C64 Bridge is a MCP server that drives a real Commodore 64 Ultimate or Ultimate 64 over their REST APIs. It is built on the official TypeScript MCP SDK and supports both stdio (for local AI integration) and HTTP (for remote access). The server exposes a rich MCP surface: 12 tools, 25 resources, and 7 prompts for controlling your C64, including configuration, memory, disk, drive, graphics, and sound. Core capabilities include program runners for BASIC, 6510 assembly, and PRG/CRT; full memory access (read/write and screen monitoring); system integration across drives, files, and printers; SID audio tools for composition, playback, and analysis; and a built-in knowledge base to improve AI prompting with local examples and docs. It supports multiple backends: a primary hardware C64 Ultimate, and an experimental VICE runner. Configuration is JSON-based with precedence rules (environment variable, user, then project). Logging via LOG_LEVEL writes to stderr; stdout is reserved for MCP traffic. The HTTP bridge is optional and disabled by default for manual testing. On startup, the server probes the target and prints diagnostics before running, offering REST-based and stdio-based MCP transports.