sharedoc-mcp

Agent-generated Markdown → a link you can hand to anyone. GitHub gists today, your own server tomorrow.

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An MCP stdio server — works in Claude Code, Codex CLI, and any MCP client — that gives your agent 8 tools to publish, update, search, and revoke shareable documents. Two pluggable backends behind one interface: gist (zero setup, rides your logged-in gh CLI) and selfhost (SQLite on your machine, passwords, enforced expiry).

When a backend can't honor a parameter (e.g. password on gist), it returns a clear error instead of silently ignoring it.

Why?

AI agents produce Markdown constantly — reports, research digests, meeting notes. Getting that to another human usually means copy-pasting walls of text into a chat window.

Without sharedoc-mcp                  With sharedoc-mcp
────────────────────                  ─────────────────
copy a wall of text into chat         "share this as a doc"
paste again for each person           one link for everyone
content lives in chat scroll          revoke / extend / append later
"can you password it?"  …no           selfhost backend: bcrypt + expiry

Features

• ✓ 8 MCP tools: create / append / extend / reset password / rename / revoke / delete / search
• ✓ sharedoc-mcp serve daemon mode — selfhost links keep working after your MCP client closes
• ✓ Content search: find old share links by what's in them, not just the title
• ✓ GET /healthz — identity-aware health probe for external monitoring / restart automation
• ✓ Two backends, one interface — switch with a single env var, tool schemas stay identical
• ✓ Gist backend (default): secret gists via your logged-in gh CLI — no tokens to manage, nothing new to host
• ✓ Selfhost backend: docs stay on your machine (SQLite via built-in node:sqlite — zero native modules)
• ✓ Server-verified passwords (bcrypt) with rate-limited attempts — 5/minute, HTTP 429, counters persisted in SQLite so a restart can't reset them (selfhost)
• ✓ Enforced expiry (410) and revoke with a 7-day content-purge grace (selfhost); lazy expiry cleanup (gist)
• ✓ Markdown rendered through marked + sanitize-html — scripts, event handlers, and javascript: URLs in shared content are stripped
• ✓ Viewer binds 127.0.0.1 only, answers with a strict security-header set (CSP default-src 'none', nosniff, DENY framing, no-referrer, no-store) — exposure is a tunnel you control (recipes below)
• ✓ Local index for search_shared_docs + create dedup (identical unprotected retries within 5 min return the same URL; a retry that adds a password/expiry always creates a new doc)
• ✓ Two MCP clients can share one data dir: SQLite WAL + busy timeout, graceful port sharing
• ✓ 70 offline tests; npm test passes on a clean checkout

Install

Requires Node.js ≥ 22.13.0. Gist backend additionally needs GitHub CLI logged in (gh auth login).

Option A — Claude Code (one line):

claude mcp add sharedoc --scope user -- npx -y sharedoc-mcp@^2

Option B — Codex CLI (~/.codex/config.toml):

[mcp_servers.sharedoc]
command = "npx"
args = ["-y", "sharedoc-mcp@^2"]

Option C — any other MCP client: run npx -y sharedoc-mcp@^2 as a stdio server.

Why @^2? A bare npx -y sharedoc-mcp resolves the latest published version on every cold start — a future 3.0 could change behavior (or remove a tool) under you without warning. @^2 follows 2.x fixes but never crosses a breaking major; pin an exact version (@2.1.0) if you want zero drift.

Pick your backend

	🅰 gist (default)	🅱 selfhost
Setup	none — uses your logged-in gh CLI	none extra — data stays on your machine
Doc lives on	GitHub (secret gist)	your machine (SQLite)
Link reachable	anywhere, immediately	localhost — add a tunnel to share externally
Password	✗ (the secret URL is the protection)	✓ server-verified (bcrypt), rate-limited
Expiry	lazy — expired gists deleted on next use	enforced — expired links return 410
Revoke	gist deleted immediately, irreversibly	immediate 410, content purged after 7-day grace

Gist quickstart

Ask your agent to "share this as a doc" — it calls create_shared_doc and returns a secret gist URL. Secret gists are not listed publicly and the URL is unguessable, but anyone who has the link can read it — that's the whole security model of this backend. Need passwords? Use selfhost.

A local index (~/.config/sharedoc-mcp/index.json) tracks what you've shared, powering search and expiry cleanup. Expiry here is lazy: expired gists are deleted the next time any tool runs, not at the exact expiry moment.

Selfhost quickstart

claude mcp add sharedoc --scope user --env SHAREDOC_BACKEND=selfhost -- npx -y sharedoc-mcp@^2

Docs live in SQLite at ~/.local/share/sharedoc-mcp/; a viewer serves them at http://127.0.0.1:8377. To share beyond your machine, put a tunnel in front and set SHAREDOC_PUBLIC_URL:

Links that outlive your editor: in MCP mode the viewer dies with the MCP client — close Claude Code and selfhost links stop answering until the next session (data is safe in SQLite). Run the standalone daemon to keep links alive around the clock:

npx -y sharedoc-mcp@^2 serve   # viewer only, same DB — keep it running via launchd/systemd/tmux (Windows: Task Scheduler or NSSM)

MCP clients detect the daemon already owns the port and simply use it.

When to set this up: the moment you first hand a link to someone else — do it together with your tunnel (both should be long-running, e.g. under launchd/systemd). Until then the MCP-mode viewer is enough, and gist-backend users never need it.

