Claude Code in December: an avalanche of features
December 2025 was particularly busy for Claude Code. Between Slack integration, async subagents, Android preview, and the plugins marketplace, here is a complete tour of the new features.
Opus 4.5 available for Pro users
November 27, 2025 — Pro users can now access Opus 4.5 in Claude Code.
Claude Opus 4.5 is now available in Claude Code for Pro users. Pro users can select Opus using the /model command in their terminal. — @claudeai on X
Important details
| Aspect | Detail |
|---|---|
| Command | /model opus |
| Consumption | Faster rate limits than Sonnet |
| Recommendation | Opus for complex tasks, Sonnet for the rest |
| Max Plans | 5x and 20x offer more Opus usage |
How to use
- Run
claude update - Launch
/model opus - Enjoy the power of Opus 4.5
Claude Code in Slack (Beta)
December 4, 2025 — Delegate coding tasks directly from Slack.
You can now delegate tasks to Claude Code directly from Slack. Simply tag @.Claude in a channel or thread. Coding tasks will automatically be routed to Claude Code. — @claudeai on X
How it works
| Aspect | Detail |
|---|---|
| Activation | Tag @.Claude in Slack |
| Routing | Tasks automatically sent to Claude Code |
| Session | New web session created |
| Availability | Beta for Team and Enterprise |
Use cases
- Code review requested in a Slack thread
- Urgent bug fixes from a conversation
- Refactoring launched during a meeting
- Documentation generated following a discussion
Slack integration makes Claude Code accessible without leaving your main communication tool.
Claude Agent SDK: Major updates
December 5-6, 2025 — Three important improvements for building custom agents.
We’ve shipped three new updates for Claude Agent SDK: Support for 1M context windows, Sandboxing, and V2 of our TypeScript interface. — @claudeai on X
What’s new
| Feature | Description |
|---|---|
| 1M Context | Use Sonnet 4.5 with 1M tokens for data-intensive agents |
| Sandboxing | Filesystem and network isolation for production agents |
| TypeScript V2 | Simplified interface: send(), receive(), done |
Simplified TypeScript Interface
The old interface with async generators and yield coordination is replaced by a simpler model:
- send() — Send a message
- receive() — Receive the response
- done — Check for completion
Multi-turn conversations become a simple send() call.
Async Subagents and new commands
December 9, 2025 — Four new features for Claude Code CLI.
We’re releasing more upgrades to Claude Code CLI: Async subagents, Instant compact, Custom session names, Usage stats. — @claudeai on X
Async Subagents
Tasks can now spawn async subagents that:
- Continue in the background even if the main agent finishes
- Handle long tasks like log monitoring
- Wait for builds without blocking the main workflow
Instant Compact
Context compaction is now exponentially faster — seconds instead of minutes.
⚠️ Note: This feature was temporarily disabled following frequent summarization issues.
Session Names (/rename)
| Command | Action |
|---|---|
/rename | Give a custom name to a session |
R in /resume | Shortcut to rename |
P in /resume | Preview a session |
Usage Stats (/stats)
The new /stats command generates:
- Visualization of daily usage
- Data on sessions
- Usage streaks
- Favorite models
Claude Code on Android (Research Preview)
December 11, 2025 — Anthropic announces a preview of Claude Code directly from the Android app.
Claude Code is now available as a research preview on Android! Launch agentic cloud coding tasks from your phone. — @claudeai on X
How it works
| Aspect | Detail |
|---|---|
| Type | Research preview (experimental) |
| Execution | Background cloud tasks |
| Usage | Launch coding tasks from phone |
| Advantage | Code on the go, without a computer |
Use cases
- Launch a long task before leaving the office
- Check progress of a build or deployment
- Quick fixes from anywhere
- Code review on the go
This preview marks an important step: Claude Code is no longer limited to the desktop terminal.
Hotkey Model Switcher
December 11, 2025 — New feature to switch models on the fly.
Quickly switch models mid-prompt using a new hotkey for model selection. Speed up your workflow by choosing the right model for each task. — @claudeai on X
Why it’s useful
| Model | When to use it |
|---|---|
| Haiku 4.5 | Quick tasks, simple refactoring |
| Sonnet 4.5 | Performance/cost balance |
| Opus 4.5 | Complex tasks, architecture |
Optimized workflow
- Start with Haiku for simple tasks
- Switch to Sonnet for main code
- Switch to Opus for architectural decisions
No need to restart a session to change models!
