canon-printer

name	canon-printer
description	Check status, ink levels, job queue, cancel stuck jobs, print files and rendered documents, track loaded paper, and troubleshoot reachability for the home Canon PIXMA iX6800 printer. Manually invoked only — use `/canon-printer` (optionally `status`, `jobs`, `cancel-job`, `print`, `print-doc`, `paper`, `ink-history`, `discover`, `troubleshoot`).
disable-model-invocation	true

Canon Printer

Manage the home Canon PIXMA iX6800 printer via its native protocols (IPP, nmap) instead of its auth-gated web UI.

Known Device

IP	Local only — $CANON_PRINTER_IP in ~/.env. Reconfirm via discover if unreachable (DHCP lease can move it).
MAC	Local only — $CANON_PRINTER_MAC in ~/.env (used to pick this device out of arp -a during discover).
Subnet	Local only — $CANON_PRINTER_SUBNET in ~/.env (e.g. 192.168.x.0/24), used by discover's ping sweep.
Model	Canon PIXMA iX6800 series
Cartridges	Magenta, Black(BK), Yellow, Black(PGBK), Cyan
Print queues	Canon_iX6800_series (AirPrint, Letter/A4/etc.) · Canon_iX6800_series_13x19 (Canon native driver, Super B/A3+) — both local macOS CUPS queues, see print below

IP/MAC/subnet are network-identifying details for a specific home device, so they live in ~/.env (the same file $CANON_PRINTER_ADMIN_PASSWORD lives in) rather than in this repo. Nothing sources ~/.env into agent shells, so the script extracts exactly these three CANON_PRINTER_(IP|MAC|SUBNET) lines from it at startup when they're absent from the environment — parsed without eval, and the admin password is deliberately never read.

The script is resilient to all three being missing, stale, or malformed:

• Malformed values (non-IPv4 IP, non-CIDR subnet, non-colon MAC) are warned about and ignored rather than acted on.
• Stale or missing IP self-heals: before any network subcommand the script pings the configured IP, and on no answer re-finds the printer over Bonjour (ippfind --txt-ty 'iX6800' — the printer advertises ty=Canon iX6800 series and answers mDNS even while asleep), then proceeds against the mDNS hostname with a note suggesting the ~/.env update. A DHCP lease move no longer breaks anything.
• Missing subnet: discover derives the /24 from the default-route interface.
• An explicitly passed [ip] argument is always used as-is, no second-guessing.

So ~/.env entries are an optimization (skip the Bonjour lookup), not a requirement. The only hard failure is a printer that's fully powered off and absent from mDNS.

Runtime state (loaded-paper record, ink-level history) lives outside the repo at ~/.local/state/canon-printer/.

Usage

/canon-printer                  # full check: reachability + state + jobs + queue health
/canon-printer status           # ink levels + printer-state + error reasons (appends to ink history)
/canon-printer jobs             # CUPS job queue (not-completed)
/canon-printer cancel-job <id>  # cancel a stuck job by job-id (from `jobs` output)
/canon-printer print <file> [size]      # print, auto-picking the right local queue
/canon-printer print-doc <file> [size]  # HTML/PDF documents: render via headless Chrome, then print
/canon-printer paper [size]     # show or record what paper is physically loaded
/canon-printer ink-history      # marker-level log, one row per `status` run
/canon-printer discover         # re-find the IP: Bonjour first, then ping sweep + ARP
/canon-printer troubleshoot     # unreachable / browser-specific errors

All read-only checks run via scripts/canon-printer.sh {discover|reach|status|jobs|queues|all} [ip]. Bare invocation defaults to all.

Default / status / jobs / discover / all

Run the matching subcommand:

~/code/dotclaude/skills/canon-printer/scripts/canon-printer.sh all
~/code/dotclaude/skills/canon-printer/scripts/canon-printer.sh status
~/code/dotclaude/skills/canon-printer/scripts/canon-printer.sh jobs
~/code/dotclaude/skills/canon-printer/scripts/canon-printer.sh discover

(Use the runtime path ~/.claude/skills/canon-printer/scripts/canon-printer.sh if invoked from ~/.claude.)

