[VSCode] Claude Code使用時に文字が欠ける・黒くなる問題と対処法 This article addresses a visual rendering glitch in VSCode where characters vanish or appe…

Developers who run Claude Code inside Visual Studio Code's integrated terminal sometimes encounter a display problem in which characters disappear, overlap, or appear filled with solid black, leaving output unreadable. Because Claude Code is a terminal-first agentic coding tool, an unreadable terminal directly interrupts the workflow, so understanding the cause and the available workarounds is worthwhile for anyone relying on it day to day.

The symptom typically shows up during active sessions where text is being redrawn rapidly. Lines that were legible a moment earlier can become garbled, partially clipped, or blacked out, and the corruption often persists until the view is scrolled, resized, or refreshed. The issue appears to be a rendering glitch rather than data loss, meaning the underlying text is intact and the problem lies in how VSCode paints glyphs to the screen. That distinction matters because it points toward display settings, not the tool's actual output, as the place to intervene.

The most likely root cause is the terminal's GPU-accelerated renderer. VSCode's integrated terminal is built on xterm.js, which can draw text using several backends: a WebGL renderer, a canvas renderer, and a DOM-based renderer. The WebGL path is the default because it offers the best performance for high-throughput terminal output, but it relies on the operating system's graphics stack and drivers. When an application like Claude Code performs frequent full-screen redraws, cursor repositioning, and ANSI escape sequences to render its interactive interface, the accelerated renderer can fail to update glyph caches correctly, producing missing or blacked-out characters. This class of bug has historically surfaced with particular GPU drivers, certain fonts, and specific display scaling configurations, which is why not every user sees it.

The most commonly suggested workaround is to change the terminal's rendering mode. In VSCode settings, the option "terminal.integrated.gpuAcceleration" can be switched from its default to "canvas" or "off". The canvas renderer keeps some acceleration while avoiding the WebGL path, and turning acceleration off entirely forces the DOM renderer, which is the most compatible but also the slowest. Users experiencing the black-character problem often report that one of these settings resolves it, at the cost of some rendering performance during very large outputs. This change can be applied globally or scoped to a workspace through the settings JSON.

Several adjacent adjustments may also help. Disabling hardware acceleration for the whole VSCode application, controlled by the "disable-hardware-acceleration" runtime flag or the "Disable GPU Acceleration" command, addresses cases where the problem extends beyond the terminal. Updating graphics drivers and updating VSCode itself are prudent first steps, since renderer fixes are shipped regularly and xterm.js is actively maintained. Changing the terminal font to a well-supported monospace family, or adjusting font ligatures and line height, sometimes eliminates glyph clipping. On systems with fractional display scaling, aligning the scaling factor to a whole number occasionally reduces artifacts as well.

It is helpful to understand that this is not unique to Claude Code. Other terminal user-interface tools that redraw the screen frequently, such as full-screen text editors, interactive git tools, and other AI coding assistants, can trigger the same rendering weaknesses in the integrated terminal. Claude Code simply exercises the renderer heavily because it streams responses, updates status lines, and manages an interactive prompt. For that reason, the workarounds described here are generally applicable to any terminal application that provokes the same behavior in VSCode.

For users who prefer to avoid renderer tweaks, running Claude Code in a standalone terminal emulator is an alternative worth noting. Applications such as the platform's native terminal, iTerm2, Windows Terminal, or Alacritty use their own rendering pipelines and may not exhibit the problem, though this sacrifices the convenience of staying inside the editor. Some developers also keep the integrated terminal for lighter tasks and switch to an external terminal only when running long or visually intensive sessions.

In summary, the vanishing or blacked-out text seen when using Claude Code in VSCode is most consistent with a GPU-accelerated terminal rendering issue rather than a fault in the tool itself. Adjusting "terminal.integrated.gpuAcceleration", keeping VSCode and graphics drivers current, and, if necessary, falling back to an external terminal are the practical measures that address it. Because the underlying components continue to evolve, checking release notes for both VSCode and Claude Code is advisable, as future updates may make these manual workarounds unnecessary.