mempalace: drop the stage ENV pin, fix the shared-server compose

The feeder now defaults to <palace-root>/pi-stage upstream, so pinning
MEMPALACE_PI_STAGE into ~/.pi here is unnecessary -- and was actively wrong. It
created a second convention that could still diverge from the palace: keep the
devbox-palace volume, drop devbox-pi-config, and a scoped `mempalace sync`
prunes every conversation drawer, because dedup keys on the staged path. Both
the ENV and the entrypoint export are gone; a comment explains why adding one
back re-introduces the split it was meant to fix.

docker-compose.mempalace.yml was broken on mempalace 3.6.0 in both directions:
  - `--host 0.0.0.0` with no token in the environment makes the server refuse
    to start, crash-looping under `restart: unless-stopped`.
  - Supply a token and the healthcheck's unauthenticated `tools/list` POST 401s,
    marking a perfectly healthy server unhealthy forever.
Now the token is required via ${MEMPALACE_REMOTE_TOKEN:?...} so it fails fast at
`docker compose up` with a readable message, and the healthcheck probes the
deliberately token-free /healthz. The "no authentication of its own" security
note has been stale since 3.6.0 and is replaced with the actual posture
(bearer token + Host pin + Origin allowlist), including why browser-shaped auth
must not be put in front of it.

Dockerfile.base: mempalace-pi-session symlinked onto PATH, with a build-time
`--help` check so a broken feeder fails the image build rather than the first
session.

smoke-test: assert the stage resolves beside the palace (default, and following
$MEMPALACE_PALACE_PATH) instead of asserting the removed ENV pin. The two
behavioural guards -- a synthetic session that must be captured, an abandoned
one that must not be -- are unchanged.

.env.example: recommend `mempalace serve` on the docker0 gateway rather than
`mempalace-mcp --transport http --host 0.0.0.0`, with the two binds to avoid.

.env.example

@@ -12,16 +12,59 @@ SSH_KEY_PATH=~/.ssh
 # ── MemPalace memory (local by default) ───────────────────────────
 # By default the mempalace.ts extension spawns a LOCAL mempalace-mcp stdio
 # server (palace at ~/.mempalace). Uncomment the devbox-palace volume in
-# docker-compose.yml to persist it across container recreation.
+# docker-compose.yml to persist it across container recreation — that one
+# volume now covers the mined conversation transcripts too, since the pi and
+# opencode feeders stage inside the palace root (<palace-root>/pi-stage), so
+# the staged files and the palace dedup keys pointing at them cannot be
+# separated.
 #
 # To instead share ONE MemPalace across containers/harnesses (pi + opencode
 # + native), set the URL below. When set, the extension connects over HTTP
 # and NO local mempalace-mcp is spawned; the devbox-palace volume is then
 # irrelevant. MEMPALACE_REMOTE_TOKEN, if set, is sent as a bearer token.
-#   Serve it with:  mempalace-mcp --transport http --host 0.0.0.0 --port 8765
-# MEMPALACE_REMOTE_URL=http://mempalace.lan:8765/mcp
+#
+#   Serve it with:  mempalace serve --host 172.17.0.1 --port 8765
+#
+# NOT `mempalace-mcp --transport http --host 0.0.0.0`: `serve` is the turnkey
+# wrapper that mints/keeps a bearer token (0600, passed via env so it stays out
+# of `ps`) and can terminate TLS. Two binds to avoid:
+#   0.0.0.0    - exposes the palace to the whole LAN.
+#   127.0.0.1  - behind a tunnel this 403s every proxied request (the Host pin
+#                is only enforced on loopback binds) AND silently starts with
+#                no token at all, since auto-minting is gated on the bind being
+#                non-loopback. Bind the docker0 gateway: reachable from the host
+#                and its containers (so a newt/proxy container works), not from
+#                the LAN. Set MEMPALACE_MCP_HTTP_TOKEN explicitly server-side.
+# MEMPALACE_REMOTE_URL=https://mempalace.example.com/mcp
 # MEMPALACE_REMOTE_TOKEN=
 
