Week 36 · August 31 – September 4, 2026 changedwhats-new/2026-w36
Nearest release: v2.1.272, published an hour before upstream edited the page. Shown because the two are within 24 hours of each other. Nothing here says the release caused the edit.
Upstream edited this page at 15 Sep 2026 00:38 UTC, give or take a minute or two: the time comes from Anthropic’s own sitemap rather than from a commit. This site recorded the change at 20 Oct 2026 18:37 UTC.
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33> Switch to Claude Fable 5.1, let computer use run in the background on Desktop, and watch Claude's edits in a live /diff panel.
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5<div className="digest-meta">
6 <span>Releases <a href="/docs/en/changelog#2-1-251">v2.1.251 → v2.1.261</a></span>
7 <span>4 features · August 31 – September 4</span>
8</div>
5Releases [v2.1.251 → v2.1.261](/docs/en/changelog#2-1-251)
64 features · August 31 – September 4
97
10<div className="digest-feature">
11 <div className="digest-feature-header">
12 <span className="digest-feature-title">Claude Fable 5.1</span>
13 <span className="digest-feature-pill">new model</span>
14 </div>
8Claude Fable 5.1
9new model
1510
16 <p className="digest-feature-lede">Claude Fable 5.1 is available in Claude Code with a 1M-token context window, and the <code>fable</code> alias now selects it. In Claude apps gateway sessions, <code>fable</code> still selects Fable 5. If your gateway serves Fable 5.1, run <code>/model claude-fable-5-1</code>. Requires v2.1.257 or later.</p>
11Claude Fable 5.1 is available in Claude Code with a 1M-token context window, and the `fable` alias now selects it. In Claude apps gateway sessions, `fable` still selects Fable 5. If your gateway serves Fable 5.1, run `/model claude-fable-5-1`. Requires v2.1.257 or later.
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18 <p className="digest-feature-try">Switch the current session to Fable 5.1 and save it as your default:</p>
13Switch the current session to Fable 5.1 and save it as your default:
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20 ```text Claude Code theme={null}
21 > /model fable
22 ```
15```text Claude Code theme={null}
16> /model fable
17```
2318
24 <p className="digest-feature-try">On the Anthropic API, the picker lists Fable only once the server reports it available for your organization, but typing <code>/model fable</code> checks with the server directly.</p>
19On the Anthropic API, the picker lists Fable only once the server reports it available for your organization, but typing `/model fable` checks with the server directly.
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26 <a className="digest-feature-link" href="/docs/en/model-config#work-with-fable">Work with Fable</a>
27</div>
21[Work with Fable](/docs/en/model-config#work-with-fable)
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29<div className="digest-feature">
30 <div className="digest-feature-header">
31 <span className="digest-feature-title">Computer use runs in the background on Desktop</span>
32 <span className="digest-feature-pill">Desktop</span>
33 </div>
23Computer use runs in the background on Desktop
24Desktop
3425
35 <p className="digest-feature-lede">On macOS, computer use in the Claude Code Desktop app now works in the background: Claude sees and acts in the apps you've approved while you keep working. Background computer use is in beta on Pro and Max plans.</p>
26On macOS, computer use in the Claude Code Desktop app now works in the background: Claude sees and acts in the apps you've approved while you keep working. Background computer use is in beta on Pro and Max plans.
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37 <Frame>
38 <img className="w-full" src="https://mintcdn.com/claude-code/f9HTZGyMtxIFOUgt/images/whats-new/background-computer-use.jpg?fit=max&auto=format&n=f9HTZGyMtxIFOUgt&q=85&s=a599a6c6fa544cb8d1b426b93706caf4" alt="A Claude Code Desktop session where Claude asks to use Xcode, with a Computer use permission card that reads Let Claude see and act in the apps you approve, in the background or with full control of your screen, next to an Enable button" width="1440" height="810" data-path="images/whats-new/background-computer-use.jpg" />
39 </Frame>
28
4029
41 <a className="digest-feature-link" href="/docs/en/desktop#let-claude-use-your-computer">Let Claude use your computer</a>
42</div>
30[Let Claude use your computer](/docs/en/desktop#let-claude-use-your-computer)
4331
44<div className="digest-feature">
45 <div className="digest-feature-header">
46 <span className="digest-feature-title">Live diff panel in fullscreen rendering</span>
47 <span className="digest-feature-pill">v2.1.260</span>
48 </div>
32Live diff panel in fullscreen rendering
33v2.1.260
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50 <p className="digest-feature-lede">In fullscreen rendering, <code>/diff</code> now opens a panel beside the conversation instead of a viewer you have to close. The panel lists the changed files with their added and removed line counts and refreshes each time Claude edits a file or runs a shell command. Select lines in the panel with the mouse to attach them to your next prompt.</p>
35In fullscreen rendering, `/diff` now opens a panel beside the conversation instead of a viewer you have to close. The panel lists the changed files with their added and removed line counts and refreshes each time Claude edits a file or runs a shell command. Select lines in the panel with the mouse to attach them to your next prompt.
