Overview
Claude Code is an AI programming tool launched by Anthropic that can read codebases, edit files, run commands, and integrate with development tools. It now supports terminals, IDE extensions, desktop applications, and browser interfaces, not just command-line tools. Unlike IDE plugins, Claude Code uses the command line as its core interface, making it more suitable for system-level development and the workflow of backend engineers.
2026/5/28: The flagship model was upgraded to Claude Opus 4.8, surpassing GPT-5.5 in programming and agent task capabilities. 2026/6/30 filled a critical gap—Claude Sonnet 5 simultaneously landed in Claude Code, positioned as "thinking ability close to Opus 4.8 + Sonnet-level execution speed," and is called the long-missing "best executor" of Claude Code: Opus 4.8 handles complex planning and reasoning, while Sonnet 5 handles high-frequency, low-cost execution, and their combination significantly reduces the overall cost of long tasks. Anthropic officially launched the Claude Code Plugin Directory on GitHub, building a high-quality AI programming extension ecosystem; the enterprise version introduced Managed Agents self-hosted sandbox (paired with Project Glasswing).
2026/10/8: Claude Code shipped v2.1.293, adding Claude Haiku 5.5 and making it the default Haiku model on the Anthropic API, with 1M context support at $0.10 per million input and $0.50 per million output tokens, rising to $0.50 and $2.50 for prompts over 100K tokens, plus a large batch of fixes.
Cloud sessions and hosted projects: On 2026/10/6, Claude Code introduced cloud sessions, where each task runs on its own VM with the repository cloned to a fresh branch. Sessions can be started and tracked from claude.ai/code, phone, desktop, terminal and Slack, and finish with a branch ready to turn into a pull request, at no extra charge on Pro, Max, Team and Enterprise plans. Cloud sessions left the research preview and became generally available on 2026/9/23, running on Anthropic-managed infrastructure so work continues after a laptop is closed; existing subscribers could claim a one-time credit before October 7, $100 for Pro and $250 for Max, granted on top of plan limits and expiring November 4, with the credit consumed by cloud sessions first before falling back to normal usage. On 2026/9/17, Anthropic redesigned Projects in Claude Code, moving from folder-based organisation to projects organised around conversation: the user sets a goal, and Claude breaks down the work, schedules several threads in parallel, reviews each thread output and consolidates the result, with every thread in effect its own branched Claude Code cloud session.
Customization and ecosystem: Claude Code introduced mods on 2026/10/2—JavaScript or TypeScript modules running as hooks inside a plugin that modify model behavior, customize the UI, and replace built-in functionality, and can also observe, rewrite, or reject events. A mod takes a few lines of TypeScript, ships with plugins, and installs via /plugin in the CLI or desktop app, requiring Claude Code 2.1.287 or later.
Usage limits: Anthropic's Claude Code limit change took effect on 2026/9/14: the temporary 50% weekly usage bonus that began on May 13, 2026 expired, while the standard weekly allowance was permanently raised by 25% at unchanged subscription prices. In the same round, five-hour session limits for Pro, Max, Team and per-seat Enterprise were previously doubled permanently and weekday peak throttling was removed.
The core advantage of Claude Code is based on Claude's powerful code understanding ability, combined with direct terminal operation permissions, enabling file-level code refactoring, multi-file modifications, and complex development tasks.
