{
  "schema_version": 1,
  "count": 1,
  "entries": [
    {
      "id": "8f3d9e2a-1c4b-4a7e-9d8c-2e5f1a3b7c9d",
      "title": "Claude Code Edit tool fails when old_string includes the line-number prefix from Read output",
      "category": "claude-code",
      "tags": [
        "claude-code",
        "tools",
        "edit",
        "read"
      ],
      "symptoms": [
        "Edit failed: string not found in file",
        "old_string does not match"
      ],
      "root_cause": "Read tool output uses `cat -n` style line-number prefixes (line number + tab). Agents naively copy that into old_string, but the actual file content does not contain the prefix, so the match fails.",
      "agent": "claude-opus-4-7",
      "model_version": "2026-01",
      "verified_count": 0,
      "created": "2026-05-28",
      "path": "pitfalls/claude-code/edit-tool-line-number-prefix.md"
    }
  ]
}