Glossary

A tree representation of source code structure. Claude Code uses tree-sitter to parse shell commands into ASTs for security analysis — detecting dangerous patterns like command injection or path traversal.

A function that can yield multiple values over time asynchronously. In Claude Code, async generators power all streaming data flows — from API responses to tool execution results. They enable real-time UI updates and natural backpressure.

The maximum amount of text an AI model can process in a single request. When conversations exceed this limit, Claude Code uses compaction strategies to summarize older messages while preserving important context.

A mechanism to enable or disable features without deploying new code. Claude Code uses feature('FLAG_NAME') to gate features by user type, environment, or percentage. Disabled code is eliminated by the bundler.

A React renderer for the terminal. Instead of rendering to HTML DOM (like web React), Ink renders React components as terminal text with colors, layouts, and interactive elements using ANSI escape codes.

A standard protocol for connecting AI models to external tools and data sources. Like USB-C for AI — any MCP-compatible server can expose tools, resources, and prompts that Claude can discover and use automatically.

The part of React that figures out what changed and updates the output. The browser uses react-dom; Claude Code uses a custom Ink reconciler that maps React operations to terminal output instead of DOM nodes.

An independent Claude instance spawned by the main agent to handle a specific subtask. Each sub-agent has its own conversation context, tools, and can run in the foreground (blocking) or background (async notification).

The system that manages how Claude's tool calls are executed. Read-only tools (Glob, Grep, Read) run in parallel for speed; write tools (Edit, Write, Bash) run serially to prevent race conditions.

A persistent, bidirectional communication protocol. Claude Code's IDE bridge uses WebSocket to maintain a real-time connection between the CLI process and VS Code, enabling instant sync of messages, permissions, and file changes.

Facebook's cross-platform Flexbox layout engine. In Claude Code, Yoga computes the exact pixel positions of terminal UI elements — enabling proper flex, padding, margin, and absolute positioning in a text-based environment.

A TypeScript-first runtime type validation library. Claude Code uses Zod schemas to validate tool inputs — every tool defines its expected parameters as a Zod schema, which is automatically converted to JSON Schema for the API.