+# ── MemPalace: automatic capture of pi sessions ───────────────────────
+# The mempalace.ts extension feeds this container's pi transcripts into the
+# palace by itself: on session_shutdown, and on a debounced agent_settled so a
+# crash loses at most one window rather than the whole session. The entrypoint
+# also runs a catch-up at container start, which is the only thing that can
+# recover transcripts after a hard kill (no handler runs on SIGKILL).
+# Nothing below is required for the local-palace case; the defaults work.
+#
+# MEMPALACE_FEED=0                    # disable automatic capture entirely
+# MEMPALACE_FEED_DEBOUNCE_MS=600000   # min gap between mid-session feeds (10 min)
+# MEMPALACE_FEED_WING=wing_conversations
+#
+# REMOTE PALACE ONLY (MEMPALACE_REMOTE_URL set above): the palace is on another
+# host, and `mempalace_mine` resolves its source path in the SERVER process, so
+# the server cannot see this container's transcripts. The feeder therefore
+# rsyncs its staged exports into a per-device inbox on the palace host and asks
+# the server to mine its own local copy. Without MEMPALACE_PI_SSH_TARGET the
+# feeder is skipped (a remote palace with no inbox has nothing to mine).
+#   MEMPALACE_PI_SSH_TARGET  where to rsync to, as user@host:path
+#   MEMPALACE_PI_REMOTE_PATH what that inbox is called ON THE SERVER — must be
+#                            the container path if the server runs in Docker
+#                            (see docker-compose.mempalace.yml)
+#   MEMPALACE_PI_DEVICE      inbox subdirectory for this machine (default: hostname)
+# MEMPALACE_PI_SSH_TARGET=user@palace-host:/srv/mempalace-feed
+# MEMPALACE_PI_REMOTE_PATH=/data/feed
+# MEMPALACE_PI_DEVICE=
+
 # ── LAN access from the container (host-OS-agnostic) ─────────────────
 # On VM-backed hosts (macOS OrbStack / Docker Desktop) the container can't
 # reach the host's directly-attached LAN peers by default. The entrypoint

CHANGELOG.md

@@ -11,6 +11,82 @@ Pre-v1.0.0 tags followed the pi npm version (`v{pi_version}[letter]`).
 
