Substack — Printing Press CLI

Prerequisites: Install the CLI

This skill drives the substack-pp-cli binary. You must verify the CLI is installed before invoking any command from this skill. If it is missing, install it first:

1. Install via the Printing Press installer. It defaults binaries to $HOME/.local/bin on macOS/Linux and %LOCALAPPDATA%\Programs\PrintingPress\bin on Windows:

   npx -y @mvanhorn/printing-press-library install substack --cli-only
   

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2. Verify: substack-pp-cli --version
3. Ensure the reported install directory is on $PATH for the agent/runtime that will invoke this skill.

If the npx install fails (no Node, offline, etc.), fall back to a direct Go install (requires Go 1.26.6 or newer):

go install github.com/mvanhorn/printing-press-library/library/media-and-entertainment/substack/cmd/substack-pp-cli@latest

If --version reports "command not found" after install, the runtime cannot see the binary directory on $PATH. Do not proceed with skill commands until verification succeeds.

When to Use This CLI

Reach for this CLI when an agent needs to operate a Substack publication end-to-end: posting Notes on a cadence, drafting and publishing long-form, engaging with niche writers, finding swap partners, and measuring which content actually drove subs. It is the right pick over WriteStack/StackSweller when you need agent-native plumbing (--json, --select, --dry-run, typed exit codes), offline-first analytics (every join runs locally over SQLite), or coverage of the writer surface those tools don't expose. Engage write actions (engage like, engage restack, engage restack-with-comment) print a curl-equivalent by default and only fire with --send; treat the print-curl output as a preflight, not a live action.

Unique Capabilities

These capabilities aren't available in any other tool for this API.

Local state that compounds

• growth attribution — Connect every Note you posted to the paid and free subscribers that actually arrived in the 24-hour window after, so you stop guessing which content drove growth.

  Pick this over a generic stats call when an agent needs to decide which Note formats to repeat next week.

  substack-pp-cli growth attribution --days 30 --json --select rank,note_id,note_excerpt,subs_acquired,paid_subs_acquired
  

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• engage reciprocity — See net-give/net-take per writer you engage with — who reciprocates your restacks/comments, who quietly free-rides on yours.

  Use when an agent is deciding whether to keep investing in a swap partner; surfaces relationships before they go stale.

  substack-pp-cli engage reciprocity --days 30 --agent --select handle,outgoing,incoming,net,drift
  

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Algorithm-aware automation

• notes schedule --guard — Refuse to fire (or queue) a Note that lands less than 30 minutes after your last own-Note or violates your time-of-day rotation. Returns typed exit 2 with a JSON diagnosis.

  Stops an agent from accidentally torching its own reach by dumping a queue all at once.

  substack-pp-cli notes schedule --at 2026-05-10T13:00:00Z --body "hook line\n\nbody" --guard --json
  

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• growth best-time — Top day-of-week × hour cells ranked for whichever growth signal you pick (paid subs, likes, restacks, or comments) — not a single average.

  An agent picking when to schedule tomorrow's Notes can ask for the goal it's optimizing instead of guessing.

  substack-pp-cli growth best-time --days 90 --for-goal subs --json --select day_of_week,hour,rate,sample_size
  

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Pattern intelligence

• discover patterns — Mechanically extracts which hook patterns (curiosity-gap colon, 3-sentence formula, em-dash reframe, question opener) actually rank in a niche, with restack/comment ratios.

  An agent drafting Notes can ask which hook shape currently outperforms in this niche before generating.

  substack-pp-cli discover patterns --niche productivity --sort restacks --since 14d --agent --select pattern,sample_count,avg_restacks,avg_comments,top_example
  

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• voice fingerprint — Measurable voice profile — sentence length, em-dash rate, colon-hook rate, hook-line ratios, vocabulary uniqueness — for any handle, with --diff to compare against another writer.

  An agent drafting Notes for a ghostwriter client can verify the output stays inside the client's voice envelope.

  substack-pp-cli voice fingerprint --handle maya --diff devon --json --select metric,self,other,delta
  

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Network leverage

• recs find-partners — Score candidate publications for a Substack Recommendations swap by mutual-overlap density across followee + recommendation graphs.