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52 <Frame>
53 <video autoPlay muted loop playsInline className="w-full" src="https://mintcdn.com/claude-code/f9HTZGyMtxIFOUgt/images/whats-new/diff-panel.mp4?fit=max&auto=format&n=f9HTZGyMtxIFOUgt&q=85&s=9d7553c19e7f227891cd95f1f59d796d" data-path="images/whats-new/diff-panel.mp4" />
54 </Frame>
37<video autoPlay muted loop playsInline src="https://mintcdn.com/claude-code/f9HTZGyMtxIFOUgt/images/whats-new/diff-panel.mp4?fit=max&auto=format&n=f9HTZGyMtxIFOUgt&q=85&s=9d7553c19e7f227891cd95f1f59d796d" />
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56 <p className="digest-feature-try">With fullscreen rendering on, inside a git repository, and in a terminal at least 110 columns wide, toggle the panel:</p>
39With fullscreen rendering on, inside a git repository, and in a terminal at least 110 columns wide, toggle the panel:
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58 ```text Claude Code theme={null}
59 > /diff
60 ```
41```text Claude Code theme={null}
42> /diff
43```
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62 <p className="digest-feature-try">Run <code>/diff</code> again or click the <code>✕</code> in its header to close it.</p>
45Run `/diff` again or click the `✕` in its header to close it.
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64 <a className="digest-feature-link" href="/docs/en/interactive-mode#diff-panel">Diff panel</a>
65</div>
47[Diff panel](/docs/en/interactive-mode#diff-panel)
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67<div className="digest-feature">
68 <div className="digest-feature-header">
69 <span className="digest-feature-title">Find unused skills with /skill-doctor</span>
70 <span className="digest-feature-pill">CLI</span>
71 </div>
49Find unused skills with /skill-doctor
50CLI
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73 <p className="digest-feature-lede"><code>/skill-doctor</code> shows what each of your skills costs in context and how often it gets used, so you can decide which ones to turn off. Every skill in the <a href="/docs/en/skills#skill-descriptions-are-cut-short">skill listing</a> adds to your context on every turn, whether or not Claude ever uses it. Requires v2.1.252 or later and isn't available in sessions that skip <a href="/docs/en/env-vars#features-that-need-feature-flag-fetching">feature-flag fetching</a>.</p>
52`/skill-doctor` shows what each of your skills costs in context and how often it gets used, so you can decide which ones to turn off. Every skill in the [skill listing](/docs/en/skills#skill-descriptions-are-cut-short) adds to your context on every turn, whether or not Claude ever uses it. Requires v2.1.252 or later and isn't available in sessions that skip [feature-flag fetching](/docs/en/env-vars#features-that-need-feature-flag-fetching).
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75 <p className="digest-feature-try">Run it in an interactive session to open the report in the <code>/plugin</code> manager's <strong>Stats</strong> tab:</p>
54Run it in an interactive session to open the report in the `/plugin` manager's **Stats** tab:
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77 ```text Claude Code theme={null}
78 > /skill-doctor
79 ```
56```text Claude Code theme={null}
57> /skill-doctor
58```
8059
81 <p className="digest-feature-try">In non-interactive mode with <code>-p</code>, Claude Code prints the report as text instead.</p>
60In non-interactive mode with `-p`, Claude Code prints the report as text instead.
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83 <a className="digest-feature-link" href="/docs/en/skills#find-unused-skills">Find unused skills</a>
84</div>
62[Find unused skills](/docs/en/skills#find-unused-skills)
8563
86<div className="digest-wins">
87 <p className="digest-wins-title">Other wins</p>
64Other wins
8865
89 <div className="digest-wins-grid">
90 <div>A <a href="/docs/en/hooks#premodelswitch"><code>PreModelSwitch</code></a> hook can block a model switch you request, and a <a href="/docs/en/hooks#postmodelswitch"><code>PostModelSwitch</code></a> hook can add context for Claude after the session's model changes</div>
91 <div><a href="/docs/en/costs#prompt-cache-statistics"><code>/cost</code></a> adds a <code>Prompt cache (main)</code> line: the share of input tokens served from cache, the cache misses, whether the cache is warm, and a likely cause for the last miss when Claude Code can name one. Status line scripts get a matching <code>prompt\_cache</code> object</div>
92 <div>Organizations can list HTTP and SSE MCP servers under the <a href="/docs/en/managed-mcp#provide-servers-through-managed-settings"><code>managedMcpServers</code></a> managed setting to give them to every user, in addition to the servers that users add on their own</div>
93 <div><code>/effort</code> and the <code>/model</code> picker now <a href="/docs/en/model-config#adjust-effort-level">save a separate effort level for each model</a>; press <code>s</code> instead of <code>Enter</code> to apply a level to the current session only</div>