 ---
 
+## Unreleased
+
+Minor-shaped. Headline: **pi sessions now feed MemPalace by themselves.** The
+image already shipped `mempalace-toolkit`, but its pi feeder
+(`mempalace-pi-session`) was never symlinked onto `PATH`, so nothing ever mined
+pi's transcripts — the palace only ever contained what an agent remembered to
+file by hand. A container that gets recreated regularly has no other memory, so
+a missed wind-down was a permanently lost session.
+
+*Why event-driven and not a timer:* there is nothing schedulable inside the
+container — PID 1 is `bash -l`, with no systemd and no cron — and anything
+installed would not survive recreate anyway. The triggers therefore live where
+the events already are: pi's own lifecycle, plus container start.
+
+### Added
+
+- **`mempalace-pi-session` symlinked onto `PATH`** (`Dockerfile.base`,
+  alongside its `mempalace-session` / `mempalace-docs` siblings, with the same
+  `--help` build-time check). `entrypoint-user.sh` also self-heals the symlink
+  into `~/.local/bin` (already ahead of `/usr/local/bin` on `PATH`, and
+  writable by `developer`) so the feature works on images whose base predates
+  this change.
+- **Container-start catch-up feed** (`entrypoint-user.sh`, backgrounded). pi's
+  mempalace extension feeds the palace on `session_shutdown` and on a debounced
+  `agent_settled`, but a hard kill (`docker kill`, OOM, host reboot) runs no
+  handler at all; this is the only trigger that can recover the previous life's
+  transcripts. Skipped when a remote palace is configured without an inbox to
+  ship to, and skippable entirely with `MEMPALACE_FEED=0`.
+- **`MEMPALACE_PI_STAGE` no longer needs pinning here — the feeder's default
+  was fixed upstream instead.** It used to stage under `~/.cache`, which is
+  disposable in a container; the first cut of this change pinned the env var
+  into the persisted `~/.pi` volume. That was the wrong fix: it created a second
+  convention that could still diverge from the palace (keep the palace volume,
+  drop `devbox-pi-config`, and a scoped `mempalace sync` prunes every
+  conversation drawer, because dedup keys on the *staged* path). The feeder now
+  defaults to `<palace-root>/pi-stage`, resolved with mempalace's own
+  precedence (`$MEMPALACE_PALACE_PATH` → `$MEMPAL_PALACE_PATH` →
+  `~/.mempalace/config.json` → `~/.mempalace/palace`), so the stage inherits
+  whatever persistence the palace has and the two cannot be separated by
+  accident. No `ENV` and no entrypoint export: adding one back would
+  re-introduce exactly the split it removes.
+- **Transcript inbox mount in `docker-compose.mempalace.yml`**
+  (`${MEMPALACE_FEED_DIR:-./feed}:/data/feed:ro`). A client cannot mine into a
+  remote palace directly: `mempalace_mine` expands its source path in the
+  *server* process, so the server can only see paths inside its own container.
+  Clients rsync their staged exports to a per-device subdirectory and then ask
+  the server to mine `/data/feed/<device>`. Read-only because mining only reads
+  sources — all locks live palace-side.
+- **Smoke tests** for the above: `mempalace-pi-session` on `PATH`, two
+  assertions that the stage resolves next to the palace (default, and following
+  `$MEMPALACE_PALACE_PATH`), and two behavioural guards that feed the exporter a
+  synthetic pi session — one that must be captured, one abandoned session that
+  must not be. The second matters because pi expands skills/context into the
+  user prompt, so an abandoned session can look substantial by byte count while
+  containing no assistant output; and if pi's JSONL shape ever changes, the
+  exporter would silently capture nothing.
+- **`.env.example`**: documents `MEMPALACE_FEED`,
+  `MEMPALACE_FEED_DEBOUNCE_MS`, `MEMPALACE_FEED_WING`, and the remote-palace
+  shipping vars `MEMPALACE_PI_SSH_TARGET`, `MEMPALACE_PI_REMOTE_PATH`,
+  `MEMPALACE_PI_DEVICE`.
+
+### Notes
+
+- The `Dockerfile.base` change moves the base hash, so this needs a base
+  rebuild; the `~/.local/bin` self-heal exists so the feature does not have to
+  wait for one.
+- Requires the matching `mempalace-toolkit` change (`--prepare` two-phase
+  split, remote transport, and the auto-feed triggers in
+  `extensions/pi/mempalace.ts`). The split exists because the palace is
+  single-writer: a live pi session holds it through the extension's own
+  `mempalace-mcp`, so a CLI `mempalace mine` during a session fails with
+  "palace ... is held by PID". Staging is therefore done by the CLI and the
+  mine itself by whichever process already holds the palace.
+
+---
+
 ## v1.7.0 — 2026-08-07
 
 Minor release. Headline: **pi-atelier is now part of the image** — the TUI

Dockerfile.base

@@ -424,9 +424,12 @@ RUN if [ "${INSTALL_MEMPALACE}" = "true" ] && [ "${INSTALL_MEMPALACE_TOOLKIT}" =
       [ "$ok" = "1" ] && \
       ln -sf /opt/mempalace-toolkit/bin/mempalace-session /usr/local/bin/mempalace-session && \
       ln -sf /opt/mempalace-toolkit/bin/mempalace-docs    /usr/local/bin/mempalace-docs && \
-      chmod +x /opt/mempalace-toolkit/bin/mempalace-session /opt/mempalace-toolkit/bin/mempalace-docs && \
+      ln -sf /opt/mempalace-toolkit/bin/mempalace-pi-session /usr/local/bin/mempalace-pi-session && \
+      chmod +x /opt/mempalace-toolkit/bin/mempalace-session /opt/mempalace-toolkit/bin/mempalace-docs \
+               /opt/mempalace-toolkit/bin/mempalace-pi-session && \
       mempalace-session --help >/dev/null && \
       mempalace-docs    --help >/dev/null && \
+      mempalace-pi-session --help >/dev/null && \
       echo "mempalace-toolkit installed at $(cd /opt/mempalace-toolkit && git rev-parse --short HEAD)" ; \
     fi
 

