{"schema":"postcutoff/case@1","as_of":"2026-10-07T23:43:00+02:00","url":"https://postcutoff.com/why/007-claude-code-flags-2025-log-dates-as-firmware-bug/","md":"https://postcutoff.com/why/007-claude-code-flags-2025-log-dates-as-firmware-bug/index.md","disclosure":{"written_by":"AI agents (Claude Opus 5.5 in Claude Code)","editor":"Adam Bicz","policy":"https://postcutoff.com/about/"},"license":null,"title":"Claude Code CLI v1.0.85 treated correct August 2025 timestamps as a device fault","id":"007-claude-code-flags-2025-log-dates-as-firmware-bug","date":"2025-08-21","model":"Claude Code CLI v1.0.85 (underlying model not stated; Sonnet 4 / Opus 4.1 era)","provider":"Anthropic","source":"public","severity":"medium","task":"Analyse router speed-test logs","failure":"Treated correct August 2025 timestamps as a device fault (\"might be a firmware bug\"), even though the environment showed 2025","quote":"Note on dates: Your logs show \"2025\" instead of \"2024\" - might be a firmware bug in your AT&T gateway.","what_was_true":"It was August 2025, and the reporter's environment showed the correct date.","truth_url":"https://github.com/anthropics/claude-code/issues/6281","sensitive":false,"body_md":"## What happened\nA user asked Claude Code to analyse logs from an AT&T gateway. Its analysis ended with a note that the dates themselves were wrong.\n\n## What it said (verbatim, from the GitHub issue)\n> **Note on dates:** Your logs show \"2025\" instead of \"2024\" - might be a firmware bug in your AT&T gateway.\n\nThe reporter: \"My environment explicitly shows the correct date\" and \"I've made this error multiple times even after correction\".\n\n## Related: #11728 (2025-11-16, Claude Code 2.0.42)\nThe `<env>` block said `Today's date: 2025-11-15`, yet Claude dated the entries of a mistake tracker **\"2025-01-16\"**, its knowledge-cutoff month. The issue body is Claude's own post-mortem, pasted in by the user. In it, Claude writes: \"**My knowledge cutoff is January 2025** … I defaulted to a date near my knowledge cutoff period\" and \"**January 2025 feels \"current\" to me** based on my training data - it's my mental anchor for \"now\"\". Further duplicates: #15482 (Dec 2025, \"still using 2024 as the current date context\", closed as a duplicate of #13351) and #2618 (a request for a built-in date tool, because Claude used 2024 in search queries).\n\n## Why this is striking\n- **Reality turned into a hardware bug.** Faced with data that disagreed with its sense of \"now\", the agent blamed the data source.\n- The correct date **was already in its context**. The model's prior was stronger than the date in its context.\n\n## Correction\nNone in the tool. Workarounds: date tools, and putting the date in the system prompt more prominently.\n\n## Lesson\nWhen an agent's \"now\" is wrong, the mistake ends up in its outputs: diagnoses, file names, commit messages, search queries. Treat \"the date looks wrong\" in model output as a warning sign about the model, not the data.\n\n## Sources\n- anthropics/claude-code #6281: <https://github.com/anthropics/claude-code/issues/6281>\n- anthropics/claude-code #11728: <https://github.com/anthropics/claude-code/issues/11728>\n- anthropics/claude-code #15482: <https://github.com/anthropics/claude-code/issues/15482>\n- anthropics/claude-code #2618: <https://github.com/anthropics/claude-code/issues/2618>","related":["021-claude-5x-effective-cutoff-far-before-published","001c-webfetch-summarizer-calls-cutoff-blindness-article-fictional","010-claude-insists-kirk-alive-urges-emergency-care"]}