94 <div>By default, the auto mode classifier <a href="/docs/en/permission-modes#what-the-classifier-blocks-by-default">now also blocks</a> actions such as requesting credentials from the cloud instance-metadata endpoint or connecting to sibling containers that Claude didn't start</div>
95 <div>In auto mode, Claude Code asks you before Claude <a href="/docs/en/permission-modes#first-read-outside-the-working-directories">first reads a file outside your working directories</a>, with an option to block such reads from then on</div>
96 <div>Raise <a href="/docs/en/settings-reference#bashoutputmaxchars"><code>bashOutputMaxChars</code></a> and <a href="/docs/en/settings-reference#taskoutputmaxchars"><code>taskOutputMaxChars</code></a>, up to 128,000 characters, so Claude receives more of the output from a successful command or background task inline</div>
97 <div>The prompt's <a href="/docs/en/interactive-mode#make-ctrl-w-delete-back-to-whitespace">word-editing shortcuts follow readline</a> for everyone, and the <code>keybindingFlavor</code> setting no longer has any effect. <code>Ctrl+W</code> deletes back to the previous whitespace, and <code>Alt+B</code>, <code>Alt+F</code>, and <code>Alt+D</code> treat punctuation such as <code>/</code> and <code>.</code> as word breaks</div>
98 <div>If you set <code>defaultMode</code> to <code>"bypassPermissions"</code> in a project's <code>.claude/settings.json</code> or <code>.claude/settings.local.json</code>, it <a href="/docs/en/permission-modes#which-mode-a-session-starts-in">no longer takes effect</a> and the session starts in Manual mode; set <code>"bypassPermissions"</code> in user or managed settings instead, or pass `--permission-mode`</div>
99 <div>Seat-based Enterprise plans now <a href="/docs/en/model-config#default-model-setting">default to Opus 5</a></div>
100 <div>In the VS Code extension, click the model name at the bottom of the prompt box to <a href="/docs/en/vs-code#use-the-prompt-box">open the model picker</a></div>
101 <div>In the VS Code extension, select <strong>Output styles</strong> in the command menu's Customize section to <a href="/docs/en/vs-code#use-the-prompt-box">pick an output style</a>, including your custom ones</div>
102 </div>
103</div>
66A [`PreModelSwitch`](/docs/en/hooks#premodelswitch) hook can block a model switch you request, and a [`PostModelSwitch`](/docs/en/hooks#postmodelswitch) hook can add context for Claude after the session's model changes[`/cost`](/docs/en/costs#prompt-cache-statistics) adds a `Prompt cache (main)` line: the share of input tokens served from cache, the cache misses, whether the cache is warm, and a likely cause for the last miss when Claude Code can name one. Status line scripts get a matching `prompt_cache` objectOrganizations can list HTTP and SSE MCP servers under the [`managedMcpServers`](/docs/en/managed-mcp#provide-servers-through-managed-settings) managed setting to give them to every user, in addition to the servers that users add on their own`/effort` and the `/model` picker now [save a separate effort level for each model](/docs/en/model-config#adjust-effort-level); press `s` instead of `Enter` to apply a level to the current session onlyBy default, the auto mode classifier [now also blocks](/docs/en/permission-modes#what-the-classifier-blocks-by-default) actions such as requesting credentials from the cloud instance-metadata endpoint or connecting to sibling containers that Claude didn't startIn auto mode, Claude Code asks you before Claude [first reads a file outside your working directories](/docs/en/permission-modes#first-read-outside-the-working-directories), with an option to block such reads from then onRaise [`bashOutputMaxChars`](/docs/en/settings-reference#bashoutputmaxchars) and [`taskOutputMaxChars`](/docs/en/settings-reference#taskoutputmaxchars), up to 128,000 characters, so Claude receives more of the output from a successful command or background task inlineThe prompt's [word-editing shortcuts follow readline](/docs/en/interactive-mode#make-ctrl-w-delete-back-to-whitespace) for everyone, and the `keybindingFlavor` setting no longer has any effect. `Ctrl+W` deletes back to the previous whitespace, and `Alt+B`, `Alt+F`, and `Alt+D` treat punctuation such as `/` and `.` as word breaksIf you set `defaultMode` to `"bypassPermissions"` in a project's `.claude/settings.json` or `.claude/settings.local.json`, it [no longer takes effect](/docs/en/permission-modes#which-mode-a-session-starts-in) and the session starts in Manual mode; set `"bypassPermissions"` in user or managed settings instead, or pass `--permission-mode`Seat-based Enterprise plans now [default to Opus 5](/docs/en/model-config#default-model-setting)In the VS Code extension, click the model name at the bottom of the prompt box to [open the model picker](/docs/en/vs-code#use-the-prompt-box)In the VS Code extension, select **Output styles** in the command menu's Customize section to [pick an output style](/docs/en/vs-code#use-the-prompt-box), including your custom ones
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10568[Full changelog for v2.1.251–v2.1.261 →](/docs/en/changelog#2-1-251)
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