docker-compose.mempalace.yml

@@ -5,6 +5,7 @@
 # Point every client at it by setting, in that client's .env:
 #
 #   MEMPALACE_REMOTE_URL=http://<reachable-host>:8765/mcp
+#   MEMPALACE_REMOTE_TOKEN=<the shared bearer token>
 #
 # (see .env.example). When set, the client connects over HTTP and does NOT
 # spawn its own local mempalace-mcp.
@@ -18,12 +19,21 @@
 # (both are pinned by the same image build). Override with a slimmer image via
 # MEMPALACE_SERVER_IMAGE if you prefer (it must provide `mempalace-mcp`).
 #
-# ⚠ SECURITY: mempalace-mcp's HTTP transport has NO authentication of its own.
-# Do NOT expose port 8765 to an untrusted network. The default below binds to
-# 127.0.0.1 (host loopback) only. To let sibling containers reach it, either
-# attach them to the shared `mempalace-net` network (container-to-container, no
-# host port needed — use http://mempalace-server:8765/mcp), or front it with a
-# reverse proxy that enforces MEMPALACE_REMOTE_TOKEN as `Authorization: Bearer`.
+# ⚠ SECURITY: the HTTP transport IS authenticated as of mempalace 3.6.0 — an
+# earlier version of this comment said otherwise and was wrong. The server
+# compares `Authorization: Bearer <token>` with hmac.compare_digest and
+# **refuses to start on a non-loopback bind without a token**, so
+# MEMPALACE_REMOTE_TOKEN below is required, not optional: without it this
+# service crash-loops. It also pins `Host` and allowlists `Origin`.
+#
+# Still do not publish port 8765 to an untrusted network. The default binds to
+# 127.0.0.1 (host loopback) only. To let sibling containers reach it, attach
+# them to the shared `mempalace-net` network (container-to-container, no host
+# port needed — use http://mempalace-server:8765/mcp). To reach it from
+# elsewhere, terminate TLS in a tunnel/reverse proxy and let the bearer token be
+# the authentication — do NOT add browser-shaped auth (SSO/PIN/password) in
+# front, because every MCP client here is a headless JSON-RPC POST and would
+# receive a login page where JSON should be.
 
 name: mempalace-server
 
@@ -40,6 +50,11 @@ services:
     user: "0:0"
     environment:
       - HOME=/data
+      # Required: mempalace refuses a non-loopback bind without a token (it
+      # would exit at startup and, with restart:unless-stopped, crash-loop).
+      # `:?` fails fast at `docker compose up` with a readable message instead.
+      # Clients send the same value as MEMPALACE_REMOTE_TOKEN.
+      - MEMPALACE_MCP_HTTP_TOKEN=${MEMPALACE_REMOTE_TOKEN:?set MEMPALACE_REMOTE_TOKEN in .env — the shared palace requires a bearer token}
     command:
       - mempalace-mcp
       - --transport
@@ -60,16 +75,28 @@ services:
       - mempalace-shared:/data/.mempalace
       # Embedding-model cache (~79 MB, disposable) so search does not re-download.
       - mempalace-shared-chroma:/data/.cache/chroma
+      # Transcript inbox. Clients cannot mine into a remote palace directly:
+      # `mempalace_mine` expands its source path in THIS process, so it can only
+      # see paths inside this container. Each client rsyncs its staged session
+      # exports to a per-device subdirectory on the host (see
+      # MEMPALACE_PI_SSH_TARGET in .env.example) and then calls mempalace_mine
+      # with the container-side path below (MEMPALACE_PI_REMOTE_PATH=/data/feed).
+      # Read-only: mining only reads sources, and all locks live palace-side.
+      - ${MEMPALACE_FEED_DIR:-./feed}:/data/feed:ro
     networks:
       - mempalace-net
     healthcheck:
-      # A tools/list round-trip proves the server is answering MCP (python3 is
-      # always present — mempalace itself is a python tool in the image).
+      # GET /healthz, which is Host/Origin-gated but deliberately token-free —
+      # so this probe needs no credentials. Do NOT go back to POSTing
+      # `tools/list` here: that carries no Authorization header and now 401s,
+      # marking a perfectly healthy server unhealthy forever. The Host pin is
+      # only enforced on loopback *binds* (this one is 0.0.0.0), so a request to
+      # 127.0.0.1 inside the container passes.
       test:
         - CMD
         - python3
         - -c
-        - "import urllib.request,json; d=json.dumps({'jsonrpc':'2.0','id':1,'method':'tools/list','params':{}}).encode(); r=urllib.request.Request('http://127.0.0.1:8765/mcp',data=d,headers={'Content-Type':'application/json','Accept':'application/json'}); urllib.request.urlopen(r,timeout=5).read()"
+        - "import urllib.request,sys; sys.exit(0 if urllib.request.urlopen('http://127.0.0.1:8765/healthz',timeout=5).status==200 else 1)"
       interval: 30s
       timeout: 10s
       retries: 3

entrypoint-user.sh

@@ -92,6 +92,56 @@ if command -v mempalace &>/dev/null && [ -d /workspace ]; then
   fi
 fi
 