Context Window in the Status Line
December 11, 2025 — Visibility on context usage directly in the interface.
Context window information is now visible in Claude Code’s status line. Stay informed about your context usage as you work. — @claudeai on X
What is displayed
| Info | Description |
|---|---|
| Tokens used | How much context is consumed |
| Remaining capacity | Available space before compaction |
| Visual indicator | Context progress bar |
Advantages
- Anticipate automatic compactions
- Optimize long prompts
- Manage complex sessions with many files
Syntax Highlighting in Diffs
December 16, 2025 — Code diffs now benefit from syntax highlighting.
Syntax highlighting in diffs makes it easier to scan through code changes. See exactly what Claude changed with better visual clarity. — @claudeai on X
Before vs After
| Before | After |
|---|---|
| Raw green/red text | Code colored by language |
| Hard to scan | Natural reading |
| Changes barely visible | Obvious modifications |
Impact on workflow
- Faster review of proposed changes
- Easier detection of syntax errors
- Better understanding of modified code
Prompt Suggestions
December 16, 2025 — Claude now suggests the next prompt after each task.
After completing a task, Claude now suggests what you might want to do next. Discover new possibilities and keep your momentum going. — @claudeai on X
How it works
After completing a task, Claude offers contextual suggestions:
- After a bug fix → “Do you want to add a test for this case?”
- After a new feature → “Do you want to update the documentation?”
- After a refactoring → “Do you want to check existing tests?”
Advantages
| Benefit | Description |
|---|---|
| Productivity | Chain tasks without thinking |
| Best practices | Automatic reminders (tests, docs) |
| Discovery | New possibilities suggested |
Plugins Marketplace
December 16, 2025 — Launch of the official Claude Code plugins marketplace.
Introducing the Claude Code plugins marketplace. Discover and install first-party plugins to extend Claude’s capabilities. — @claudeai on X
What the marketplace brings
| Aspect | Detail |
|---|---|
| Discovery | Browse available plugins |
| Installation | In one click from Claude Code |
| First-party | Official Anthropic plugins |
| Quality | Verified and maintained |
Available plugins
The marketplace offers plugins for:
- Integrations — GitHub, GitLab, Jira
- Testing — Automated testing frameworks
- Deployment — CI/CD, cloud providers
- Documentation — Automatic generation
Create your own plugins
The plugin system is open. The official documentation explains how to create and publish your own extensions.
Guest Passes for Max
December 16, 2025 — Max subscribers can now share Claude with their loved ones.
Max subscribers now get 3 guest passes to share Claude with friends and family. Each pass gives 1 week of Pro access. Use /passes in Claude to send them. — @claudeai on X
Program details
| Aspect | Detail |
|---|---|
| Number | 3 passes per Max subscriber |
| Duration | 1 week of Pro access each |
| Command | /passes in Claude |
| Target | Friends and family |
How to use
- Open Claude (web or app)
- Type
/passes - Send the invitation link
- The recipient has 1 free Pro week
Why it’s interesting
- Discovery — Let your circle try Claude
- Conversion — Guests can subscribe afterwards
- Added value — Bonus for Max subscribers
Version recap
| Date | Main features |
|---|---|
| Nov 27 | Opus 4.5 for Pro users |
| Dec 4 | Claude Code in Slack (beta) |
| Dec 5-6 | Agent SDK: 1M context, sandboxing, TypeScript V2 |
| Dec 9 | Async subagents, instant compact, /rename, /stats |
| Dec 11 | Android preview, hotkey switcher, context status |
| Dec 16 | Syntax highlighting, prompt suggestions, plugins, guest passes |
What this means for developers
December 2025 marks a major evolution for Claude Code:
- Integration — Slack, improved Agent SDK
- Autonomy — Async subagents for long tasks
- Mobility — Android preview to code everywhere
- Flexibility — Switch model according to task
- Productivity — Readable diffs, contextual suggestions
- Extensibility — Official plugins marketplace
Claude Code continues to establish itself as the reference tool for AI-assisted development.