tags for Claude Code and Copilot CLI both moved, and GitHub posted a model availability note before noon ET, while both Cursor changelogs stayed unchanged. Developers will see Fable 5.2 as the default Fable choice in Claude Code, may not see it in Copilot until a policy is on, and can take a stable Copilot CLI upgrade today.

Treat today as a model and upgrade day: move Claude Code to v2.1.321 or later for the security fixes even if you never pick Fable, check whether Fable 5.2 appears in your Copilot model picker, and upgrade Copilot CLI to v1.0.108 now that it is stable.

Top Stories

1. Claude Fable 5.2 ships and Claude Code v2.1.321 makes it the default Fable model

Anthropic announced Claude Fable 5.2 and Claude Mythos 5.2 on 9 November 2026. The announcement says both are the same underlying model, that Fable carries cybersecurity and biology safeguards so it can be offered to all users, and that Mythos access goes through Anthropic's verification programs. Anthropic says the 5.2 models generate output up to 30% faster than the 5.1 generation and cost less, with an optional fast mode. The model overview page lists a 1M token context window, 128K maximum output, and the model ID claude-fable-5-2.

Claude Code v2.1.321 posted on GitHub at about 2:22 PM ET on Monday. Its first line adds Claude Fable 5.2 and makes it the default Fable model. The announcement notes that Medium effort is the default in Claude apps and Claude Code, and says Fable 5.2 can finish hard tasks with fewer tokens than Fable 5.1 at that setting.

The same release carries fixes that matter whether or not you use Fable. MCP OAuth requests no longer send secrets such as refresh tokens to another host when a server redirects them. A read only Bash command no longer runs outside the sandbox without a permission prompt, and Bash permission checks no longer judge a file write from the wrong folder. Deny rules and protected file prompts now apply to the file that a cp or mv into a directory writes. npm latest and next both point to v2.1.322, posted that evening with one provider specific line, while stable stays at v2.1.311.

Practical dev impact: Upgrade to v2.1.321 or later this week for the OAuth and sandbox fixes alone. Whether you switch to Fable 5.2 depends on your plan, so check that Fable is included before you change a team default.

2. Claude Fable 5.2 reaches GitHub Copilot, with the policy off by default

GitHub posted at about 11:46 AM ET on 9 November that Claude Fable 5.2 is available to Copilot Pro+, Max, Business, and Enterprise users. The post lists the model picker in VS Code, Visual Studio, Copilot CLI, the Copilot coding agent, the Copilot app, github.com, GitHub Mobile, JetBrains IDEs, Xcode, and Eclipse, and says the rollout is gradual. The model is billed at provider list pricing under usage based billing.

Business and Enterprise administrators must enable the Claude Fable 5.2 policy in Copilot settings, and the policy is off by default. Our read: if the model is missing from your picker, that policy is the first place to look, after allowing for a gradual rollout. GitHub says Fable 5.2 requires data retention by default, so Anthropic keeps prompts and outputs to run safety classifiers, and that retained data is not used to train Anthropic's models. Enabling the policy counts as acknowledging that requirement. Eligible enterprises can use Fable 5.2, Fable 5.1, and Fable 5 with zero data retention through the end of the calendar year under a time bound exemption.

Practical dev impact: Our read: try the picker in the editor or CLI you already use. If Fable 5.2 is not there, read the retention note before you ask for the policy to be turned on, because enabling it acknowledges that requirement.

3. Copilot CLI v1.0.108 is now the stable default

Copilot CLI v1.0.108 published on GitHub at about 11:20 AM ET on Monday, and npm latest for @github/copilot now points to it. This is new since Sunday's brief, when v1.0.108 existed only as prerelease builds and v1.0.107 was the default.

The stable notes add /index commands and turn on managed shared tgrep indexing by default for eligible repositories. They also restart a running local MCP server after /cd when the sandbox is on, and creating an SDK session with two custom tools of the same name is now an error.

The prerelease tag already points to v1.0.109-1, posted at about 12:40 AM ET today. It adds Claude Fable 5.2 to the CLI model picker under New models and adds IPv4 and IPv6 CIDR support for sandbox host allow and deny rules.

Practical dev impact: Move everyday machines to v1.0.108 now, then try v1.0.109-1 on a test machine only if you need its sandbox CIDR rules or the Fable 5.2 picker before a later stable build lands.

Practical Impact Analysis

Our read: the same model is arriving in two developer tools with different defaults. Claude Code v2.1.321 makes Fable 5.2 the default Fable choice and also fixes an OAuth redirect that could send refresh tokens to another host, plus two cases where Bash commands skipped a prompt, so the upgrade is worth doing even if you never pick Fable. Copilot adds the model to a long list of surfaces, but Business and Enterprise users may not see it until an off by default policy is on, and the CLI has a stable indexing release you can install today.

The rest of the board is quiet. Codex latest is still v0.167.0 and Gemini CLI latest is still v0.67.0. Both Cursor changelogs are unchanged. If you have one hour, upgrade Claude Code and Copilot CLI, try one real task on Fable 5.2 where your plan includes it, and check the Copilot model picker in the tool you already use.

Tutorial

1. Open a test shell. The active commands below only print registry tags and installed versions.
2. Run step 1 to print the npm tags for Claude Code and Copilot CLI and your local versions.
3. Uncomment a line in step 2 only if you want the pinned stable builds or a one session Fable 5.2 trial.
4. Read step 3 if Fable 5.2 is missing from your Copilot model picker.

# We have not run this script end to end on every platform. It prints and checks, and changes no files.
# Run it in a test shell. Nothing is written to your shell profile.

# 1. Snapshot at 5:55 AM ET Tue 10 Nov 2026, npm registry channel:
#    @anthropic-ai/claude-code latest v2.1.322, next v2.1.322, stable v2.1.311
#    @github/copilot latest v1.0.108, prerelease v1.0.109-1
npm view @anthropic-ai/claude-code dist-tags.latest dist-tags.stable
npm view @github/copilot dist-tags.latest dist-tags.prerelease
if command -v claude >/dev/null; then claude --version; else echo "no claude CLI on PATH"; fi
if command -v copilot >/dev/null; then copilot --version; else echo "no copilot CLI on PATH"; fi

# 2. Optional installs only. Pinned at 5:55 AM ET Tue 10 Nov 2026, npm registry channel:
# npm install -g @anthropic-ai/claude-code@2.1.322
# npm install -g @github/copilot@1.0.108
#    One session Fable 5.2 trial in Claude Code, if your plan includes Fable:
# claude --model claude-fable-5-2
#    Test machine only, npm prerelease channel, not for production:
# npm install -g @github/copilot@1.0.109-1

# 3. Copilot Fable 5.2 policy (GitHub, 9 Nov 2026):
#    Business and Enterprise admins enable it in Copilot settings. Off by default.
#    Requires data retention by default. Enabling the policy acknowledges this.
#    Changelog: https://github.blog/changelog/2026-11-09-claude-fable-5-2-in-github-copilot/

echo "Done. Nothing was installed or changed on disk."

If npm view shows newer tags, refresh before you pin.

Sources:

• Introducing Claude Fable 5.2 and Claude Mythos 5.2
• Claude Fable 5.2 model overview
• Claude Code v2.1.321 release
• Claude Fable 5.2 in GitHub Copilot
• Copilot CLI v1.0.108 release
• Copilot CLI v1.0.109-1 release
• Cursor changelog
• Cursor CLI changelog
• GitHub Changelog

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