Key Features
- Multi-platform Support: Available in terminal, IDE extensions, desktop applications, and browser
- File Read/Write Permissions: AI can directly read and modify your code files
- Command Execution: Can execute shell commands, run tests, and install dependencies
- Codebase Understanding: Able to understand the code structure and dependency relationships of the entire project
- Multi-file Refactoring: Modify multiple files in a single conversation, handling cross-file dependencies
- Git Integration: Understands git history, can commit code and create branches
- Cloud Sessions: Each task runs on its own VM with the repository cloned to a fresh branch; sessions can be started and tracked from claude.ai/code, phone, desktop, terminal and Slack, and finish with a branch ready to turn into a pull request
- Conversational Projects: Projects are organised around conversation: the user sets a goal, and Claude breaks down the work, schedules several threads in parallel, reviews each thread output and consolidates the result
- Mods: JavaScript or TypeScript modules running as hooks inside a plugin that modify model behavior, customize the UI, and replace built-in functionality, and can also observe, rewrite, or reject events; install via /plugin in the CLI or desktop app
Use Cases
- Terminal programming for backend and system developers
- Refactoring and modifying large codebases
- Automation of DevOps and operations tasks
- Experienced developers who prefer command-line workflows
- Automated code modification in CI/CD pipelines
- Running long tasks on Anthropic-managed infrastructure that continue after a laptop is closed
- Scheduling and reviewing parallel work threads within a conversational project
Pros
- Multi-platform support: available on terminal, IDE, desktop, and browser
- Claude's code ability: the underlying model performs top-tier in programming
- Broad operational permissions: can directly read/write files and execute commands
- Strong multi-file operations: performs well in complex refactoring scenarios
- No IDE lock-in: usable in any terminal environment
- Cloud sessions run on Anthropic-managed infrastructure and are available at no extra charge on Pro, Max, Team and Enterprise plans
- Mods allow JavaScript or TypeScript modules to modify model behavior, customize the UI, and replace built-in functionality
Pricing
Claude Code is free to install, but requires a Claude subscription or an Anthropic Console account to use. The terminal CLI and VS Code also support third-party providers. Cloud sessions are available at no extra charge on Pro, Max, Team and Enterprise plans, and existing subscribers could claim a one-time credit before October 7, $100 for Pro and $250 for Max, granted on top of plan limits and expiring November 4. Claude Haiku 5.5, the default Haiku model on the Anthropic API as of v2.1.293, is priced at $0.10 per million input and $0.50 per million output tokens, rising to $0.50 and $2.50 for prompts over 100K tokens.
Summary
Claude Code is a terminal-centric AI programming tool suitable for backend engineers, system-level developers, and DevOps professionals. Its core strengths lie in its powerful codebase understanding, direct file read/write and command execution capabilities, as well as multi-file refactoring abilities. The underlying models (Claude Opus 4.8 and Sonnet 5, with Claude Haiku 5.5 added as the default Haiku model on the Anthropic API in v2.1.293) deliver top-tier performance on programming tasks, support multiple platforms (terminal, IDE, desktop, browser), and do not lock users into a specific development environment. Cloud sessions, generally available since 2026/9/23, run each task on its own VM with the repository cloned to a fresh branch and can be started and tracked from claude.ai/code, phone, desktop, terminal and Slack, while Projects now organise work around conversation with parallel threads. Mods, introduced 2026/10/2, let JavaScript or TypeScript modules run as hooks inside a plugin to modify model behavior, customize the UI, and replace built-in functionality.
Version History
- Releases v2.1.306 through v2.1.308 (2026-10-22): v2.1.306 fixes a false not-logged-in error when starting a cloud session without environment variables, and stops API errors from being replaced by a prompt-too-long message in sessions with many MCP tools. v2.1.307 adds the /claude-api command for migrating to API version 2026-10-21 and emits a safety event for each tool call. v2.1.308 focuses on bug fixes and reliability.
- v2.1.309 fixes sandbox and permission issues (2026-10-22): Claude Code v2.1.309 fixes sandboxed Bash commands loading shell startup files outside the sandbox before each command on macOS and Linux, and corrects macOS sandbox denyWrite glob patterns not applying through symlinks.
- CLI and desktop update together: idle compaction, a sessions hub and parallel sessions (2026-10-14): On October 14, 2026, Anthropic shipped a batch of Claude Code updates. On the CLI side, idle sessions now compact automatically, saving a context summary before the prompt cache expires and resuming from that summary; idleCompaction can turn it off and tune the threshold. Version 2.1.299 shipped alongside. On the desktop app, parallel sessions got a rework with a new sessions hub and sidebar session management, live session status in the navigation bar, environment saving and nested sessions, plus proactive suggestions for follow-up work and one-click new sessions. Cloud sessions can be started from a phone and run alongside other sessions.