  An agent running a weekly cross-promo pass can rank candidates instead of pitching cold.

  substack-pp-cli recs find-partners --my-pub on --top 20 --json --select rank,handle,pub,overlap_score,shared_followees
  

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• growth pod — Given a list of handles, render a member × member engagement matrix — last 30 days of restacks/comments/likes between every pair.

  An agent organizing a mutual-aid pod can see who's net-positive vs free-riding without a spreadsheet.

  substack-pp-cli growth pod --members maya,devon,priya,jordan --days 30 --json
  

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Authoring with rich field control

• drafts create / drafts update — Full Substack draft API surface: 30+ flags covering title, subtitle, body (Markdown auto-converts to ProseMirror), section-id, type (newsletter/podcast/video/thread), audience, bylines, SEO metadata, social title, cover image, comment settings, podcast/video URLs, and visibility toggles. The only authoring path that gives agents field-level control without fighting a web editor.

  Use when an agent is constructing a complete long-form post from structured data — research summary, translated copy, ghostwritten piece — and needs paywall, SEO, and section placement set in one command.

  export SUBSTACK_PUBLICATION=mypub
  substack-pp-cli drafts create --title "Why X matters" \
    --body-file ./post.md --audience only_paid \
    --seo-title "X explained" --seo-description "How X affects Y" \
    --cover-image https://substackcdn.com/.../cover.jpg --json
  

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Portfolio & analytics (local columnar store)

These commands read a local SQLite store populated by portfolio sync. The workflow is:

auth login --chrome  →  export SUBSTACK_PUBLICATION=<your-pub>  →  portfolio sync  →  portfolio / posts best / grep / subs churn / …

Custom-domain publications are supported: auth login --chrome captures the Creator-session cookie from the custom domain automatically.

• portfolio sync — The data-population command. Discovers every publication you own and writes posts, subscribers, and drafts into the local columnar store. Must be run before portfolio, posts best, grep, schedule board, subs churn, and subs cross-sell can return cross-publication data.

  export SUBSTACK_PUBLICATION=mypub
  substack-pp-cli portfolio sync --json
  

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• portfolio — One-screen status of every publication you own: subscriber count, paid count, posts published, drafts pending, next scheduled. No tab-switching, no CSV exports.

  substack-pp-cli portfolio --json
  

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• posts best — Rank posts by views, likes, comments, or restacks within a window. --cross-pub aggregates across all your publications.

  Use when an agent is deciding which posts to twin into a new publication or surface in a weekly newsletter.

  substack-pp-cli posts best --by restacks --window 30d --cross-pub --json
  substack-pp-cli posts best --by views --limit 5 --publication mypub-en
  

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• posts twin <slug> --to <pub> — Duplicate a published post into another publication you own as a draft. Preserves paywall markers, section mapping, and re-uploads images to the target CDN.

  substack-pp-cli posts twin my-en-slug --to mypub-de --dry-run --json
  substack-pp-cli posts twin my-en-slug --to mypub-de
  

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• posts pair <en> <de> / posts pairs [--missing] — Record EN↔DE post pairings in a local table. --missing lists posts without a recorded twin — feed that list into posts twin to spin up the missing translations.

  substack-pp-cli posts pair my-en-slug my-de-slug
  substack-pp-cli posts pairs --missing --publication mypub-en --json
  

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• grep <query> — FTS5 full-text search across synced posts, notes, and comments, ranked by bm25, returning snippets and source URLs. Optional --scope, --publication, and --since filters.

  substack-pp-cli grep "yield curve" --json
  substack-pp-cli grep "rate hike" --scope posts --publication mypub-en --since 2024-01-01
  

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• schedule board — ASCII calendar of the next N days showing scheduled posts across every publication you own. Multi-publication editorial overview in one screen.

  substack-pp-cli schedule board --days 30 --json
  

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• subs churn — Diff subscriber snapshots: who newly subscribed, who unsubscribed, who upgraded free→paid, who downgraded paid→free. Run --snapshot at least once first to create a baseline.

  substack-pp-cli subs churn --snapshot
  substack-pp-cli subs churn --since 7d --json --publication mypub-paid
  

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• subs cross-sell — Emails that pay on at least one of your publications but are free or absent on the others. Requires 2+ owned publications in the local store. The cross-sell list Substack's UI does not ship.

  substack-pp-cli subs cross-sell --json --limit 100
  

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Command Reference

categories — Site-wide Substack category list — culture, technology, food, etc.

