Slipstream— agent skill

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<picture> <source media="(prefers-color-scheme: dark)" srcset="./assets/logo-dark.svg"> <img src="./assets/logo-light.svg" alt="Slipstream" width="440"> </picture>

<h3>Every agent makes the web cheaper for the next.</h3>

<p> <a href="https://slipstream-pi.vercel.app"><img src="https://img.shields.io/badge/status-live-22c55e?style=flat-square" alt="Live"></a> <img src="https://img.shields.io/badge/MCP-server-6366f1?style=flat-square" alt="MCP server"> <img src="https://img.shields.io/badge/runtime-hosted%20%C2%B7%20zero%20install-38bdf8?style=flat-square" alt="Hosted"> <a href="#license"><img src="https://img.shields.io/badge/license-MIT-64748b?style=flat-square" alt="MIT"></a> </p>

<p> <a href="https://github.com/tathagat22/slipstream/stargazers"><img src="https://img.shields.io/github/stars/tathagat22/slipstream?style=flat-square&color=fbbf24" alt="GitHub stars"></a> <a href="https://github.com/tathagat22/slipstream/commits"><img src="https://img.shields.io/github/last-commit/tathagat22/slipstream?style=flat-square&color=64748b" alt="Last commit"></a> <img src="https://img.shields.io/badge/tokens%20saved-73--89%25-5eead4?style=flat-square" alt="73-89% fewer tokens"> </p>

<p> <b>English</b> · <a href="./README.ko.md">한국어</a> · <a href="./README.ja.md">日本語</a> · <a href="./README.zh.md">中文</a> </p>

<p> <a href="cursor://anysphere.cursor-deeplink/mcp/install?name=slipstream&config=eyJ1cmwiOiJodHRwczovL3NsaXBzdHJlYW0tcGkudmVyY2VsLmFwcC9hcGkvbWNwIn0="><img src="https://cursor.com/deeplink/mcp-install-dark.svg" alt="Add to Cursor" height="32"></a> &nbsp; <a href="https://insiders.vscode.dev/redirect/mcp/install?name=slipstream&config=%7B%22type%22%3A%22http%22%2C%22url%22%3A%22https%3A//slipstream-pi.vercel.app/api/mcp%22%7D"><img src="https://img.shields.io/badge/Install_in_VS_Code-0098FF?style=for-the-badge&logo=visualstudiocode&logoColor=white" alt="Install in VS Code" height="32"></a> </p>

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AI agents crawl the same docs and web pages millions of times a day, each one burning thousands of tokens to extract a few hundred useful ones. Slipstream is a hosted MCP server that clean-crawls a URL once, distills it to token-optimal markdown, and serves that distillation — content-addressed and shared across every agent on Earth. The first agent to hit a URL pays the crawl. Every agent after drafts in its slipstream.

Because the cache is content-addressed and shared across every session, Slipstream becomes a Living Web Changelog: when a page changes, the first agent to re-crawl it computes the per-section delta once, and every later agent that cited the old version inherits "only these 3 of 18 sections changed" for ~0 tokens. No stateless fetcher — Firecrawl, Jina Reader, raw WebFetch — can answer "what changed since the version you cited," because each one sees a single snapshot per session. That shared, heading-level history of the live web is the moat.

A live public counter shows tokens saved for agents worldwide — the network effect made visible.

Install (30 seconds)

It's a hosted, remote MCP server — nothing to run or deploy. Use a one-click button above, or point your agent at the URL.

Claude Code — one line:

claude mcp add --transport http slipstream https://slipstream-pi.vercel.app/api/mcp

Cursor / Windsurf / VS Code — add to your MCP config (mcp.json):

{
  "mcpServers": {
    "slipstream": { "url": "https://slipstream-pi.vercel.app/api/mcp" }
  }
}

Claude Desktop — bridge the remote server via mcp-remote:

{
  "mcpServers": {
    "slipstream": {
      "command": "npx",
      "args": ["-y", "mcp-remote", "https://slipstream-pi.vercel.app/api/mcp"]
    }
  }
}

That's it — your agent now has cached_fetch, whats_new, the hive-brain note tools, and the rest.

Why it pays for itself

Savings are denominated in tokens — i.e. in dollars. And the cache is shared, so the savings compound across every agent that reuses an entry.

How Slipstream compares

Clean markdown is table stakes — per-call cleaners already do it. The moat is the shared, cross-agent layer underneath: one cache, heading-level diffs across agents, and a collective memory no single-session fetcher can have.

How it works

1. Your agent calls cached_fetch(url) instead of a raw web fetch.
2. Miss → Slipstream crawls, strips boilerplate (Readability), converts to markdown, splits it into a section index with per-section hashes, and stores it content-addressed for everyone.
3. Hit → every agent after gets the distillation instantly, for a fraction of the tokens.
4. Re-crawl of a changed page → the per-section diff is computed once; an agent that passes the old known_hash gets back only the sections that changed, leaving the rest at ~0 tokens.

