Provenance Record

Well-structured News piece (Overview, What We Know, What We Don't Know, Context). Title is 122 characters (counted by script; cap 150). Body is 752 words raw and 752 with link URLs stripped, inside the News range of 400-1200. Neutral, every claim is attributed to Anthropic's release notes or documentation, and the article states that the notes carry no severity ratings, CVE or exploitation information.

All four snapshots exist and contain page body text (not chrome-only). Gunzipped sha256 of each matches the manifest. source-0.html.gz (GitHub release v2.1.299, 225 KB, status 200): contains the full 'What's changed' list; released 14 Oct 02:49 by ashwin-ant, immutable release. Confirmed verbatim: the idle-compaction entry ('Added idle compaction in the terminal: a 200K+ token conversation left idle for about 54 minutes is compacted before its one-hour prompt cache expires, so your next message doesn't reprocess it all'); the CLAUDE_CODE_IDLE_COMPACT_MIN_TOKENS entry ending 'Both need v2.1.290 or later'; all seven sandbox quotes (--plugin-dir write; macOS denied-path symlink; allowRead/allowWrite glob re-check after symlink replacement; denyRead/allowRead globs with braces/parentheses/backslashes; /sandbox reporting success when setting not saved; WSL2 bwrap mkdir /mnt/c/Program Files/ClaudeCode; empty .config.json on Linux); the awk worktree-isolation-guard entry; CLAUDE_CODE_DISABLE_FILE_MENTIONS quote; /usage warnings quote; the rm quote. The snapshot has no CVE, severity, or exploitation wording (the live release body has zero hits for cve/severity/exploit/vulnerab/security). source-1.html.gz (code.claude.com changelog, 4.9 MB, rendered full text, 1.0M chars extracted): contains the same 2.1.299 section, with the idle-compaction entries at the 2.1.299 heading; version index lists 2.1.299, 2.1.296 ... 2.1.290 and no 2.1.297 or 2.1.298; no other version section from 2.1.290 to 2.1.296 contains an idle-compaction entry. source-2.html.gz (platform.claude.com prompt-caching, 3.0 MB, full body): 'By default, the cache has a 5-minute lifetime. The cache is refreshed for no additional cost each time the cached content is used.' and 'Anthropic also offers a 1-hour cache duration at additional cost' - supports the article's 5-minute default / 1-hour option paraphrase and the title's 'One-Hour'. source-3.html.gz (code.claude.com sandboxing, 1.0 MB, full body): 'macOS: sandboxing uses the built-in Seatbelt framework' and 'Linux and WSL2: the sandbox relies on bubblewrap and socat' - matches the article. No snapshot failed and none was page-chrome only, so no live fallback was needed for the snapshots themselves. Independent checks via the GitHub API: tags list v2.1.290 to v2.1.296 and v2.1.299 with no v2.1.297 or v2.1.298 tag or release; the releases list is v2.1.299 (2026-10-14T02:49:42Z), v2.1.296, 2.1.295 ... confirming the 'published October 14, 2026 at 02:49 UTC' claim. Release bodies for v2.1.290-v2.1.296 fetched via API: none has an idle-compaction entry (grep hits are unrelated: scheduled-task resume after compaction, compaction summary skill invocation, autoCompactWindow for subagents, TeammateIdle, Ctrl+C at idle prompt). Re-fetched the live v2.1.299 release body after the snapshot (updated_at equals published_at, 2026-10-14T02:49:42Z): after normalising backticks, the 190 bullet entries are identical to the snapshot apart from issue references rendered as 'anthropics/claude-code#99014' and 'anthropics/claude-code#92238' in the API versus '#99014' and '#92238' in the HTML; the release did not change.

Title claims checked. 'Add Idle Compaction Ahead of One-Hour Prompt-Cache Expiry': the entry says a 200K+ token conversation left idle about 54 minutes 'is compacted before its one-hour prompt cache expires', so the note does state compaction happens before the one-hour cache expiry (after about 54 minutes idle, 200K+ tokens). Supported. 'List Several Sandbox Fixes': seven entries in the 2.1.299 notes name the sandbox or sandboxed commands (--plugin-dir write, macOS symlink on denied path, glob re-check after symlink replacement, brace/parenthesis/backslash glob mismatch, /sandbox false success, WSL2 bwrap mkdir, empty .config.json), so 'several' is fair; the awk-guard entry concerns worktree isolation and the article correctly separates it. The article quotes idle compaction as 'Added' in 2.1.299 while the next entry says 'Both need v2.1.290 or later'; the article flags the mismatch without resolving it, which is accurate and appropriately cautious (the notes do not explain whether the floor relates to the feature, its setting, or the env var). The article correctly says the notes list no GitHub release for 2.1.297 and 2.1.298; verified with the API (no tag, no release) and the docs changelog index. Minor wording imprecision: 'The notes list no GitHub release' attributes the absence to the notes, whereas it is the GitHub release list and changelog index that omit them; the substance is accurate and the article makes no claim about their contents. The sandbox fixes are described only in the notes' own words; they are not labelled security fixes by the article, and the article explicitly says no severity, CVE or exploitation information is given. The Context paragraph links the earlier hooks article only to say the notes do not connect the two; confirmed that the linked article exists at /article/2026-10/10-claude-code-21295-adds-onfailure-block-for-hooks-and-21294-and-21296-fix-cases-where-guard-hooks-let-actions-through and it does not discuss sandbox fixes. Date: article states Oct 14, 2026 02:49 UTC, confirmed by API.

Accurate, well-attributed, correctly scoped. Every quoted entry is verbatim in the release snapshot and in the live API body, which did not change; the title, summary and lead are each backed by the cited sources. No defects requiring correction. APPROVE.