SourceCapsule

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Save X/Twitter threads & Articles as clean Markdown for LLMs — plus a one-file offline HTML archive.

One click on a post, thread, or Article produces an agent-ready folder: a clean .llm.md you can paste straight into Claude or ChatGPT, the real image files it references, and a self-contained .html that opens fully offline with media and quoted posts inlined. No screenshots, no copy-paste mangling, no dead links when the thread disappears.

Why this instead of copy-paste or screenshots?

• LLMs read text, not pixels. You get Markdown in reading order with author, timestamps, and the source URL — plus real image files an agent can actually look at.
• Threads resist copying. X virtualizes long threads and lazy-loads media; SourceCapsule scrolls, captures, and reports honestly what it got (and what it could not get).
• It archives, not just extracts. The same click yields a self-contained offline HTML file with images, inline video, and quoted posts embedded — still readable in ten years.

Install (30 seconds)

1. Install Tampermonkey or Violentmonkey.
2. Install SourceCapsule from Greasy Fork (auto-updates), or open sourcecapsule.user.js and click Install.
3. Open any post, thread, or Article on x.com and click Create AI link.

The source file is also the shipped artifact: plain JavaScript, no production build step.

What is new in v1.5

• Reply archive (experimental). Capture the replies to a post — full text, author, timestamp, parent id, and media links — as threaded Markdown plus a full-text CSV. See Reply archive below.
• A shorter menu. The post drop-down had grown to ten items, which buried the common actions; it is now six. Nothing lost capability: Save locally + create AI link was two actions that are both still listed separately, and Download ZIP (HTML + Markdown) is the non-Chromium fallback that Save to library already falls back to on its own.
• One image is one media link. X serves the same image with and without a file extension before the query string, so an image seen by two capture layers used to be recorded twice. When two URLs name the same asset, the full-size rendition wins.

What is new in v1.4.1

• Complete media in AI-readable links. Choosing Create AI readable link now packages the same captured images and video poster stills as a local save plus share. Sharing no longer depends on running a local save first. The existing 25 MB hosted-share cap still applies.

What is new in v1.4

• Strict export mode (on by default). After every recovery layer runs, SourceCapsule walks the finished model and blocks the download if the reader would see a dead-end: a quoted post with no canonical permalink, a quoted post whose content couldn't be captured, an image that never inlined, or a video with neither bytes nor a poster. The block modal lists exactly what is broken, offers a Copy diagnostic bundle button (self-contained JSON with URL, verdict, counts, and a media-stripped model skeleton), and requires Ship it anyway or Cancel export to proceed. Toggle it from the userscript-manager menu or the extension popup.
• Three-layer quote-source recovery. The exporter now catches a quoted tweet's canonical permalink even when X's DOM drops the anchor: (a) parent→quoted ref triples harvested passively from the GraphQL responses X's own web app already downloaded, (b) syndication pool matching for the leftovers, (c) per-thread-post syndication that reuses the fetched quoted_tweet payload to patch source URLs and rebuild the card in one round-trip.
• Author-profile link fallback. In the rare case where every recovery layer misses, a quoted card links to the author's X profile instead of showing "Source URL unavailable" — never a dead-end for the reader.
• Thread-menu escape hatch. Every focused-post button now exposes Save full thread in its drop-down, regardless of auto-detection. Choosing it forces a full-column scroll so late-loading same-author replies are always captured — the "I know it's a thread, why does it say Save post" scenario is fixable in one click.
• Share Worker previews. Shared capsules now emit Content-Length on GET and HEAD, so Slack, Discord, and Twitter link previews render the shared images and pages correctly.
• First-try recovery hardening. Quote-only GraphQL responses are retained, quote cards that never mounted are rebuilt from the parent payload, Article images survive virtualization, DOM-only polls/card previews survive authoritative quote upgrades, and ambiguous video URLs are never attached to a post by guesswork. Media downloads are signature-checked so an HTTP error page cannot masquerade as a captured image.
• Clearer controls and packaging. The redesigned MV3 popup explains page readiness and folder-vs-ZIP delivery, with accessible switches, keyboard navigation, dark mode, and reduced-motion support. One-off HTML + Markdown downloads now arrive together in one ZIP.

The product remains local-first. Nothing is uploaded until you click Create AI link (the default button action, which publishes at the 7-day default expiry) or choose the combined save-and-share flow, which asks for the expiry first — and the reply archive never uploads at all. When a save and a share are combined, the local copy is completed first, so an upload failure cannot take it away. Shared capsules exclude raw video, are capped at 25 MB, and retain source links when media cannot be included.