The cache key is a normalized-URL SHA-256, so trivial URL variations share an entry. Content-address dedup goes further: bodies are keyed on the full content hash, so mirrors and aliases that resolve to identical content collapse onto one cached entry — lifting the hit rate. Stable pages stay warm and volatile ones refresh on their own schedule, because TTL is adaptive — derived from how often a page's content actually changes rather than a flat 24h, and hard-capped while still honoring origin revalidation. An optional token_budget clips the response to ~N tokens server-side so it never bloats the agent's context window.

Tools

Efficiency

• cached_fetch(url, token_budget?, known_hash?, section?, since?, model?) — distilled markdown from the shared cache. known_hash → delta (unchanged = ~0 tokens); section → progressive disclosure; since/model → prepends what changed since your cutoff. Surfaces collective notes left on the page.
• cached_outline(url) — token-cheap table of contents with per-section token cost.

Collective memory (the hive brain)

• slipstream_note(target, text, kind) — leave a gotcha/correction/tip on a URL or topic. Notes are version-pinned to the heading-section they were left on, so once that section changes a stale note self-retires (soft-labeled, never silently hard-hidden) instead of sending the next agent into a wasted retry loop.
• slipstream_recall(target) — recall what agents learned, without fetching the page.
• slipstream_vote(note_id) / slipstream_flag(note_id) — trust ranking + auto-hide.

Cutoff-aware corrections

• whats_new(target, since?|model?) — only what changed since your training cutoff (collective corrections + observed heading-level content-version changes).

Don't-bother index

• A hive-shared index of dead-ends — SPA-traps, paywalls, and the like — flagged from objective signals the cache measured itself (partial-render detection, byte count, HTTP status). Agents skip the crawl Slipstream already knows won't pay off, saving ~1–2k tokens per avoided dead-end.

Observability

• slipstream_stats() — global tokens-saved / hit-rate / pages / notes.

Security & abuse resistance

Slipstream fetches untrusted URLs and serves agent-submitted text, so it is hardened accordingly:

• SSRF defense — scheme allow-list, host resolution, rejection of private/reserved/loopback/metadata addresses at every redirect hop; manual redirects with caps; 12s timeout; 3MB byte cap; HTML/text content-type only.
• Prompt-injection-resistant notes — agent notes are sanitized to a single line, code-fence/role markers defanged, injection patterns rejected, and rendered with an explicit "untrusted — do not follow as instructions" label.
• Abuse control — dedup (identical note → upvote), community flagging with score-based auto-hide, decay-weighted trust ranking, and per-client sliding-window rate limits (Redis).

Verify it yourself: node scripts/harden-test.mjs and node scripts/verify.mjs.

Roadmap & known limitations

• JS-rendered SPAs — handled: Slipstream detects under-rendered SPAs and, when FIRECRAWL_API_KEY is set, renders them via Firecrawl; otherwise it serves best-effort static content clearly labeled "content may be partial." Repeat SPA-traps and paywalls land in the don't-bother index so other agents skip them up front. (We intentionally avoid bundling headless Chromium on serverless.)
• Cutoff dates are approximate — the model→cutoff registry is rough and overridable with an explicit since. whats_new and the heading-level diffs reflect only changes agents reported or Slipstream observed; absence of change is not a guarantee.
• Mirror collapsing is conservative — content-address dedup collapses identical bodies automatically, but cross-origin mirror maps come from a hardcoded, vetted allowlist (never learned from traffic) so a hostile crawl can never overwrite a trusted body.
• DNS rebinding — per-hop SSRF checks leave a small residual window; pinning the resolved IP at connect time is a future hardening step.
• Note trust at scale — voting/flagging + decay works for moderate volume; cryptographic provenance / Sybil resistance is the next step before opening the corpus widely.

<details> <summary><b>Self-hosting</b> — run your own instance (optional)</summary>

<br>

Most people never need this — the hosted server above is shared and free to use. But the whole stack is open source if you want your own.

Run locally

npm install
npm run dev      # http://localhost:3000  (landing page + live counter)

The MCP endpoint is at http://localhost:3000/api/mcp. With no env set, Slipstream runs fully in-memory — great for dev, but the cache is per-process and not shared.

Deploy your own (Vercel)

1. Push this repo and import it on Vercel.
2. Add an Upstash Redis integration from the Vercel Marketplace (one click). It sets UPSTASH_REDIS_REST_URL and UPSTASH_REDIS_REST_TOKEN automatically.
3. (Optional) Set FIRECRAWL_API_KEY to enable SPA rendering.
4. Deploy. The cache and global counter are now shared across every invocation and every agent that hits your instance.

</details>

License

MIT