cargo-mailbox-management
Send mail from inboxes Cargo owns — provision mailboxes on a sending domain, run provider warm-up and the 5→40/day send ramp, deliver with the `sendEmail` action, and read back threads, replies, delivery events, and the workspace suppression list. Triggers: "set up a sending mailbox", "provision inboxes for outbound", "warm up this mailbox", "how many sends do I have left today", "send this from Cargo", "did they reply", "who unsubscribed", "suppress this recipient", "take me off your list", "never email them again", "what do mailboxes cost", "my mailbox is stuck pending". A mailbox is a recurring monthly credit charge, and every send is gated on basis, suppression, and relevance. Skip when: writing the copy or building the audience — use cargo-gtm; the mailbox belongs in git — use cargo-cdk.
How do I install this agent skill?
npx skills add https://github.com/getcargohq/cargo-skills --skill cargo-mailbox-managementIs this agent skill safe to install?
- Gen Agent Trust Hubpass
The skill provides comprehensive instructions for managing email mailboxes using the cargo-ai CLI, including provisioning, warming up, and sending emails. It has a minor security surface related to processing incoming email content which may contain instructions from external parties.
- Socketpass
No alerts
- Snykwarn
Risk: MEDIUM · 1 issue
What does this agent skill do?
Cargo CLI — Mailbox Management
Mailboxes. A mailbox is a real sending inbox the workspace owns — provisioned through
Cargo on a sending domain the workspace also owns, with SMTP and IMAP credentials Cargo holds
and uses to deliver outbound mail and to read the replies that come back. Two things follow,
and both are easy to get wrong: a mailbox is a recurring monthly credit charge rather than
a per-record one, and this domain does not send. It provisions the inbox, ramps it, and
reports on what it did; the send itself is the sendEmail action, under
cargo-orchestration.
cargo-ai mailboxManagement mailbox … # provision, warm-up, send allowance
cargo-ai mailboxManagement message … # outbound sends
cargo-ai mailboxManagement thread … # conversations, and the replies on them
cargo-ai mailboxManagement event … # sent / opened / clicked / replied / unsubscribed
cargo-ai mailboxManagement suppression … # workspace-wide do-not-send list
cargo-ai mailboxManagement pricing … # monthly credits per mailbox flavour
Version note.
mailbox get-warmup-statsand the documented--daily-targetdefault of 40 are merged but not yet on npm. On an older CLI,--daily-targetreads "provider default if omitted", andget-warmup-statssilently prints themailboxgroup help instead of erroring — so an unrecognised subcommand here looks like a usage mistake, not a missing feature.cargo-ai mailboxManagement mailbox --helplists what your CLI actually has. Everything else on this page is live in the released CLI; re-run the session refresh in../cargo/SKILL.mdto pick up the rest.
Bootstrap
Already signed in (cargo-ai whoami returns a workspace)? Skip to the next section.
npm install -g @cargo-ai/cli # no global install? prefix every command with `npx @cargo-ai/cli`
cargo-ai login --email you@company.com # emailed code, no browser; creates the account on first use
# alternatives: --oauth (browser) · --token <api-token> (CI)
cargo-ai whoami # confirm the active workspace before any write
Every command prints JSON to stdout; failures exit non-zero with {"errorMessage": "..."}.
Nothing in this domain is asynchronous — every command is a single HTTP call, so there is no
run to poll (the one thing that looks async, a freshly created mailbox sitting at pending,
is polled with mailbox refresh-status, not with run get). Mailboxes are guarded by
mailboxManagement:read / mailboxManagement:write permissions, which an admin and an editor
both hold and a viewer does not; if a create or update returns a permission error, the token is
read-only (../cargo-workspace-management/SKILL.md).
When the full skill bundle is installed, ../cargo/references/prerequisites.md
adds the CLI version pin, token scopes, and the admin-only surface.
Before any send — three checks
This is a blocking gate, not advice. Cargo owning the mailbox changes who presses send; it
changes nothing about whether the message should be sent. The canonical rules are
../cargo-gtm/references/acceptable-use.md §3 and
they apply here unchanged — run all three before the first sendEmail, not after:
- Basis — which permission covers this audience (customers, opted-in contacts, event attendees, or a documented legitimate-interest case for a B2B role)?
- Suppression — subtract the workspace suppression list from the audience before you
enrich or send.
suppression listis free and this domain is the source of truth for it. - Relevance — can you name, per recipient, why this message is for them?
Any check that fails is a stop-and-ask. Two obligations are specific to Cargo-owned sending:
- The ramp is a ceiling, not a target.
get-send-allowancereports what a mailbox may send today; it is not a quota to fill. Asking to raise it, to spread one campaign across a fleet of fresh mailboxes to clear the same volume, or to rotate identities so filters see less from each, is the evasion refusal inacceptable-use.md§2 — not a configuration question. - Unsubscribes are automatic and absolute. Every send carries a signed
List-Unsubscribeheader; a recipient using it writes a workspace-widesuppressionrow, and the next send to that address is refused by the engine. There is no removal command, and that is the point — never route around a suppression to re-contact someone.
