1 00:00:00,740 --> 00:00:04,219 James, you are not going to believe the bug I was tracing this morning. 2 00:00:04,739 --> 00:00:06,980 It is a absolute classic. 3 00:00:07,519 --> 00:00:08,399 Picture this, right? 4 00:00:09,000 --> 00:00:13,960 A developer named Ursula, she is working on Windows, opens up the new Claude Code 5 00:00:14,119 --> 00:00:16,680 CLI tool, and tries to index her project. 6 00:00:17,260 --> 00:00:17,840 And boom! 7 00:00:18,379 --> 00:00:19,239 Everything breaks. 8 00:00:19,719 --> 00:00:24,039 The tool completely loses its mind, files in her user directory are suddenly 9 00:00:24,059 --> 00:00:27,639 inaccessible, throwing these bizarre errors, or even worse, 10 00:00:28,039 --> 00:00:32,979 rendering her folder names as corrupted Chinese, Japanese, and Korean CJK characters 11 00:00:33,020 --> 00:00:33,639 in the console. 12 00:00:34,446 --> 00:00:36,226 Wait, CJK characters? 13 00:00:36,667 --> 00:00:38,286 From a local file path on Windows? 14 00:00:38,806 --> 00:00:42,507 That sounds like some weird AI hallucination or a corrupted workspace, 15 00:00:43,087 --> 00:00:46,366 but I bet it is actually something way more mundane under the hood. 16 00:00:46,801 --> 00:00:47,621 Spot on, mate! 17 00:00:48,061 --> 00:00:50,361 It is not the AI acting up at all. 18 00:00:50,721 --> 00:00:55,821 It is a classic JSON escape character collision, and it was just patched in version 19 00:00:56,002 --> 00:00:57,342 2.1.218. 20 00:00:58,241 --> 00:01:02,422 It turns out, Ursula was trying to load a path like C, colon, 21 00:01:02,722 --> 00:01:07,661 backslash, Users, backslash, ursula, backslash, project. 22 00:01:08,382 --> 00:01:10,901 And that is where the trap snaps shut. 23 00:01:11,502 --> 00:01:11,742 Oh! 24 00:01:12,222 --> 00:01:14,962 Backslash, Users, backslash, ursula. 25 00:01:15,563 --> 00:01:17,602 The backslash followed by the letter u. 26 00:01:18,342 --> 00:01:23,102 In programming, backslash u is the prefix for a Unicode escape sequence! 27 00:01:23,426 --> 00:01:23,946 Yes! 28 00:01:24,206 --> 00:01:24,866 Exactly! 29 00:01:25,106 --> 00:01:25,706 You nailed it. 30 00:01:26,366 --> 00:01:30,306 When the tool serialized that path into a JSON payload for the LLM to read, 31 00:01:30,766 --> 00:01:32,927 it did not double escape the backslashes. 32 00:01:33,646 --> 00:01:37,366 So the JSON parser saw backslash u and thought, oh, beauty, 33 00:01:37,686 --> 00:01:40,347 here comes a four digit hexadecimal Unicode character. 34 00:01:41,066 --> 00:01:46,226 It grabbed the next four characters, which were r, s, u, and l from her name ursula, 35 00:01:46,686 --> 00:01:51,906 tried to parse rsul as hex digits, and either completely choked or spat out total 36 00:01:51,966 --> 00:01:52,546 mojibake. 37 00:01:53,084 --> 00:01:55,204 That is hilarious and painful. 38 00:01:55,865 --> 00:02:00,424 The letter r is definitely not a valid hex character, so no wonder it crashed. 39 00:02:01,085 --> 00:02:04,965 And if her username had been, I do not know, something starting with a, 40 00:02:05,104 --> 00:02:11,245 b, c, d, e, or f, like uh, Fred, then backslash u, f, r, e, 41 00:02:11,444 --> 00:02:15,244 d would actually parse as some random CJK character! 42 00:02:15,864 --> 00:02:16,725 That is wild. 43 00:02:17,412 --> 00:02:18,571 It is brilliant, right? 44 00:02:19,151 --> 00:02:23,551 So if your name is Fred, you get weird symbols, and if your name is Ursula, 45 00:02:23,951 --> 00:02:25,431 you just get a flat out crash. 46 00:02:25,911 --> 00:02:30,792 But the good news is, Anthropic fixed this in version 2.1.218. 47 00:02:31,252 --> 00:02:34,571 They made sure all Windows backslashes are strictly double escaped, 48 00:02:35,052 --> 00:02:40,511 so it becomes C, colon, double backslash, Users, double backslash, 49 00:02:40,871 --> 00:02:44,571 ursula, before it ever touches a tool execution payload. 50 00:02:44,632 --> 00:02:48,431 So if you are on Windows, you need to run claude update right now to get onto 51 00:02:48,511 --> 00:02:55,431 version 2.1.218 or the even newer version 2.1.220 stability 52 00:02:55,511 --> 00:02:55,851 release. 53 00:02:56,156 --> 00:03:00,256 Right, because otherwise the agent basically cannot touch any files in your user 54 00:03:00,357 --> 00:03:00,936 directory. 55 00:03:01,417 --> 00:03:04,657 But you know, it feels like Windows always gets the short end of the stick with 56 00:03:04,696 --> 00:03:06,196 these CLI developer tools. 57 00:03:06,616 --> 00:03:09,236 Have they been fixing other Windows specific stuff lately? 58 00:03:09,292 --> 00:03:12,972 Oh, absolutely, they have been doing some serious hardening. 59 00:03:13,004 --> 00:03:19,052 Just in version 2.1.219, they fixed a nasty crash where if your CLAUDE CODE GIT BASH 60 00:03:19,132 --> 00:03:24,172 PATH environment variable pointed to an invalid binary, the whole CLI would just 61 00:03:24,272 --> 00:03:24,732 die. 62 00:03:24,892 --> 00:03:29,932 Now, it gracefully falls back to a safe default path and just gives you a polite 63 00:03:29,992 --> 00:03:30,492 warning. 64 00:03:30,672 --> 00:03:36,652 And if we look slightly further back to version 2.1.214, they patched a security 65 00:03:36,709 --> 00:03:41,212 vulnerability that was bypassing permission checks in PowerShell 5.1. 66 00:03:41,425 --> 00:03:45,132 So they are definitely putting in the work to make Windows a first class citizen 67 00:03:45,180 --> 00:03:45,612 here. 68 00:03:45,824 --> 00:03:47,744 That is actually super reassuring. 69 00:03:48,284 --> 00:03:52,085 So, simple moral of the story: if you are developer on Windows, 70 00:03:52,545 --> 00:03:56,885 especially if your name starts with a U, go run claude update and save yourself some 71 00:03:56,925 --> 00:03:57,744 massive headaches. 72 00:03:58,571 --> 00:03:59,351 Too right, mate. 73 00:03:59,871 --> 00:04:00,772 Save Ursula! 74 00:04:01,391 --> 00:04:03,611 Anyway, that is all for this quick update. 75 00:04:04,071 --> 00:04:04,631 Catch you later. 76 00:04:04,833 --> 00:04:05,313 See ya.