- Claude Code Projects is now available to all Pro and Max users. (2026-10-10): Anthropic announced that all Pro and Max users on the waitlist have gained access to Claude Code Projects. Projects are described as an ongoing conversation coordinated by Claude, with each task running in parallel as an independent thread. Official introductory videos are also provided to help new users get started.
- Claude Code v2.1.296 ships and Projects opens to all Pro and Max users (2026-10-09): Claude Code released v2.1.296, adding a code key to managed.policies[] for the Claude apps gateway and enabling gateway mode in the Code tab of Claude Desktop. Claude Code Projects also opened to every Pro and Max user on the waitlist, with a four-minute getting-started video.
- v2.1.293 (2026-10-08): Claude Code shipped v2.1.293, adding Claude Haiku 5.5 and making it the default Haiku model on the Anthropic API, with 1M context support at $0.10 per million input and $0.50 per million output tokens, rising to $0.50 and $2.50 for prompts over 100K tokens, plus a large batch of fixes
- Cloud sessions (2026-10-06): Claude Code introduced cloud sessions, where each task runs on its own VM with the repository cloned to a fresh branch. Sessions can be started and tracked from claude.ai/code, phone, desktop, terminal and Slack, and finish with a branch ready to turn into a pull request, at no extra charge on Pro, Max, Team and Enterprise plans
- Mods customization (2026-10-02): Claude Code introduced mods: JavaScript or TypeScript modules running as hooks inside a plugin that modify model behavior, customize the UI, and replace built-in functionality, and can also observe, rewrite, or reject events. A mod takes a few lines of TypeScript, ships with plugins, and installs via /plugin in the CLI or desktop app, requiring Claude Code 2.1.287 or later
- Cloud sessions leave research preview, with one-time credits for Pro and Max (2026-09-24): Claude Code cloud sessions became generally available after the research preview, running on Anthropic-managed infrastructure so work continues after a laptop is closed. Existing subscribers can claim a one-time credit before October 7, $100 for Pro and $250 for Max, granted on top of plan limits and expiring November 4. The team later clarified that the feature still runs inside Pro or Max subscriptions, with the credit consumed by cloud sessions first before falling back to normal usage.
- Claude Code cloud sessions become generally available, with one-time credits for Pro and Max subscribers (2026-09-23): Cloud sessions left the research preview and are now generally available, so tasks keep running on Anthropic-hosted infrastructure after the laptop lid closes. Existing subscribers can claim a one-time credit of 100 dollars on Pro and 250 dollars on Max, separate from plan usage limits and available until October 7.
- Projects redesigned: from folder to a hosted multi-threaded conversational project (2026-09-17): Anthropic redesigned Projects in Claude Code, moving from folder-based organisation to projects organised around conversation. The user sets a goal, and Claude breaks down the work, schedules several threads in parallel, reviews each thread output and consolidates the result; every thread is in effect its own branched Claude Code cloud session. The change points at multi-threaded hosting: a project is no longer just a collection of files but a work unit that can be scheduled and reviewed.
- Anthropic rebuilds its test impact analysis service to absorb agentic coding CI load (2026-09-14): Anthropic detailed an internal engineering effort: with Claude writing roughly 80% of the code, CI job volume grew about 25x in six months, overwhelming the existing test impact analysis service. The team redesigned how test sets are selected based on the blast radius of a change, added finer sharding and queue scheduling to cut pipeline wait times, and kept rollback safety nets in place. The post covers the causes of queue backlog and before-and-after numbers.
- Claude Code weekly limit change takes effect: temporary bonus expires, standard weekly allowance permanently up 25% (2026-09-14): Anthropic's Claude Code limit change took effect on September 14, 2026: the temporary 50% weekly usage bonus that began on May 13, 2026 expired, while the standard weekly allowance was permanently raised by 25% at unchanged subscription prices. Compared with the promotional period, heavy users see about 17% less usable capacity, though still a quarter more than the original baseline. In the same round, five-hour session limits for Pro, Max, Team and per-seat Enterprise were previously doubled permanently and weekday peak throttling was removed.