The two numbers that govern a mailbox
They look similar and mean opposite things. Confusing them is the most common way to mis-read a mailbox's health.
mailbox get-send-allowance | mailbox get-warmup-stats | |
|---|---|---|
| Measures | Your real outreach | The provider's dummy warm-up traffic |
| Window | Rolling 24 hours | Today, UTC |
| Returns | dailyLimit, sentCount, remainingCount | sentCount, deliveredCount, spamCount, inboxRate, spamRate |
| Answers | "How many more may I send?" | "Is this inbox landing in the inbox or in spam?" |
dailyLimit is not a setting — it is derived from how long warm-up has been running. The
arithmetic, the warmupStatus transitions, and how to size a fleet against it are in
references/warmup-and-allowance.md. Read it before
you promise anyone a send volume.
Commands
All commands output JSON. Reads need mailboxManagement:read; everything that provisions,
updates, deletes, or suppresses needs mailboxManagement:write.
Provision a mailbox
First, the gap you will hit. mailbox create requires --domain-uuid, and there is no
cargo-ai command that lists sending domains — the domainManagement API exists but has no
CLI surface yet. Get the UUID from the Cargo web app, or declare the domain in a CDK repo with
defineDomain and read it back from cargo.state.json. Say this to the user rather than
guessing a UUID.
cargo-ai mailboxManagement mailbox create \
--domain-uuid <domain-uuid> \
--type google \
--username jane \
--first-name Jane \
--last-name Doe \
--signature '<p>Jane Doe · Acme</p>' \
--folder-uuid <folder-uuid>
cargo-ai mailboxManagement mailbox refresh-status <uuid> # repeat until status is "active"
--type—google,shared, orprivate.outlookis accepted by the flag and always fails withtransportNotSupported: the Graph transport has not shipped, so an Outlook mailbox cannot deliver. Pick one of the other three.--username— the local part only (janeforjane@acme.com). Lowercased; letters, digits, dots, dashes and underscores, 1–64 characters, starting and ending alphanumeric.--first-name/--last-name— the From header the recipient sees. Use a real person's name under a real identity; a fabricated sender is a §2 refusal.--signature— HTML, stored on the mailbox (max 10,000 characters).--folder-uuid— a folder of kindmailbox, fromcargo-workspace-management.
create returns immediately with status: "pending" — the provider has not issued credentials
yet. It reaches active when refresh-status says so, or on its own within five minutes; a
send attempted before then fails with credentialsMissing.
cargo-ai mailboxManagement mailbox list # every mailbox
cargo-ai mailboxManagement mailbox list --statuses active # comma-separated, no spaces
cargo-ai mailboxManagement mailbox list --domain-uuid <uuid>
cargo-ai mailboxManagement mailbox get <uuid>
cargo-ai mailboxManagement mailbox update --uuid <uuid> --first-name Janet
cargo-ai mailboxManagement mailbox update --uuid <uuid> --folder-uuid none # "none" clears
cargo-ai mailboxManagement mailbox remove <uuid> # deletes at the provider too
--statuses—pending,active,inactive, comma-separated with no spaces. Aninactivemailbox was disabled by the provider;errorCodesays why (401auth,402spam) and it will not send until it is fixed.noneis the sentinel for "clear it" on--folder-uuidand--signature. Onlist,--folder-uuid nonemeans "mailboxes in no folder".removeis how monthly billing stops. There is no pause.
Warm it up
A mailbox that never starts warm-up is pinned at 5 real sends a day, forever. Warm-up is what moves it, and it takes 45 days to finish.
cargo-ai mailboxManagement mailbox start-warmup <uuid> --daily-target 40
cargo-ai mailboxManagement mailbox get-warmup-stats <uuid> # next CLI release
cargo-ai mailboxManagement mailbox update-warmup --uuid <uuid> --status paused
cargo-ai mailboxManagement mailbox update-warmup --uuid <uuid> --daily-target 25
cargo-ai mailboxManagement mailbox stop-warmup <uuid> # resets the ramp
--daily-target— warm-up messages per day at full ramp, 1–40 (default 40). This is the provider's dummy traffic, not your send allowance.--statusonupdate-warmupaccepts the whole enum, but onlyactiveandpauseddo anything:pendingandfailedare states the provider reaches on its own, anddisabledis whatstop-warmupis for.stop-warmupresets the Cargo send ramp as well as tearing down provider warm-up — the mailbox drops back to 5/day and starts the 45 days over. Pause instead unless you mean it.
Check the allowance before you send
cargo-ai mailboxManagement mailbox get-send-allowance <uuid>
# → {"allowance":{"dailyLimit":12,"sentCount":4,"remainingCount":8}}
Read remainingCount before enrolling a batch. Sends past it do not queue for tomorrow — they
fail immediately with dailyLimitReached, one wasted run per row.
