| name | record-demo |
| description | Record or regenerate the mcpc demo GIFs (the README hero docs/images/mcpc-demo.gif and the focused tapes in docs/vhs/) with VHS. Use whenever asked to create, refresh, restyle, shorten, or fix a terminal demo/animation/GIF of mcpc. The tapes drive real mcpc commands; for the authenticated step this skill ALWAYS prompts for a short-lived, low-permission TEST token first (never production). Captures the VHS + mcpc gotchas learned the hard way — read it fully before editing a tape. |
| allowed-tools | Bash, Read, Write, Edit, AskUserQuestion |
record-demo: VHS demo GIFs for mcpc
The tapes in docs/vhs/*.tape are VHS
scripts that drive a real shell session — VHS types each command, runs it
against a live MCP server, captures the terminal, and renders a GIF. The README
hero is docs/images/mcpc-demo.gif, built from docs/vhs/mcpc-demo.tape.
This file is the accumulated know-how. Read all of it before touching a tape
— most rules below were discovered by hitting the wall, and skipping them wastes
whole render cycles (~1–2 min each).
The hero flow (mcpc-demo.tape)
A basic-use story across both transports:
mcpc — empty state (no sessions, no profiles)
mcpc connect mcp.json:filesystem — local stdio server (auto-names @filesystem)
mcpc — session list (now shows the live session)
mcpc @filesystem tools-list
mcpc @filesystem tools-list --json — JSON output, syntax-highlighted, no jq
mcpc connect mcp.apify.com -H "Authorization: Bearer $APIFY_TOKEN" — remote HTTP server (auto-names @apify)
mcpc @apify tools-list
mcpc @apify tools-get search-actors — inspect one tool's input schema
mcpc @apify tools-call search-actors keywords:="web scraper" limit:=3
mcpc @apify close
Ten commands run ~45s; there is no hard 30s cap for this flow.
Style conventions (the current standard — match these)
VHS gotchas (these will bite you)
- ASCII prompt symbols only. Multibyte glyphs (
❯, », ▶) break bash prompt
rendering under VHS and show up as garbage like 92m]. Use $ (or >), styled
with color + bold.
Type quoting: use single quotes around any command containing double
quotes. A \" inside a double-quoted Type breaks VHS's parser. e.g.
Type 'mcpc @apify tools-call search-actors keywords:="web scraper" limit:=3'
and Type 'export PS1="\[\e[…m\]$\[\e[0m\] "'.
- Output/Screenshot paths: must not start with a digit (
Output 1-foo.gif
fails to parse) and must not be long absolute paths (the parser chokes). Use
short, letter-leading, relative names and run vhs from docs/vhs/.
Screenshot is unreliable (frequently exits 2 even though the GIF rendered
fine). Don't depend on it — pull frames from the finished GIF instead:
ffmpeg -y -ss <seconds> -i x.gif -vframes 1 frame.png, then Read the PNG.
- Renders are slow (~1–2 min each: real-time timeline + Chromium + ffmpeg
encode). Render tapes one at a time — a
for loop over several blows the
5-minute command timeout. Extracted frames often land mid-typing; sample a few
timestamps around when output should be on screen.
- Hidden connects leak into the recording if bash falls behind. When a tape
connects in the hidden setup (so the feature commands run against a ready
session, e.g. tools/scripting/grep), a slow connect lets VHS type ahead; bash
then echoes the buffered commands and runs the
clear after Show, so the
setup spills into frame. Pattern that works: type the connect(s), then one
generous Sleep (7–8s) so they finish, then clear, then another Sleep
(~1.5s) before Show. (Tapes that connect visibly as their first command
don't need this — their hidden setup is just fast exports + clear.)
Stdio servers in a headless / proxied box
npx-launched stdio servers are too slow here. npx -y <pkg>'s registry
round-trip exceeds mcpc's 60s connect handshake, so connect times out
(MCP error -32001). Fixes: pre-install the server (npm i -g <pkg>) and put
the direct binary in mcp.json (e.g. mcp-server-filesystem, starts in
~0.3s — also a cleaner session header), or use npx --prefer-offline -y <pkg>
once the npm cache is warm (~5s; plain npx -y still does the slow registry
check even when cached).
- Puppeteer does NOT work for headless recording.
@modelcontextprotocol/server-puppeteer launches Chromium eagerly on startup
and hangs/times out as root in the container. Use
@modelcontextprotocol/server-filesystem instead (14 recognizable tools,
instant). docs/vhs/mcp.json defines the filesystem entry via its global
binary — install it first: npm i -g @modelcontextprotocol/server-filesystem.
Auth token (the authenticated step)
- Always prompt for the token first. Insist on a short-lived,
low-permission token from a TEST / throwaway account — never production.