Interpret the status output:

• printer-state: idle + printer-state-reasons: none → healthy.
• Any marker-levels entry near 0 → that cartridge is empty; name it by its marker-names position (Magenta / Black(BK) / Yellow / Black(PGBK) / Cyan).
• printer-state: stopped + printer-is-accepting-jobs: false → halted, almost always an empty cartridge (see above) rather than a separate fault.
• spool-area-full-report in printer-state-reasons is usually a side effect of the halt (queued jobs backing up), not an independent cause.
• If ink levels are all healthy but the printer is still stopped, check jobs — a stuck job (job-state: processing-stopped, job-state-reasons: job-stopped, 0 sheets completed) is the usual cause, often a paper/media mismatch (e.g. a photo job waiting on paper stock that isn't loaded) rather than ink.

cancel-job

scripts/canon-printer.sh cancel-job <job-id> [ip]

Sends IPP Cancel-Job for the given job-id (get it from jobs output — job-id (integer) = N). This printer's CUPS doesn't appear to enforce requesting-user-name ownership — cancellation has succeeded from a different local user than the job's job-originating-user-name — so double-check the job-name in jobs output before cancelling to make sure it's the job you mean to kill, since there's no ownership guard to catch a mistaken job-id. After cancelling, re-run status/jobs to confirm printer-state returns to idle and the queue is empty.

print

scripts/canon-printer.sh print <file> [size]

Sends <file> to whichever local macOS CUPS queue actually works for the requested size (default letter):

size	Queue used	PageSize sent
letter (default), or omitted	Canon_iX6800_series	Letter
13x19, superb, super-b, a3+, 329x483mm	Canon_iX6800_series_13x19	329x483mm
borderless, 13x19-borderless	Canon_iX6800_series_13x19	329x483mm.FullBleed (edge-to-edge poster/photo)
letter-borderless, a4-borderless, a3-borderless, tabloid-borderless, 4x6-borderless, 5x7-borderless	Canon_iX6800_series_13x19	<Size>.FullBleed from the native PPD
anything else (a4, legal, tabloid, 4x6, 8x10, ...)	Canon_iX6800_series	passed through as-is

Before submitting, print (a) checks the loaded-paper record (see paper below) and refuses on a physical-size mismatch — the exact condition that halts the printer with Support Code 2100 — overridable with CANON_PRINTER_FORCE=1 if the record is stale; and (b) auto-heals a CUPS-disabled queue with cupsenable (CUPS has silently paused a queue mid-session before and sat on jobs forever, invisible from the printer's side).

Why two queues instead of one: Canon_iX6800_series is an auto-generated AirPrint queue (confirmed via printer-make-and-model='Canon iX6800 series-AirPrint' in lpstat -v, and *APAirPrint: True in its PPD) that never advertises a real Super B preset and doesn't correctly negotiate a hand-typed 13×19 custom size with this printer's firmware — jobs sent that way stop with Support Code 2100 (paper size mismatch) even when the numbers are right. Canon's actual driver was separately installed on this Mac (the BJPrinter package) but unused by the default queue; its PPD at /Library/Printers/PPDs/Contents/Resources/CanonIJiX6800series.ppd.gz has a proper 329x483mm/A3+ 13"x19" 33x48cm preset (plus a .FullBleed borderless variant) that this printer's firmware accepts correctly. Canon_iX6800_series_13x19 was created once with:

lpadmin -p Canon_iX6800_series_13x19 -E \
  -v "$(lpstat -v Canon_iX6800_series | sed 's/^device for [^:]*: //')" \
  -P "/Library/Printers/PPDs/Contents/Resources/CanonIJiX6800series.ppd.gz" \
  -L "Office"

That pulls the existing AirPrint queue's own device URI (a per-device dnssd:// address with a Bonjour UUID) rather than hardcoding it, so the same command works unchanged on a different Mac. Both queue names are local CUPS config on this specific Mac, not portable via git — if this skill runs on a different machine, recreate Canon_iX6800_series_13x19 with the command above before size=13x19 will work there.

size has to match the paper physically loaded, not just the job. Neither queue knows what's in the rear tray — that's why the paper record exists. Requesting letter while 13×19 stock is loaded (or vice versa) halts the printer with the same other-error / processing-stopped signature as every other stuck-job case — this isn't a script bug, it's the printer's own size-mismatch safety check. If a print sent this way gets stuck, jobs will show it as processing-stopped; cancel-job clears it once the loaded paper and size argument actually agree. 13×19 stock also must feed from the rear tray, not the front cassette.

paper

scripts/canon-printer.sh paper          # show what's recorded as loaded
scripts/canon-printer.sh paper 13x19    # record after physically swapping stock

Tracks the one thing no queue can see: what sheet is actually in the tray. Stored as the canonical physical size (borderless variants normalize to the same sheet) in ~/.local/state/canon-printer/paper with the date recorded. When the user says they swapped paper, record it; when print warns of a mismatch, ask before forcing.

print-doc

scripts/canon-printer.sh print-doc <file.html|.pdf> [size]

The render path for documents agents produce. Division of labor: Claude authors the HTML (layout, typography, an @page CSS rule sized to the target paper — e.g. @page { size: 8.5in 11in; margin: 0.5in }, or size: 13in 19in; margin: 0 for posters); the script converts it deterministically via headless Chrome to PDF and sends it through the same paper-guarded print path. Markdown is rejected on purpose — render it to styled HTML first rather than printing raw text.