Use it

On the X timeline, a status page, or an Article:

• Click Create AI link — the default action on every button. On a focused post that is a thread, one click produces one link covering the whole thread, not a link per post. It uploads immediately with the 7-day default expiry.
• If a timeline card says Open post first, open the post and save from the status/Article page; the feed preview does not contain enough content for a complete archive.
• Click ... beside it for:
  • Create AI link (full thread) — on a focused post page
  • Save full thread — on a focused post page
  • Save to library
  • Save with note and tags
  • Copy clean Markdown
  • Capture replies (experimental) — on a focused post page
  • Download reply archive — on a focused post page

The first library save asks you to choose a root folder. Desktop Chromium writes folders directly. Browsers without the File System Access API receive a zip with the same structure.

<library root>/
  _sourcecapsule-index.md
  2026-07-02/
    <handle>-<status-id>/
      <handle>-<status-id>.html
      <handle>-<status-id>.llm.md
      AI_LINK.txt              # only after an AI readable link is created
      media/
      README.txt

Thread capture is deliberately honest: it includes same-author posts visible during a progressive scroll, marks post boundaries, and records best-effort completeness in the manifest. X can virtualize or withhold posts, so this is not yet a guarantee of every reply in very long threads.

Reply archive (experimental)

Everything above archives a post and its thread. This archives the replies to a post — what people said back — as threaded Markdown plus a full-text CSV.

On an opened post, click ... then:

1. Capture replies (experimental) — one click walks all three of X's reply surfaces (Latest, Top, Relevant) and merges them. Expect a few minutes on a large conversation; progress is reported per surface. Leave the tab in front.
2. Download reply archive — writes sourcecapsule-replies-<id>.md and .csv.

Replies accumulate across runs and never shrink. A populated field is never overwritten by an empty one and the longer text always wins, so a truncated preview cannot clobber full long-form text, and a reply that disappears from a later surface keeps what was already captured. Storage is IndexedDB; if a write fails, it says so rather than losing the run silently.

Reply media is recorded as links only — downloading media for thousands of replies is out of scope. Images, video, and posters are listed as URLs you can follow.

How complete is it?

Every archive reports what it captured, lists any reply id it knows about but could not fetch, and refuses to treat X's public reply counter as a denominator. Measured across three real conversations:

Replies on X (counter)	Archived with content	Known but uncaptured
764	636	0
670	537	0
32	36	0

In every case the archive captured 100% of the replies X actually delivered to the browser. The shortfall against the counter in the first two is replies X never served at all — deleted, blocked, restricted, or simply never returned by any surface — which are undetectable by construction. The third row exceeds its counter because X's number appears to count direct replies only, while the archive also captures nested replies-to-replies.

Coverage is best effort and the receipt in every export says so. Deleted, private, and never-delivered replies remain unknowable.

AI readable links

The userscript ships pointing at the hosted share service (https://sourcecapsule-share.wolfgang-aura.workers.dev): a Cloudflare Worker + R2 backend with per-IP rate limiting on link creation, a 25 MB package cap, and 1/7/30-day expiry with daily cleanup. To try it:

1. Open a post on x.com.
2. Click Create AI link. It publishes at the 7-day default expiry; to pick 1 or 30 days, use Save with note / tags and share from the receipt instead.
3. The resulting URL is copied to your clipboard.
4. Paste the URL into a new tab. Add .md to the capsule URL for the clean Markdown endpoint.

When the link expires, the archived copy is deleted but the link does not go blank: it serves a short notice page pointing back to the original post on X, so whoever you sent it to can still find the source. The .md endpoint serves the same notice as Markdown. That pointer holds only the post's public permalink, title, and author handle — nothing about who made the link — and is removed 180 days after expiry, or immediately if you delete the link.

Successful links are remembered in this browser under SourceCapsule: Recent AI readable links. Expired links remain visible but greyed out. When a link is created from a local-save receipt or the combined save-and-link flow, SourceCapsule also writes AI_LINK.txt beside the saved Markdown so the same link can be recovered from the library folder.

Develop against a local share service

cd SourceCapsule
npm.cmd install
npm.cmd run dev:share

Leave that PowerShell window open, then open Tampermonkey while on x.com and set SourceCapsule: Share service URL to http://127.0.0.1:8787. Other hosts also need an @connect grant in the userscript header (and a host_permissions entry in the extension manifest).