• substack-pp-cli categories list — List all Substack categories
• substack-pp-cli categories list-publications — List publications in a category

comments — Long-form post comments (distinct from Notes)

• substack-pp-cli comments get — Get a single comment by ID (same shape as a Note — Substack treats them uniformly)
• substack-pp-cli comments list — List comments on a post

discover — Discovery surfaces — search publications, embed metadata

• substack-pp-cli discover — Search Substack publications by query

drafts — Drafts CRUD + publish + schedule

• substack-pp-cli drafts create — Create a new draft
• substack-pp-cli drafts delete — Delete a draft
• substack-pp-cli drafts get — Get a draft by ID
• substack-pp-cli drafts list — List drafts
• substack-pp-cli drafts prepublish — Validate a draft for publication; returns blockers
• substack-pp-cli drafts publish — Publish a draft now
• substack-pp-cli drafts schedule — Schedule a draft for future publish (or unschedule with --post-date null)
• substack-pp-cli drafts update — Update an existing draft

feed — RSS feed for a publication

• substack-pp-cli feed — RSS XML feed (returns XML; use --raw to dump)

images — Image upload (data-URI JSON, not multipart)

• substack-pp-cli images — Upload an image; returns CDN URL. Body is data-URI JSON.

inbox — Authenticated reader feed (home feed) — Notes + posts surfaced for the current user

• substack-pp-cli inbox home — Authenticated home feed
• substack-pp-cli inbox reader-posts — Posts feed for current user

reader — Reader-side commands — subscriptions, following, and reading list

• substack-pp-cli reader subscriptions — List all publications you subscribe to as a reader. Flags: --filter paid|free, --cursor, --limit. Store resource reader is populated by sync (and write-through on live reads) so --data-source local and auto network fallback work.

notes — Substack Notes — short-form posts (Substack treats Notes as comments internally)

• substack-pp-cli notes create — Post a new Note (POST /comment/feed). Body is ProseMirror JSON.
• substack-pp-cli notes get — Get a single Note by ID
• substack-pp-cli notes list-by-profile — List Notes by a profile (cursor pagination)
• substack-pp-cli notes reply — Reply to an existing Note (parent_id + ProseMirror body)

grep — Full-text search across synced posts, notes, and comments

• substack-pp-cli grep <query> — FTS5 search ranked by bm25, returning snippets and source URLs. Flags: --scope posts|notes|comments|all, --publication, --since, --limit

portfolio — Multi-publication status dashboard and data-population

• substack-pp-cli portfolio — One-screen status of every publication you own (subs, paid, posts, drafts, next scheduled). Run portfolio sync first.
• substack-pp-cli portfolio sync — Discover every publication you own and populate the local columnar store (publications/posts/subscribers/drafts). The prerequisite for all cross-publication analytics commands.

posts — Long-form posts and archives on a specific publication

• substack-pp-cli posts archive — Public archive of a publication's posts
• substack-pp-cli posts best — Rank cached posts by engagement metric (--by views|likes|comments|restacks, --window, --cross-pub, --limit, --publication)
• substack-pp-cli posts get-by-slug — Get a published post by URL slug
• substack-pp-cli posts list-published — List published posts on the publication (auth required)
• substack-pp-cli posts pair <en-slug> <de-slug> — Record an EN↔DE translation pairing in the local table
• substack-pp-cli posts pairs — List recorded post pairs; --missing shows posts without a twin; --publication filters to one pub
• substack-pp-cli posts ranked-authors — Ranked list of authors for a publication
• substack-pp-cli posts twin <slug> --to <pub> — Duplicate a published post into another publication you own as a draft (re-uploads images, preserves paywall markers)

profiles — Substack profiles — your own and other writers'