Apify: https://console.apify.com/settings/integrations. Tell the user to
revoke it as soon as the recording is done.
- Pass it inline, for the render only:
APIFY_TOKEN=… vhs mcpc-demo.tape. The
tape references $APIFY_TOKEN (never the literal), typed inside single
quotes so bash expands it at run time — the value is never on screen, never
in the GIF, never committed. Always verify a connect frame shows
$APIFY_TOKEN, not the value.
connect auto-names the session: mcp.apify.com → @apify,
mcp.json:filesystem → @filesystem. No @name needed.
- No-token alternative (public, anonymous):
mcpc connect "https://mcp.apify.com/?tools=search-actors,fetch-actor-details,docs".
Keychain warning (headless only)
On a box with no keyring, the bearer-token connect prints
[keychain] OS keychain unavailable, falling back to file-based credential storage …. It is environment-specific (won't appear on a normal desktop
with a keyring) and there is no env var to suppress it — it's a logger.warn
in src/lib/auth/keychain.ts gated only by keychain availability and JSON mode.
A dbus-run-session + gnome-keyring-daemon wrapper does not fix it in this
sandbox (raising the dbus fd limit is blocked). Options: leave it (honest), or add
a targeted 2>/dev/null to just that one connect command.
Prerequisites
mcpc --version
vhs --version
mcp-server-filesystem
Headless + root: VHS drives a Chromium (go-rod auto-downloads it to
~/.cache/rod) that refuses to start without --no-sandbox. If renders fail to
launch Chromium, wrap the binary once:
CHROME=$(find ~/.cache/rod/browser -name chrome -type f | head -1)
mv "$CHROME" "$CHROME-real"
printf '#!/bin/sh\nexec "$(dirname "$0")/chrome-real" --no-sandbox --disable-gpu --disable-dev-shm-usage "$@"\n' > "$CHROME"
chmod +x "$CHROME"
(Run vhs once first to trigger the Chromium download.)
Render and verify
cd docs/vhs
APIFY_TOKEN=… vhs mcpc-demo.tape
ffprobe -v error -show_entries format=duration -of csv=p=0 mcpc-demo.gif
ffmpeg -y -ss 12 -i mcpc-demo.gif -vframes 1 /tmp/f.png
cp mcpc-demo.gif ../images/mcpc-demo.gif
Check each frame class: empty state, stdio connect + session list, tools-list,
JSON, remote connect (token NOT visible), tool-call result, close. Then
revoke the token.
Optimize the GIF size (do this before committing)
VHS GIFs are large (the hero is ~5 MB raw). Shrink them losslessly-ish with
gifsicle (kornel.ski/lossygif) — --lossy
drops imperceptible inter-frame detail and cuts ~60% off a text-terminal GIF
with no visible quality loss:
for f in docs/images/mcpc-demo.gif docs/vhs/*.gif; do
[ "$f" = docs/vhs/mcpc-demo.gif ] && continue
gifsicle -O3 --lossy=200 -b "$f"
done
After optimizing, re-extract a colored frame (ffmpeg -ss 12 …) and eyeball it —
lossy=200 is the sweet spot; going much higher smears the antialiased text.
When the optimized hero lands on main, bump the README cache-buster
(mcpc-demo.gif?v=N → ?v=N+1): GitHub's camo image proxy caches by full URL,
so a new ?v= is what makes it re-fetch the smaller file instead of serving the
old cached copy.
What's committed
docs/images/mcpc-demo.gif — the README hero (canonical copy).
docs/vhs/*.gif — the per-feature recordings are committed too, so they're easy
to find and reuse. .gitignore ignores only docs/vhs/mcpc-demo.gif (the hero's
raw output, since it's committed under docs/images/).
proxy.gif needs a token to record and isn't committed until recorded.
The tapes
| Tape | Records |
|---|
mcpc-demo.tape | Hero basic-use flow (stdio + remote) → docs/images/mcpc-demo.gif |
quickstart.tape | Minimal connect → list → call |
tools.tape | tools-list / tools-get / tools-call, inline JSON, stdin |
scripting.tape | --json piped through jq (code mode) |
grep.tape | Dynamic tool discovery with mcpc grep across two sessions (Apify + filesystem) |
proxy.tape | MCP proxy / AI sandboxing (keeps a bearer token on purpose) |
All focused tapes follow the same conventions as the hero (bold $ prompt,
bold-white commands, no comments, blank-line separation, mktemp home).
quickstart/tools/scripting/grep are token-free (public ?tools= URL);
grep also connects a local filesystem stdio server so it can search across two
sessions. proxy.tape keeps a bearer token because demonstrating that you can
proxy a credentialed session without leaking the token is its entire point (it's
the one focused tape that needs a token to record).