Self-host the share service

The backend is a small Cloudflare Worker with an R2 bucket. Deployment details are in share-worker/README.md. Accounts, billing, and permanent-link quotas are intentionally not part of this first share release.

Test the Chrome extension (unpacked beta)

cd SourceCapsule
npm.cmd run build:extension

Then in Chrome:

1. Open chrome://extensions.
2. Turn on Developer mode in the top-right.
3. Click Load unpacked.
4. Choose dist\sourcecapsule-extension.
5. Disable the SourceCapsule userscript in Tampermonkey for x.com to avoid duplicate buttons.
6. Refresh a status page and test quick save, this-post-only, copy Markdown, and AI readable links.

This package reuses the tested userscript engine through a thin compatibility layer and has passed the automated package suite plus live-X validation. It remains an unpacked beta until a separate Chrome Web Store publication is prepared.

Unattended capture from the command line (experimental)

One command captures a post and returns a ready AI readable link, with no clicks, no prompts, and no clipboard use:

node scripts\sourcecapsule-capture.mjs --url "https://x.com/handle/status/123" --json

{
  "ok": true,
  "sourceUrl": "https://x.com/handle/status/123",
  "viewUrl": "https://sourcecapsule-share.wolfgang-aura.workers.dev/c/...",
  "markdownUrl": "https://sourcecapsule-share.wolfgang-aura.workers.dev/c/....md",
  "expiresAt": "2026-09-06T12:51:33.824Z",
  "complete": true,
  "warnings": []
}

Only that JSON goes to stdout. Progress and diagnostics go to stderr, and a failure exits nonzero.

It reuses the normal capture path. The extension opens the post in a background window, waits for the passive GraphQL recovery layer, runs the same share export a menu click would run, and keeps strict completeness validation on. If strict mode still finds missing evidence after every recovery layer and retry, the command fails with needs_owner and lists what is missing, rather than publishing a capsule with dead ends in it:

{
  "ok": false,
  "error": "needs_owner",
  "message": "Strict capture could not recover missing evidence.",
  "counts": { "imageFetchFailed": 2 }
}

Setup

npm.cmd run build:extension
npm.cmd run install:native-host

The installer needs no administrator rights. It writes everything under HKCU and installs the host into %LOCALAPPDATA%\SourceCapsule\native-host, registering it for Chrome, Edge, and Brave. The registered host is a two-line .cmd that runs your signed node.exe, so Windows Smart App Control allows it.

Run the installer from an ordinary PowerShell window. A shell opened inside a packaged app, such as the Claude desktop app, redirects the files and registry keys into that app's private copy, where a normally started browser cannot see them. The installer detects this and exits with an error instead of reporting success.

Then load dist\sourcecapsule-extension as an unpacked extension and confirm its ID reads gaclgcfljpjojddiikddejenlnjaggie. The ID is pinned by a key in the manifest, because the native messaging host has to name a fixed extension origin.

Verify the bridge with:

node scripts\sourcecapsule-capture.mjs --ping

Keeping the extension loaded across restarts

--load-extension installs at Chromium's COMMAND_LINE location. The browser records it in the profile but does not load it again on a start that lacks the flag, so an ordinary restart has no SourceCapsule extension at all: no service worker, no native port, and a CLI that cannot reach the host. The worker is not asleep; it does not exist.

Install a launcher that always passes the flag:

powershell -ExecutionPolicy Bypass -File scripts\start-sourcecapsule-browser.ps1 -InstallShortcut -InstallStartup

That puts Brave with SourceCapsule on the Desktop, in the Start Menu, and in Startup. Start the browser from it and the bridge is always there. Starting it any other way silently drops the extension.

The launcher also passes --disable-features=CalculateNativeWinOcclusion, and the capture needs it. The capture window is deliberately unfocused, Windows occlusion tracking treats a fully covered window like a hidden tab, and a browser without the flag fetches a thread's conversation and never renders it: the capsule comes back holding the root post alone. If you installed the shortcut before this flag existed, run -InstallShortcut -InstallStartup again.

To check or repair the current state:

powershell -ExecutionPolicy Bypass -File scripts\start-sourcecapsule-browser.ps1 -Status
powershell -ExecutionPolicy Bypass -File scripts\start-sourcecapsule-browser.ps1 -Restart -Verify

-Status reports whether the running browser has the flag and exits nonzero when it does not. -Restart closes it and starts it correctly; a browser that is already running without the flag cannot be fixed by launching it again, because the second launch just hands its arguments to the existing process. -Verify then polls --ping until the bridge answers, so the launcher cannot report success while the bridge is still down.

