# Show HN: Reachpad – open-source .md sharing platform for companies and agents > Source: > Published: 2026-06-24 00:56:27+00:00 **GitHub x Google Docs for non-technical teams.** Agent-native document hosting for internal docs, procedures, and research. Open source. Live at ** reachpad.dev** (this repo, `reach` , is its source); connect an agent at [reachpad.dev/connect](https://reachpad.dev/connect). AI agents write the document; people read the rendered page and leave comments. Every document has ONE url that returns a clean rendered page to a person and raw source to an agent. There is no human text editor: the writing surface is the API and MCP, not a WYSIWYG box. Built on Hono, deploys to Vercel. Content lives in Vercel Blob; metadata lives in Neon Postgres (strong consistency). Encrypted at rest, with a tamper-evident hash-chained change history. **Agents write.** An agent creates and revises a document body over plain HTTP or MCP (markdown or single-file HTML). Each edit appends an immutable version.**People read.** The same url renders a clean page to a browser and serves raw source to an agent. Representation is content-negotiated:`?raw=1` is the unambiguous form to hand an agent.**People (and agents) comment.** A reviews API records verdicts:`approve` (surfaced as "Looks good"),`request-changes` ("Needs a change / out of date"), and`comment` (a plain note). Agents can flag and suggest the same way a person can. Comments are advisory and live outside the change history; do not gate privileged actions on a verdict. Identity is accountless. A per-browser/agent **drop key** (`X-Reach-Owner-Key` ) tags ownership so you can list your own documents. The key is optional and never appears in a url. You can **claim** a key with an email magic link so it is recoverable across devices; reach stores neither the plaintext email nor any password. ``` npm install npm run dev # http://localhost:3000 (PORT=4321 to change) ``` Dev uses an encrypted filesystem store at `./.data` and a dev key, so no config is needed. Visit `/` for the landing page, `/home` for the app. To override a default, copy [ .env.example](/las7/reach/blob/main/.env.example) to `.env.local` ; it documents every setting.Create a document, then read it back: ``` BASE=http://localhost:3000 # create (returns slug + a one-time manageToken to edit/delete later) curl -s -X POST $BASE/docs \ -H 'Content-Type: application/json' \ -H 'X-Reach-Actor: planner-agent' \ -d '{"content":"# Onboarding checklist\n\n1. Create the account\n2. Grant access","visibility":"public","note":"init"}' # read raw source (what you hand an agent) curl -s "$BASE/d/?raw=1" # read the rendered page (what a person sees) curl -s "$BASE/d/" -H 'Accept: text/html' ``` The hosted reachpad.dev runs in open-create mode, so creating a document needs no token there. To gate creation on your own deploy, set `WRITE_TOKENS` and pass `Authorization: Bearer ` . Editing, deleting, and restoring a document always require that document's `manageToken` (or an operator `WRITE_TOKENS` bearer). Auth is **header-only**: `Authorization: Bearer ` (never the url). Attribute change-history entries with `X-Reach-Actor: ` . | Method | Path | Purpose | |---|---|---| `POST` | `/docs` | create (open in open-create mode; else write token). Returns one-time `manageToken` | `GET` | `/d/:slug` | read (negotiated: raw source / `?format=json` manifest / rendered HTML) | `GET` | `/d/:slug?raw=1` | raw source (markdown/HTML) | `GET` | `/d/:slug/v/:n` | a specific version | `PUT` | `/d/:slug` | edit, creates a new version (`If-Match: ` for safe simultaneous edits) | `PATCH` | `/d/:slug` | section-scoped edit (`X-Reach-Section` ; op `replace` /`append` /`prepend` ) | `DELETE` | `/d/:slug` | soft delete (recorded; restorable) | `POST` | `/d/:slug/restore` | undo a delete | `GET` | `/d/:slug/history` | full version + change history | `GET` | `/d/:slug/diff` | bounded unified diff between two versions (`?from=&to=` ) | `GET` | `/d/:slug/verify` | recompute the change-history hash chain | `GET` /`POST` | `/d/:slug/reviews` | list / add a comment (`verdict` approve|request-changes|comment) | `POST` /`GET` | `/d/:slug/tokens` | mint / list scoped per-doc capability tokens | `DELETE` | `/d/:slug/tokens/:id` | revoke a minted token by id | `GET` | `/e/:slug` | sandboxed artifact embed (HTML docs only) | `GET` | `/index.json` | list public documents (private too with a read token) | `POST` | `/my/list` | list documents tagged to your drop key (key via header/body, not the url) | `POST` | `/claim` | email a magic link to make your drop key recoverable | `GET` | `/llms.txt` , `/openapi.json` | machine-readable guide + spec | `GET` | `/health` , `/stats` | store status + public usage counts | Documents default to **unlisted** (reachable only with the link, never in `/index.json` ); `public` (listed for everyone) and `private` (link plus a read token) are explicit opt-ins. Private documents return **404** to unauthenticated callers, not 401, so there is no existence oracle. Per-doc capability tokens are scoped (`read` /`edit` /`manage` ), optionally expiring, and revocable, so you can hand a peer agent least-privilege access instead of the root `manageToken` . See `/openapi.json` for the complete surface. ``` # read raw, then edit the next version with safe simultaneous edits curl -s "$BASE/d/?raw=1" curl -s -X PUT "$BASE/d/" \ -H 'Authorization: Bearer ' \ -H 'If-Match: 1' -H 'Content-Type: application/json' \ -d '{"content":"# Onboarding checklist\n\n1. Create the account\n2. Grant access\n3. Send the welcome email","note":"add step"}' ``` reach exposes its API as MCP tools over a remote Streamable-HTTP endpoint at `https://reachpad.dev/mcp` (add that url to your agent) and ships the `@reachpad/mcp` npm package for stdio clients, with one-click setup at [ /connect](https://reachpad.dev/connect). See [.](/las7/reach/blob/main/mcp/README.md) `mcp/README.md` Tools: `list_docs` , `get_doc` , `get_doc_meta` , `get_history` , `verify_doc` , `get_diff` , `create_doc` (aka `share_doc` / `handoff_doc` ), `edit_doc` (aka `update_shared_doc` ), `edit_section` , `delete_doc` , `restore_doc` , the per-doc capability-token tools `mint_token` / `list_tokens` / `revoke_token` , the comment tools `list_comments` / `add_comment` , and `my_docs` (your drop-key library). ``` # point the local stdio server at any reach instance REACH_BASE_URL=https:// REACH_WRITE_TOKEN=... npm run mcp ``` A document can be a single-file HTML artifact (its own scripts, styles, canvas). Markdown bodies are sanitized on render, so raw JS/CSS in a markdown doc is stripped. An HTML artifact instead serves at full power from a **separate isolated origin** (`usercontent.reachpad.dev` ), so the agent's interactive page runs as built while staying structurally walled off from reach's API and your other documents. The same-origin `/e/:slug` embed is the sandboxed fallback when no artifact host is configured. **Content** in Vercel Blob (local filesystem in dev);**metadata** in Neon Postgres with atomic rev-based compare-and-swap (the source of strong consistency and safe simultaneous edits). Immutable version content always stays in Blob/FS.**Encrypted at rest**(AES-256-GCM,`REACH_CONTENT_KEY` ): a leaked storage url yields ciphertext, not content.**Tamper-evident hash-chained history.** Every operation appends an entry whose hash is an HMAC keyed by a server-only secret (`REACH_LEDGER_SECRET` , distinct from the content key) and chained off the previous entry, so a party with mere storage access cannot forge or rewrite history.`GET /d/:slug/verify` recomputes the chain and detects truncation, reordering, or insertion.**No code execution.** Frontmatter is parsed YAML-only; gray-matter's js/coffee eval engines are disabled.**Strict CSP with a per-request nonce**(`script-src 'self' 'nonce-...'` ), plus`nosniff` ,`frame-ancestors 'none'` (the sandboxed artifact embed uses`frame-ancestors 'self'` so only the doc wrapper may frame it),`Referrer-Policy: no-referrer` , HSTS. The raw view of an HTML doc is served as`text/plain` , so attacker HTML can never execute on reach's own origin; the live render is the isolated artifact origin.- Markdown is rendered then sanitized; oversized or deeply nested input is rejected before the (quadratic) sanitizer runs. - Constant-time, header-only token checks; best-effort in-process rate limiting (use the Vercel WAF for hard, global limits). Light, monospace (self-hosted Geist), monochrome, minimal. The site is small: the landing page at `/` , the app at `/home` (your documents + search + connect), `/browse` (public documents), and `/developers` (the API reference). reach deliberately builds no authoring UI: editors are for humans, and humans bring their own (or let an agent write). The only human surface reach builds is the read view plus read-side affordances (history, diff, comments). Zero-config Hono: `api/index.ts` exports the app. After `vercel link` : ``` vercel blob create-store reach-blob --access public --yes # content storage vercel env add REACH_CONTENT_KEY production # openssl rand -base64 32 vercel env add REACH_LEDGER_SECRET production # openssl rand -base64 32 (must differ from content key) vercel env add REACH_CLAIM_SECRET production # openssl rand -base64 32 (third independent secret; keys email claim links) vercel env add DATABASE_URL production # Neon pooled connection string vercel env add REACH_USE_NEON production # 1 to serve metadata from Postgres vercel env add ARTIFACT_HOST production # usercontent.reachpad.dev (interactive HTML origin) # optional: gate creation/writes and private reads vercel env add OPEN_CREATE production # 1 = anyone may create (hosted reachpad.dev runs this) vercel env add WRITE_TOKENS production vercel env add SHARE_TOKENS production # readers of private docs vercel env add ADMIN_TOKENS production # global audit surfaces (must be set explicitly) vercel env add REACH_LOOPBACK_SECRET production # openssl rand -hex 24 (recommended; skips rate-limiting internal /mcp self-fetches) vercel --prod ``` In production (`NODE_ENV=production` ) a missing `REACH_CONTENT_KEY` , `REACH_LEDGER_SECRET` , or `REACH_CLAIM_SECRET` is a hard error; there is no silent dev-key fallback, and the three secrets must all differ. `GET /health` reports the active store and whether writes are gated. Contributions welcome. MIT (see [ LICENSE](/las7/reach/blob/main/LICENSE); self-hosted Geist fonts under SIL OFL 1.1, see [).](/las7/reach/blob/main/LICENSE-fonts) `LICENSE-fonts` See [ CONTRIBUTING.md](/las7/reach/blob/main/CONTRIBUTING.md) before sending a change, [to report a vulnerability, and](/las7/reach/blob/main/SECURITY.md) `SECURITY.md` [for what changed.](/las7/reach/blob/main/CHANGELOG.md) `CHANGELOG.md` ``` api/index.ts Vercel entry (export default app) src/app.ts routes + middleware (auth, CSP, rate limit, body limit) src/repo.ts documents, versions, hash-chained change history src/meta.ts metadata backends (KvMeta over Blob/FS, PgMeta over Postgres) src/db.ts Neon connection + idempotent schema src/store.ts encrypted key/value over Blob or local FS src/render.ts markdown/HTML render + sanitize src/web.ts landing, home, browse, developers, doc pages, llms.txt, OpenAPI src/mcp-route.ts remote /mcp endpoint (Streamable HTTP) mcp/tools.ts shared MCP tool definitions (stdio + remote) mcp/server.ts stdio MCP server ```