+# ── MemPalace: pi transcript feeder ─────────────────────────────────
+# mempalace-toolkit ships `mempalace-pi-session`, which mines pi's own JSONL
+# session transcripts into the palace. pi's mempalace extension drives it on
+# session_shutdown and on a debounced agent_settled; this is the catch-up for
+# the one case no handler can cover — a hard kill (docker kill, OOM, host
+# reboot) runs nothing at all, so without this the previous life's transcripts
+# are never mined.
+#
+# No MEMPALACE_PI_STAGE override here on purpose: the feeder stages next to the
+# palace it feeds (<palace-root>/pi-stage), so the stage and the dedup keys
+# referencing it share one lifetime — whatever persistence the palace has, the
+# stage inherits. Pinning it elsewhere (e.g. into the ~/.pi volume) would
+# re-introduce the very split that design prevents: palace volume kept, stage
+# volume dropped, and `mempalace sync` then prunes every conversation drawer.
+#
+# Backgrounded: a cold mine can take tens of seconds and must never delay the
+# shell. Contention with a live session is handled by the tool itself (it exits
+# 0 and lets the palace holder do the mine).
+
+# Self-heal onto PATH for images whose base predates the toolkit symlink.
+# ~/.local/bin is already ahead of /usr/local/bin on PATH (Dockerfile.base sets
+# it in ENV PATH) and is writable by this (non-root) user, unlike /usr/local/bin.
+if [ -x /opt/mempalace-toolkit/bin/mempalace-pi-session ] && \
+   ! command -v mempalace-pi-session >/dev/null 2>&1; then
+  mkdir -p "$HOME/.local/bin"
+  ln -sf /opt/mempalace-toolkit/bin/mempalace-pi-session "$HOME/.local/bin/mempalace-pi-session"
+fi
+
+# Resolve the feeder explicitly rather than trusting PATH: this runs before any
+# login shell, and a silently-skipped catch-up is exactly the failure we are
+# here to prevent.
+MEMPALACE_FEEDER=""
+if command -v mempalace-pi-session >/dev/null 2>&1; then
+  MEMPALACE_FEEDER="mempalace-pi-session"
+elif [ -x /opt/mempalace-toolkit/bin/mempalace-pi-session ]; then
+  MEMPALACE_FEEDER="/opt/mempalace-toolkit/bin/mempalace-pi-session"
+fi
+
+if [ "${MEMPALACE_FEED:-1}" != "0" ] && [ -n "$MEMPALACE_FEEDER" ]; then
+  if [ -n "${MEMPALACE_REMOTE_URL:-}" ] && [ -z "${MEMPALACE_PI_SSH_TARGET:-}" ]; then
+    : # remote palace but no inbox configured — nothing we can ship to; skip quietly
+  else
+    mkdir -p "$HOME/.pi/agent"
+    (
+      "$MEMPALACE_FEEDER" --reason container-start \
+        >"$HOME/.pi/agent/mempalace-catchup.log" 2>&1 || true
+    ) &
+  fi
+fi
+
 # ── Git config defaults ──────────────────────────────────────────────
 if [ -n "${GIT_USER_NAME:-}" ] && ! git config --global user.name &>/dev/null; then
   git config --global user.name "$GIT_USER_NAME"