The alternative is a one-time Load unpacked of dist\sourcecapsule-extension from brave://extensions, which records the extension at the UNPACKED location and survives restarts without any launcher. It is a manual UI step, and it cannot coexist with the command-line copy: same key, same extension ID.

Google Chrome needs Load unpacked. Since Chrome 137, branded Google Chrome ignores --load-extension. The launcher picks Brave, then Edge, then Chrome. When it ends up on Chrome, it leaves out --load-extension, says so, and still passes the occlusion flag. Load the extension once from chrome://extensions (Developer mode, Load unpacked, select dist\sourcecapsule-extension). Then start Chrome from the shortcut. -Status cannot see an unpacked extension on a command line, so on Chrome confirm with --ping. Chromium and Chrome for Testing still honor the flag.

How it fits together

The browser spawns native messaging hosts; nothing outside can dial into the browser. So the service worker holds a long-lived port to the host, the host owns a Windows named pipe, and the CLI connects to that pipe. One host owns the pipe at a time, which is also what enforces one capture at a time. Timeouts are bounded at every hop and the URL is validated against a canonical x.com/<handle>/status/<id> pattern in both the CLI and the extension.

Known limits

• Windows only. The pipe and the installer are Windows-specific.
• The browser must be running with the extension loaded and signed into X, which in practice means starting it from the launcher above.
• If the extension is not actually running, the bridge reports Specified native messaging host not found. That is almost always a start without --load-extension (or, on Google Chrome, a missing Load unpacked), not a bad registration.
• The capture window is visible but never focused. A hidden tab has requestAnimationFrame paused and timers throttled, which starves the media force-load pass and manufactures strict-mode blockers.

What is captured

Content	Result
Text, headings, lists, links	Preserved in reading order
Same-author thread continuations	Captured best-effort, with explicit post boundaries
Images	Inlined at the highest accessible resolution
Quoted posts	Rebuilt as selectable cards using X syndication data
Downloadable MP4	Embedded in a full offline HTML archive
HLS-only or blocked video	Poster and source link; clearly marked incomplete
Agent bundle	Markdown plus real image/poster files; raw video excluded
Replies to a post	Threaded Markdown + CSV with full text; media as links only (experimental)
Provenance	Source URL, author, timestamp, warnings, and capture manifest

An archive never claims more than it actually preserved. Missing media, preview-only long-form quotes, and incomplete video are visible in both the rendered output and manifest. For long-form (note) posts, SourceCapsule recovers the full text when X has already delivered it to your browser while the page was open (no extra requests); otherwise the preview is clearly flagged as truncated.

Settings

Open the userscript-manager menu while on x.com:

• Layout: folders by date (default) or flat.
• Contents: full archive (default) or lean Markdown + media.
• Strict Export: on by default; blocks silent incomplete downloads after recovery retries.
• Reply Context: on by default; prepends the parent post when exporting a reply.
• Share service URL: localhost for development, your Worker domain for production.
• Change export folder: select another library root.
• Floating button: optional; off by default.

Development

Requirements: Node.js 18+.

cd SourceCapsule
npm.cmd install
npm.cmd test
npm.cmd run lint
npm.cmd run format:check
npm.cmd run build:extension

The automated suite covers the DOM-free renderer, jsdom extraction/thread behavior, share Worker, and extension packaging. It does not replace manual testing against X's live DOM.

Privacy and security

• Normal saves stay on your machine.
• Sharing requires an explicit confirmation and an expiry.
• Share IDs are high-entropy and unguessable, but anyone holding a link can read it.
• Shared pages send noindex and restrictive security headers.
• The service rejects unsupported file paths and caps each capsule at 25 MB.
• A deletion token is created client-side and is not exposed in the public URL.
• After expiry only a back-link to the original public post survives; deleting a link removes that too.

Do not share sensitive posts through a public deployment until authentication and abuse controls exist. “Unguessable” is useful access control for v1 testing, not a replacement for user accounts.

Deliberately out of scope for v1.5

• AI summaries, chat, OCR, transcripts, or media descriptions
• Bookmark scraping and bulk export
• Permanent-link allowances, user accounts, billing, or subscriptions
• A hosted dashboard or full-text search
• HLS video reassembly
• Guaranteed capture of every post in arbitrarily long threads
• Downloading reply media (the reply archive records links only)
• Chrome Web Store publication

License

MIT. See LICENSE.