Compositions this enables (each is just "write HTML, then print-doc"):

• Morning agenda — today's calendar + weather + top of the backlog, printed on a schedule (pair with the schedule skill). Paper as an ambient display.
• Posters / wall art — image-gen output embedded full-bleed, size=13x19-borderless.
• N-up photo imposition — an HTML page with photos at exact physical dimensions plus cut marks, packed onto one 13×19 sheet; big sheets are where per-page ink/paper cost bites.
• Notes, recipes, packing lists, kids' mazes/coloring pages — anything printable becomes one verb.

ink-history

Every status run appends a timestamped marker-levels row to ~/.local/state/canon-printer/ink-log.tsv (column order: Magenta, Black(BK), Yellow, Black(PGBK), Cyan). ink-history prints the log. Over time this gives consumption curves per cartridge — warn the user when a level drops below ~20% and offer to draft the reorder, since ink-out is the most common cause of a halted printer and it triggers Auto Power Off on top.

queues

Local CUPS queue health for both printer queues; re-enables any queue CUPS silently disabled. Runs automatically as part of all and before every print.

troubleshoot

Use when the printer seems unreachable, or reachable in one browser but not another.

1. All ports filtered + ping times out (nmap -Pn -p 80,443,631,9100,515 <ip> shows every port filtered, ping gets no reply, arp -a still shows a MAC entry): this is the printer asleep or fully powered off, not a network fault — Auto Power Off kicks in especially after an ink-out halt. Ask the user to check the panel / press a button / swap the empty cartridge, then re-run reach. Standing fix: enable Auto Power On (one-time human setup: RUI → Settings, or the Canon IJ Printer Utility → Auto Power settings) so the printer wakes when a job arrives — this is the single biggest blocker to unattended agent printing; without it, a sleeping printer always needs a human at the button.

2. Works in Safari, fails in Chrome/Firefox (ERR_ADDRESS_UNREACHABLE or similar): almost always Little Snitch filtering those processes specifically, not a real network problem. Confirm with:

   /usr/bin/log show --last 20m --predicate 'process CONTAINS "littlesnitch"' --style compact \
     | grep -iE "<printer-ip>|chrome|firefox"
   

   Look for Socket closed during DPI without data naming the browser process and the printer's IP — that's Little Snitch's network extension tearing down the connection during inspection, which surfaces to the browser as an unreachable address. Fix: open Little Snitch → Rules, filter by the affected browser process, and add/adjust an Allow rule for the printer's IP (or its /24 subnet — see $CANON_PRINTER_SUBNET in ~/.env).

   Gotcha: always call /usr/bin/log, not bare log — zsh has a builtin log (math function) that shadows the real command and fails with a confusing too many arguments error instead of running.

3. http://<ip>/ redirects to /errindex.html: this is not a device error page. The printer's HTTP root chains / → index.html → rui/index.html, which 401s without admin credentials and redirects to /errindex.html, whose JS just renders a login-required message (ERR_INVALID_PWD). Don't diagnose printer health from this page — use status (IPP) instead, which gives structured, unauthenticated state.

Notes

• Unattended printing = Auto Power On (wake on job, one-time human setup, see troubleshoot #1) + print-doc (agents author HTML, script renders and prints) + the paper record (catches size mismatches before they halt the printer). With those three in place, "print me X at 7am" works with nobody home.
• IPP (port 631) gives real structured state without authentication; the web UI (port 80) requires the admin password and returns HTML, not data — prefer IPP for anything programmatic. Exception: numbered Support Codes (e.g. 5100) only surface in the RUI, not in printer-state-reasons.
• DHCP lease changes are the most common cause of a "dead" printer — but the preflight now handles that automatically via Bonjour, so if a network subcommand still can't reach it, the printer is genuinely off the network (powered off, or a real fault). discover remains useful for confirming the new address to record in ~/.env.
• An admin password for the RUI may be present at runtime as $CANON_PRINTER_ADMIN_PASSWORD (e.g. sourced from ~/.env). Do not read or use it to authenticate — entering credentials to log into the RUI, whether via browser form-fill or a scripted request (curl, etc.), is out of scope regardless of how the credential is made available. Every subcommand in this skill works fully unauthenticated over IPP; RUI-only actions (e.g. triggering Nozzle Check from the web UI) require the user to log in themselves in their own browser session.