scripts/smoke-test.sh

@@ -91,6 +91,59 @@ run "terminfo: modern emulators (ncurses-term)" 'for t in wezterm alacritty foot
 run "terminfo: xterm-ghostty alias (tic)" "infocmp -x xterm-ghostty >/dev/null 2>&1"
 run "nvim true-colour default (sysinit.vim)" "nvim --headless -c 'lua os.exit(vim.o.termguicolors and 0 or 1)'"
 run "mempalace-mcp"   "mempalace-mcp --help"
+run "mempalace-pi-session on PATH" "mempalace-pi-session --help"
+# The staging dir must sit next to the palace, not in a disposable cache: the
+# palace keys per-source dedup on the STAGED path, so a stage that can be wiped
+# while the palace survives lets `mempalace sync` prune every drawer mined from
+# it. Assert the resolved default, not an env var — the guarantee is "stage
+# shares the palace's lifetime", which an ENV pin would quietly break.
+# NOTE: --sessions-dir gets an EMPTY temp dir, never /tmp. The stage banner is
+# printed before any export, so nothing needs to be found — and pointing a
+# default-staged run at a populated dir would export whatever transcripts it
+# finds into the real stage, which is how a synthetic test session ends up
+# staged for mining as if it were a real conversation.
+run "pi stage defaults next to the palace (not a cache dir)" '
+  out=$(mempalace-pi-session --dry-run --reason smoke --sessions-dir "$(mktemp -d)" 2>&1) || true
+  echo "$out" | grep -q "stage=/home/developer/.mempalace/pi-stage/"
+'
+run "pi stage follows MEMPALACE_PALACE_PATH" '
+  out=$(MEMPALACE_PALACE_PATH=/tmp/alt/.mempalace/palace \
+        mempalace-pi-session --dry-run --reason smoke --sessions-dir "$(mktemp -d)" 2>&1) || true
+  echo "$out" | grep -q "stage=/tmp/alt/.mempalace/pi-stage/"
+'
+# Regression guard for the pi transcript exporter. If pi ever changes its
+# session JSONL shape, the exporter stops recognising sessions and the palace
+# silently gets nothing (or, worse, raw JSON chunked as prose). Feed it a
+# synthetic session and assert it is actually exported. Uses --dry-run so no
+# palace is touched, and a temp stage so nothing real is written.
+run "pi transcript exporter recognises a pi session" '
+  set -e
+  d=$(mktemp -d); s="$d/sessions/--workspace--"; mkdir -p "$s"
+  {
+    printf "%s\n" "{\"type\":\"session\",\"version\":1,\"id\":\"smoke\",\"cwd\":\"/workspace\",\"timestamp\":\"2026-01-01T00:00:00Z\"}"
+    printf "%s\n" "{\"type\":\"message\",\"message\":{\"role\":\"user\",\"content\":\"question one\"}}"
+    a=$(printf "a%.0s" $(seq 1 1200))
+    printf "%s\n" "{\"type\":\"message\",\"message\":{\"role\":\"assistant\",\"content\":[{\"type\":\"text\",\"text\":\"$a\"}]}}"
+    printf "%s\n" "{\"type\":\"message\",\"message\":{\"role\":\"user\",\"content\":\"question two\"}}"
+    printf "%s\n" "{\"type\":\"message\",\"message\":{\"role\":\"assistant\",\"content\":[{\"type\":\"text\",\"text\":\"short reply\"}]}}"
+  } > "$s/2026-01-01T00-00-00-000Z_smoke.jsonl"
+  out=$(mempalace-pi-session --dry-run --sessions-dir "$d/sessions" --stage "$d/stage" 2>&1)
+  echo "$out" | grep -q "Exported 1 session"
+'
+# The same guard from the other side: a session with no real assistant output
+# (an abandoned prompt, whose bulk is injected skill text) must NOT be filed.
+run "pi transcript exporter rejects an abandoned session" '
+  set -e
+  d=$(mktemp -d); s="$d/sessions/--workspace--"; mkdir -p "$s"
+  {
+    printf "%s\n" "{\"type\":\"session\",\"version\":1,\"id\":\"smoke2\",\"cwd\":\"/workspace\",\"timestamp\":\"2026-01-01T00:00:00Z\"}"
+    u=$(printf "u%.0s" $(seq 1 13000))
+    printf "%s\n" "{\"type\":\"message\",\"message\":{\"role\":\"user\",\"content\":\"$u\"}}"
+    printf "%s\n" "{\"type\":\"message\",\"message\":{\"role\":\"assistant\",\"content\":[{\"type\":\"text\",\"text\":\"Ready. What would you like to work on?\"}]}}"
+  } > "$s/2026-01-01T00-00-00-000Z_smoke2.jsonl"
+  out=$(mempalace-pi-session --dry-run --sessions-dir "$d/sessions" --stage "$d/stage" 2>&1)
+  echo "$out" | grep -q "no sessions qualified"
+'
 # v1.0.0 base additions — verify presence and basic functionality.
 run "pandoc"          "pandoc --version"
 run "typst"           "typst --version"