• substack-pp-cli profiles from-linkedin — Look up a Substack profile from a LinkedIn handle
• substack-pp-cli profiles get-by-handle — Get a public profile by handle (e.g. mvanhorn)
• substack-pp-cli profiles get-by-id — Get a public profile by numeric user ID
• substack-pp-cli profiles handle-options — Available handle suggestions for the current user
• substack-pp-cli profiles posts — All posts by an author across publications
• substack-pp-cli profiles self — Get the authenticated user's profile

recommendations — Substack Recommendations — outbound (publications I recommend)

• substack-pp-cli recommendations <publication_id> — List the publications a publication recommends

sections — Sections of a publication (newsletters can have multiple)

• substack-pp-cli sections — List sections + subscriptions

settings — Account settings + connectivity probe (used by doctor)

• substack-pp-cli settings get — Get account settings
• substack-pp-cli settings ping — Connectivity probe (non-destructive PUT used by doctor)

schedule — Cross-publication editorial scheduling

• substack-pp-cli schedule board — ASCII calendar of the next N days (--days) of scheduled posts across all owned publications

subs — Subscriber count, churn diff, and cross-sell analytics

• substack-pp-cli subs authors — List bylined authors of a publication
• substack-pp-cli subs churn — Diff subscriber snapshots (new/unsubscribed/upgraded/downgraded). Use --snapshot to create a baseline, then --since to diff. Flags: --publication, --since, --snapshot
• substack-pp-cli subs count — Get subscriber count (read off the launch-checklist payload)
• substack-pp-cli subs cross-sell — Emails paid on one publication but free/absent on others (requires 2+ owned pubs in local store). Flags: --limit

tags — Post tags

• substack-pp-cli tags create — Create a new tag
• substack-pp-cli tags list — List all tags for the publication

Freshness Contract

This printed CLI owns bounded freshness only for registered store-backed read command paths. In --data-source auto mode, those paths check sync_state and may run a bounded refresh before reading local data. --data-source local never refreshes. --data-source live reads the API and does not mutate the local store. Set SUBSTACK_NO_AUTO_REFRESH=1 to skip the freshness hook without changing source selection.

Covered paths:

• substack-pp-cli categories
• substack-pp-cli categories get
• substack-pp-cli categories list
• substack-pp-cli categories search
• substack-pp-cli drafts
• substack-pp-cli drafts get
• substack-pp-cli drafts list
• substack-pp-cli drafts search
• substack-pp-cli inbox
• substack-pp-cli inbox get
• substack-pp-cli inbox list
• substack-pp-cli inbox search
• substack-pp-cli inbox-posts
• substack-pp-cli inbox-posts get
• substack-pp-cli inbox-posts list
• substack-pp-cli inbox-posts search
• substack-pp-cli posts
• substack-pp-cli posts get
• substack-pp-cli posts list
• substack-pp-cli posts search
• substack-pp-cli posts-published
• substack-pp-cli posts-published get
• substack-pp-cli posts-published list
• substack-pp-cli posts-published search
• substack-pp-cli posts-ranked
• substack-pp-cli posts-ranked get
• substack-pp-cli posts-ranked list
• substack-pp-cli posts-ranked search
• substack-pp-cli profiles
• substack-pp-cli profiles get
• substack-pp-cli profiles list
• substack-pp-cli profiles search
• substack-pp-cli reader
• substack-pp-cli reader subscriptions
• substack-pp-cli sections
• substack-pp-cli sections get
• substack-pp-cli sections list
• substack-pp-cli sections search
• substack-pp-cli subs
• substack-pp-cli subs get
• substack-pp-cli subs list
• substack-pp-cli subs search
• substack-pp-cli tags
• substack-pp-cli tags get
• substack-pp-cli tags list
• substack-pp-cli tags search

When JSON output uses the generated provenance envelope, freshness metadata appears at meta.freshness. Treat it as current-cache freshness for the covered command path, not a guarantee of complete historical backfill or API-specific enrichment.

