The agent guardrail

Agents write plausible UI with made-up values: #3b82f6 instead of var(--color-primary), gap: 14px instead of var(--space-3), or a fabricated var(--color-primary-500) that doesn’t exist in your system. dscheck closes the loop: after every file the agent writes, it reports each off-system value with the exact replacement, and the agent fixes itself before you ever see the diff.

Claude Code

Copy the hook from integrations/claude-code/ into your project’s .claude/settings.json:

{
  "hooks": {
    "PostToolUse": [
      {
        "matcher": "Edit|Write",
        "hooks": [{ "type": "command", "command": "sh .claude/dscheck-hook.sh" }]
      }
    ]
  }
}

The hook lints only the file that was written and exits 2 with the findings on stderr — Claude Code feeds that back to the agent, which applies the fix field of each finding.

Any agent: the agent format

dscheck check src/Button.tsx --format agent

One JSON line per finding, suggestion first, so a model can act without prose parsing:

{"fix":"var(--spacing-3)","rule":"dscheck/no-raw-length","file":"src/Button.tsx","line":19,"col":16,"message":"Raw length 14px in padding — use var(--spacing-3) (12px, Δ2px)"}

Measured effect

Same component task, same model, same design system:

	off-system values in the diff
agent without guardrail	19 (10 raw colors, 9 raw lengths)
agent with dscheck hook	0

The guardrailed agent consulted dscheck tokens first and shipped on-system in one pass.