Substack

substack — read & publish on Substack via your own cookies

Drives the user's real Substack account through the same internal web API the site uses (Substack has no official public write API), authenticated by the login cookie they captured with the ACE extension. No browser, no third-party deps — just urllib. The publish flow mirrors the community python-substack library: create draft → prepublish → publish.

The connector injects the cookie jar as an env var:

• SUBSTACK_COOKIES — a JSON array of cookies (substack.sid, substack.lli, …). Secret — never echo or print it. Substack authenticates writes with the session cookie alone (no CSRF token header needed).

CLI

The skill ships scripts/substack.py — self-contained, stdlib only.

# $SKILL_DIR can point at another skill loaded this turn — anchor on our own
# script, and re-run this at the top of every Bash block (fresh shell each time).
SUB="$SKILL_DIR/scripts/substack.py"; [ -f "$SUB" ] || SUB=$(find /tmp -maxdepth 8 -path '*/skills/*/scripts/substack.py' 2>/dev/null | head -1)
[ -f "$SUB" ] || { echo "substack script not found (SKILL_DIR=$SKILL_DIR)" >&2; exit 1; }
python3 "$SUB" whoami                     # who is logged in + primary publication
python3 "$SUB" articles --limit 20        # my published posts + stats

Verify the connection first

SUB="$SKILL_DIR/scripts/substack.py"; [ -f "$SUB" ] || SUB=$(find /tmp -maxdepth 8 -path '*/skills/*/scripts/substack.py' 2>/dev/null | head -1)
python3 "$SUB" whoami
# → {"user_id": ..., "name": "...", "handle": "...", "publication": "...", "publication_url": "https://<sub>.substack.com"}

On an auth error the cookie is expired — have the user reconnect at https://auth.acedata.cloud/user/connections. Do not loop-retry.

Publishing — GATED (dry-run unless trailing --confirm)

publish writes to the user's real account. Content is Markdown, converted to Substack's ProseMirror blocks: #..######→heading, ```→code block, >→blockquote, -/*/1.→lists, ---→horizontal rule, everything else →paragraphs. Inline bold, italic, code, strike, and [links](url) render as real Substack formatting; bare https://… URLs are auto-linked.

Without a trailing --confirm it dry-runs. --confirm is honored only as the last argument. Always show the dry-run, get an explicit "yes", then re-run.

SUB="$SKILL_DIR/scripts/substack.py"; [ -f "$SUB" ] || SUB=$(find /tmp -maxdepth 8 -path '*/skills/*/scripts/substack.py' 2>/dev/null | head -1)
# dry-run (shows the plan, writes nothing)
python3 "$SUB" publish --title "Title" --content-file post.md

# private draft (visible only in the user's dashboard)
python3 "$SUB" publish --title "Title" --content-file post.md --draft-only --confirm

# go LIVE on the web (does NOT email subscribers)
python3 "$SUB" publish --title "Title" --content-file post.md --confirm

# go LIVE and email subscribers (use only when the user explicitly asks)
python3 "$SUB" publish --title "Title" --content-file post.md --send-email --confirm

• --draft-only stops at a draft — default to this unless the user asked to go live. Returns an edit_url to review in the Substack editor.
• Publishing does NOT email subscribers unless --send-email is passed. Emailing a newsletter is irreversible and hits every subscriber's inbox — never add --send-email without an explicit request.
• --subtitle sets the post subtitle; --audience is one of everyone (default, free/public), only_paid, founding, only_free.

Gotchas

• This is the user's real Substack account. Confirm before any publish, and keep --draft-only as the safe default.
• --send-email blasts the whole subscriber list and cannot be undone — opt in only on explicit request.
• Substack sits behind Cloudflare; an occasional 403/429 on a read is transient — the CLI auto-retries reads once. A persistent 401/403 means the cookie is genuinely expired (reconnect); the CLI never retries a write.
• Never print SUBSTACK_COOKIES — it is full account access.
• ToS: acts only on the user's own account with their own captured cookie.

Record the output

After you successfully publish and obtain the live result URL, call the built-in publish_artifact tool ONCE so the user can track this deliverable in My Outputs:

publish_artifact(kind="article", channel="substack", title="<title>", url="<the REAL returned URL>", status="delivered")

Use the real returned URL — never fabricate one. Call it once per published item, only after delivery is confirmed; skip it (or use status="failed") if publishing failed. See _shared/artifacts.md.