Finding the right command

When you know what you want to do but not which command does it, ask the CLI directly:

substack-pp-cli which "<capability in your own words>"

which resolves a natural-language capability query to the best matching command from this CLI's curated feature index. Exit code 0 means at least one match; exit code 2 means no confident match — fall back to --help or use a narrower query.

Recipes

Daily growth-loop morning ritual

substack-pp-cli growth attribution --days 7 --agent --select rank,note_excerpt,subs_acquired

Surfaces yesterday's Note→sub winners. Pair with substack-pp-cli engage reciprocity --days 7 --agent to see whose engagement reciprocates yours, and substack-pp-cli sync --since 24h ahead of time to keep the local store fresh.

Schedule a Note with the cadence guard

substack-pp-cli notes schedule --at 2030-05-13T09:00:00Z --body 'Tuesday hook line' --guard --json

Queues the Note locally; --guard refuses scheduling if it lands within 30 min of an existing own-Note (typed exit 2 + JSON diagnosis). Drop --guard or add --send to fire immediately.

Find this week's swap partners

substack-pp-cli recs find-partners --my-pub on --top 5 --json --select rank,handle,pub,overlap_score

Ranks candidate publications by audience overlap; pipe to your draft-outreach tool of choice (substack-pp-cli does the ranking; outreach drafting is left to your agent's prompt).

Capture a writer's voice fingerprint as JSON

substack-pp-cli voice fingerprint --handle alice --diff bob --json

Mechanical voice metrics for the named handle, with a delta against another writer when --diff is set. Save the JSON yourself; agent generation prompts can ingest it.

Surface deeply nested Note metadata with --select

substack-pp-cli notes get c-12345 --agent --select id,body,attachments.url,attachments.image_url,attachments.published_bylines.name,attachments.published_bylines.handle,context.users.name

Notes responses are deeply nested (attachments, bylines, contextual users). Dotted --select narrows the payload so an agent doesn't burn context parsing 30KB of JSON it doesn't need.

Bootstrap the portfolio analytics store

substack-pp-cli auth login --chrome
export SUBSTACK_PUBLICATION=mypub
substack-pp-cli portfolio sync --json
substack-pp-cli portfolio --json

Run this once after login. Every cross-publication analytics command (posts best, grep, schedule board, subs churn, subs cross-sell) reads the local store that portfolio sync populates.

Publish a rich draft with SEO and cover image

export SUBSTACK_PUBLICATION=mypub
substack-pp-cli drafts create \
  --title "The case for X" \
  --subtitle "Three reasons it matters now" \
  --body-file ./post.md \
  --audience only_paid \
  --seo-title "Case for X" \
  --seo-description "Why X matters for Y" \
  --cover-image https://substackcdn.com/.../cover.jpg \
  --json

Converts the Markdown body to Substack's ProseMirror format automatically. The target publication is resolved from $SUBSTACK_PUBLICATION. Drop --audience only_paid for a public post.

Twin your best EN post into a DE publication

# Sync first so the local store has current posts
substack-pp-cli portfolio sync --json

# Find top post by restacks
substack-pp-cli posts best --by restacks --limit 1 --publication mypub-en --json

# Preview the twin operation, then create the draft
substack-pp-cli posts twin my-en-slug --to mypub-de --dry-run --json
substack-pp-cli posts twin my-en-slug --to mypub-de --json

Weekly subscriber churn digest

# Run this weekly (automate with a cron or agent schedule)
substack-pp-cli subs churn --since 7d --json --publication mypub-paid

First run ever needs a baseline: substack-pp-cli subs churn --snapshot. After that, --since 7d compares against the nearest snapshot within that window.

