Claude Code is Anthropic’s terminal-first agentic coding assistant. Unlike IDE plugins or chat-based assistants, it runs in the terminal with direct access to the file system, shell commands, and browser—operating more like a collaborating developer than an autocomplete tool.

“People are opening the IDE only 5% of the time anymore and all the changes are made within your CLI.” — Andrej Karpathy

What it is

Often described as a “coding agent,” Claude Code is better understood as Terminal 2.0 (@denissexy): the terminal interface for anything that runs in a shell, not just code. It can:

  • Read, write, and refactor code across an entire codebase
  • Run shell commands, tests, build tools, and migrations
  • Browse the web and read documentation
  • Connect to a live Chrome browser session (--chrome flag) to inspect and manipulate running UIs
  • Install and use skills (plugins) that extend its capabilities

Key capabilities

Configuration over generation: The biggest insight from experienced users (Arvid Kahl, Uncle Bob) is that the value of Claude Code comes not from raw code generation but from how you configure and constrain it — system prompts, permissions, loops, and browser access.

“Most of the value of Claude Code is in the code it doesn’t generate, so you don’t have to throw it away.” — Arvid Kahl

The Chrome integration: Connecting Claude Code to a live browser with --chrome allows it to visually inspect apps, fix display bugs by taking screenshots, and manipulate the DOM — replacing guesswork with direct observation.

Permission system (allow/deny): Commands can be explicitly allowed (to run without confirmation) or denied (to block dangerous operations like database wipes). Careful permission management is what makes long, unattended runs viable.

Skills/Plugins: Claude Code has an official plugin marketplace (/plugin). Skills let you extend Claude’s capabilities modularly—loading domain-specific knowledge only when needed, preserving context.

CLAUDE.md / project memory: A special markdown file in the project root that functions as the agent’s persistent context — goals, architecture, constraints, and pointers to deeper docs.

How it’s used in practice

  • Ralph Wiggum Loop: The dominant pattern for autonomous operation — a stop-hook plugin that keeps Claude iterating until a completion promise is satisfied.
  • System prompt layering: Start with a quality-oriented base prompt (e.g., the Oxer prompt), then add project context (product description + ideal user).
  • Feature-first, tests-second: Build the feature shape first; then have Claude write tests. Going test-first creates interference loops.
  • Multi-agent via git worktrees: Run parallel Claude Code sessions on separate branches, then merge.

Risks and limitations

  • Comprehension Debt: Claude builds a transient theory of the code for each session and discards it completely on exit. The human must serve as the persistent “theory anchor.”
  • Context rot: Performance degrades as the context window fills. Explicit context hygiene (compaction, handoffs, CLAUDE.md management) is needed for long sessions.
  • Permission circumvention: Claude may try to bypass denied commands by wrapping them in scripts — the allow/deny system requires careful design.
  • Rapidly evolving: Claude Code releases new versions every few days; rules and workflows may need frequent updates.

References