Recipe	Fits you if	Setup
Tailscale private (recommended)	recipients are your own devices / people you can invite to your tailnet	tailscale serve --bg 8377 → https://<machine>.<tailnet>.ts.net, reachable only inside your tailnet — nothing is exposed to the public internet
Tailscale Funnel	share with anyone, no domain	tailscale funnel 8377 → same stable URL, but public
Cloudflare named tunnel	you own a domain	domain on Cloudflare, cloudflared tunnel create + route a hostname to http://127.0.0.1:8377
cloudflared quick tunnel	one-off sharing	cloudflared tunnel --url http://127.0.0.1:8377 → random URL, changes every restart

Own a domain? Cloudflare named tunnel, step by step

A branded, stable share URL like https://docs.example.com/docs/<uuid> — TLS handled by Cloudflare, works from behind NAT:

# one-time setup (domain already added to Cloudflare — the free plan is enough)
cloudflared tunnel login
cloudflared tunnel create sharedoc
cloudflared tunnel route dns sharedoc docs.example.com

~/.cloudflared/config.yml:

tunnel: sharedoc
credentials-file: ~/.cloudflared/<tunnel-id>.json
ingress:
  - hostname: docs.example.com
    service: http://127.0.0.1:8377
  - service: http_status:404

Run cloudflared tunnel run sharedoc (or install it as a service for always-on), and register the MCP server with the public URL:

claude mcp add sharedoc --scope user \
  --env SHAREDOC_BACKEND=selfhost \
  --env SHAREDOC_PUBLIC_URL=https://docs.example.com \
  -- npx -y sharedoc-mcp

Extras this unlocks: Cloudflare's DDoS protection comes free; you can layer WAF rules, or put Cloudflare Access (SSO) in front of everything except the share paths — an "SSO inside, password-protected shares outside" split.

Alternative — always-on without a home machine: run sharedoc-mcp on a VPS (where your agent also runs) and point nginx/caddy at 127.0.0.1:8377 with your domain and auto-TLS; no tunnel needed.

Environment variables:

Variable	Default	Meaning
SHAREDOC_BACKEND	gist	gist or selfhost
SHAREDOC_PORT	8377	viewer port (selfhost)
SHAREDOC_PUBLIC_URL	http://127.0.0.1:<port>	URL prefix in share links — set to your tunnel hostname
SHAREDOC_DATA_DIR	~/.local/share/sharedoc-mcp	SQLite location (selfhost)
SHAREDOC_INDEX_PATH	~/.config/sharedoc-mcp/index.json	local index (gist)
MCP_CALLER	—	default author attribution for created docs

The 8 tools

Tool	Does
create_shared_doc	title + Markdown (+ optional password / expires_in_hours / author) → share URL
append_to_shared_doc	append Markdown (not idempotent — a retry appends twice)
extend_shared_doc	extend expiry by N hours
reset_shared_doc_password	set / change / remove (null) the password (selfhost only)
update_shared_doc_title	rename
revoke_shared_doc	kill the link, keep the record (see backend table for semantics)
delete_shared_doc	kill the link AND erase the record — irreversible; requires confirm: true (agents should get explicit user approval first)
search_shared_docs	no args = list newest links; title substring, body-text search (selfhost: full content; gist: opening excerpt), status filter

Privacy

Data flow, by backend:

• Gist backend: your document content is uploaded to GitHub as a secret gist under your account — GitHub's terms and retention apply. The local index stays in ~/.config/sharedoc-mcp/ — it stores titles, URLs, timestamps, and the first 200 characters of each doc (for local content search); never the full content. Nothing is sent anywhere except GitHub via your own gh CLI.
• Selfhost backend: content never leaves your machine unless you attach a tunnel — then it's served to whoever you gave the link (and the tunnel provider relays the traffic). Passwords are stored only as bcrypt hashes.
• sharedoc-mcp itself has no telemetry and calls no third-party service of its own.

Security semantics, honestly

• Gist links are bearer tokens: anyone with the URL reads the doc. Revoke deletes the gist immediately and irreversibly.
• Selfhost passwords are verified server-side before content is served; only WRONG attempts are rate-limited (5/minute per source+doc; a correct unlock clears the counter), with counters persisted in SQLite — restarting the server does not reset them. Behind a tunnel, all external visitors share one source address, so the practical limit is 5/minute per doc — stricter than per-visitor; one person mistyping can briefly lock a doc for others.
• There is deliberately no file-sharing tool: an arbitrary-path "share this file" tool is a prompt-injection exfiltration vector (.env, keys) — a hijacked agent could publish secrets. Removed rather than allowlisted.
• The viewer never binds beyond 127.0.0.1. Whether and how it reaches the internet is entirely your tunnel's configuration.

Develop

git clone https://github.com/AugustusW/sharedoc-mcp.git
cd sharedoc-mcp
npm install
npm test        # builds, then runs 70 offline tests — gh CLI is mocked, HTTP tests hit 127.0.0.1 only

Versioning: every release bumps version in package.json, adds a CHANGELOG entry, and is published as a git tag + GitHub Release + npm. To get update notifications: Watch this repo (Custom → Releases). npx -y fetches the latest published version on each cold run; your index and docs DB live outside the package — updating never touches them.

Status

v2.1.0 (CHANGELOG) — core logic is covered by 70 offline unit/integration tests (the gh CLI is mocked; HTTP tests run against 127.0.0.1 only; no network needed). The full flows have been manually verified (2026-07-25: real secret-gist create/index/delete via the built server over stdio JSON-RPC, and the selfhost password flow end-to-end — form → wrong password 401 → correct password 200 → rate-limit 429 → revoke 410 — plus lsof confirmation of the 127.0.0.1-only bind) on:

• macOS (Apple Silicon), Node v25 — gist + selfhost backends

Tunnel recipes are documented from the tools' standard behavior; Windows/Linux and real-tunnel end-to-end runs have not yet been verified — reports welcome.

License

MIT © AugustusW