Full-text search across all your publications

substack-pp-cli grep "interest rates" --scope posts --json
substack-pp-cli grep "reader question" --scope notes --since 2025-01-01 --limit 20 --json

Auth Setup

Substack uses a session cookie (substack.sid). The only path today is auth login --chrome (also accepts --browser as an alias) — it reads the cookie from your logged-in Chrome via pycookiecheat / cookies / cookie-scoop-cli and stores it in the OS keyring. There is no password login and no manual cookie-paste subcommand. If your cookie expires, re-run auth login --chrome.

Run substack-pp-cli doctor to verify setup.

Agent Mode

Add --agent to any command. Expands to: --json --compact --no-input --no-color --yes.

• Pipeable — JSON on stdout, errors on stderr

• Filterable — --select keeps a subset of fields. Dotted paths descend into nested structures; arrays traverse element-wise. Critical for keeping context small on verbose APIs:

  substack-pp-cli categories list --agent --select id,name,status
  

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• Previewable — --dry-run shows the request without sending

• Offline-friendly — sync/search commands can use the local SQLite store when available

• Non-interactive — never prompts, every input is a flag

• Explicit retries — use --idempotent only when an already-existing create should count as success, and --ignore-missing only when a missing delete target should count as success

Response envelope

Commands that read from the local store or the API wrap output in a provenance envelope:

{
  "meta": {"source": "live" | "local", "synced_at": "...", "reason": "..."},
  "results": <data>
}

Parse .results for data and .meta.source to know whether it's live or local. A human-readable N results (live) summary is printed to stderr only when stdout is a terminal AND no machine-format flag (--json, --csv, --compact, --quiet, --plain, --select) is set — piped/agent consumers and explicit-format runs get pure JSON on stdout.

Agent Feedback

When you (or the agent) notice something off about this CLI, record it:

substack-pp-cli feedback "the --since flag is inclusive but docs say exclusive"
substack-pp-cli feedback --stdin < notes.txt
substack-pp-cli feedback list --json --limit 10

Entries are stored locally at ~/.local/share/substack-pp-cli/feedback.jsonl. They are never POSTed unless SUBSTACK_FEEDBACK_ENDPOINT is set AND either --send is passed or SUBSTACK_FEEDBACK_AUTO_SEND=true. Default behavior is local-only.

Write what surprised you, not a bug report. Short, specific, one line: that is the part that compounds.

Output Delivery

Every command accepts --deliver <sink>. The output goes to the named sink in addition to (or instead of) stdout, so agents can route command results without hand-piping. Three sinks are supported:

Unknown schemes are refused with a structured error naming the supported set. Webhook failures return non-zero and log the URL + HTTP status on stderr.

Named Profiles

A profile is a saved set of flag values, reused across invocations. Use it when a scheduled agent calls the same command every run with the same configuration - HeyGen's "Beacon" pattern.

substack-pp-cli profile save briefing --json
substack-pp-cli --profile briefing categories list
substack-pp-cli profile list --json
substack-pp-cli profile show briefing
substack-pp-cli profile delete briefing --yes

Explicit flags always win over profile values; profile values win over defaults. agent-context lists all available profiles under available_profiles so introspecting agents discover them at runtime.

Exit Codes

Argument Parsing

Parse $ARGUMENTS:

1. Empty, help, or --help → show substack-pp-cli --help output
2. Starts with install → ends with mcp → MCP installation; otherwise → see Prerequisites above
3. Anything else → Direct Use (execute as CLI command with --agent)

MCP Server Installation

1. Install the MCP server:

   go install github.com/mvanhorn/printing-press-library/library/media-and-entertainment/substack/cmd/substack-pp-mcp@latest
   

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2. Register with Claude Code:

   claude mcp add substack-pp-mcp -- substack-pp-mcp
   

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3. Verify: claude mcp list

Direct Use

1. Check if installed: which substack-pp-cli If not found, offer to install (see Prerequisites at the top of this skill).
2. Match the user query to the best command from the Unique Capabilities and Command Reference above.
3. Execute with the --agent flag:

   substack-pp-cli <command> [subcommand] [args] --agent
   

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4. If ambiguous, drill into subcommand help: substack-pp-cli <command> --help.