Read what happened
cargo-ai mailboxManagement message list --mailbox-uuid <uuid> --statuses sent,replied --limit 50
cargo-ai mailboxManagement message get <uuid>
cargo-ai mailboxManagement thread list --mailbox-uuid <uuid> --search acme
cargo-ai mailboxManagement thread get <uuid>
cargo-ai mailboxManagement event list --kinds replied,unsubscribed --occurred-after 2026-08-01
- Message vs thread vs event. A message is one outbound send. A thread is a
conversation — its
lastEmailandlastEventare what you sort a reply queue on. An event is something that happened to a message (sent,opened,clicked,replied,bounced,unsubscribed). Inbound replies are events, not message rows; only outbound mail is a message. --statusesonmessage list/thread listis the list status —pending,error, or an event kind.successis not in that set: a delivered message reads assentor later.--kinds,--statuses,--reasonsare all comma-separated with no spaces.bouncednever fires yet. Nothing parses delivery-status notifications, so bounces do not produce events and do not auto-suppress. Do not build a deliverability report that treats an empty bounce count as a clean list.message,thread, andeventlists default to--limit 50(max 200) and return acount.mailbox listandsuppression listhave no default limit (max 1000), andmailbox listreturns nocount— seereferences/response-shapes.md.
Suppression
Workspace-wide, not per mailbox: a recipient opting out is opting out of the sender, not of one address the sender happens to own.
cargo-ai mailboxManagement suppression list --reasons unsubscribed,manual
cargo-ai mailboxManagement suppression create --email opted-out@acme.com
- Reasons are
unsubscribed(the recipient's own choice, viaList-Unsubscribe),bounced,complained, andmanual.suppression createalways recordsmanual. - It is idempotent — suppressing an already-suppressed address returns the existing row.
- Addresses are normalised (
trim().toLowerCase()) on both write and check, so casing and stray whitespace cannot slip a suppressed recipient back into a send. - There is no
suppression remove. That is deliberate.
Pricing
cargo-ai mailboxManagement pricing get
# → {"monthlyCredits":{"google":125,"outlook":160,"shared":100,"private":100}}
Read this live before quoting a fleet cost — the figures above are what the workspace returned at the time of writing, not a constant.
Sending: the sendEmail action
Delivery is deliberately not in this CLI domain. It is a native orchestration action so that sends inherit orchestration's pacing, retry, and credit machinery:
cargo-ai orchestration action execute \
--action '{"kind":"native","actionSlug":"sendEmail"}' \
--data '{"mailboxUuid":"<mailbox-uuid>","to":"jane@acme.com","subject":"...","bodyHtml":"<p>…</p>"}' \
--wait-until-finished
- 0.1 credits per send, fixed. The action carries no
config; the inputs go in--data, like every other action (../cargo-orchestration/SKILL.md). - Optional
bodyText(generated from the HTML when omitted),inReplyTo, andreferences. - To keep a reply threaded, send the whole chain.
referencesis everyMessage-IDin the thread so far, oldest first — not just the parent. Mail clients break the thread otherwise. - The action is rate-limited per mailbox to that mailbox's own daily limit, spread across the day. A burst of 100 on a mailbox with 40 left fails the 41st immediately rather than parking it for a day.
- A refused send is a node error, not a thrown exception.
recipientSuppressed,mailboxNotActive, andtransportNotSupportedneed a human and do not retry;dailyLimitReached,credentialsMissing, anddeliveryFailedretry on their own. - There is no dry run from the CLI. The engine has one, but no
action executeflag reaches it — the send is live the moment you run the command. Send to yourself first.
Threading, the full refusal table, and what Cargo injects into every message (unsubscribe
header, open pixel, click redirect) are in references/sending.md.
Cost discipline
This domain bills differently from the rest of the pack, and the difference is the thing to say out loud before provisioning anything.
- A mailbox is a monthly, recurring charge — 100–160 credits per mailbox, per month, for
as long as it exists. Five mailboxes is 500–625 credits every month, not once.
mailbox removeis the only way to stop it; there is no pause. Quote the fleet size and the monthly credit estimate from a livepricing get, and get an explicit yes, before the firstcreate. - Sends are 0.1 each, so volume is cheap and the fleet is not. Do the arithmetic in that order.
- A play or scheduled tool that calls
sendEmailre-bills on every run — and re-contacts the same people on every run, which is the §6 cadence gate inacceptable-use.mdas much as a spend gate. Checkget-send-allowancebefore enrolling a batch: rows past the allowance burn a run each and deliver nothing. - The full spend rules — sampling before a full enrollment, the approval message, the receipt —
are
../cargo-gtm/references/cost-discipline.md.
Declarative alternative: defineMailbox (CDK)
For the inbox itself, prefer CDK — the mailbox create help says so, and the reason is that
a mailbox is long-lived infrastructure with a monthly cost, which is exactly what belongs in
git and in a plan you can review. defineMailbox (with defineDomain for the sending domain)
covers it; adopt: true binds a mailbox bought in the web app instead of provisioning a second
one. See ../cargo-cdk/SKILL.md and "Declarative vs imperative" in
../cargo/SKILL.md.
Use this skill's imperative commands for one-off provisioning, and for everything CDK does not model at all: warm-up, allowance, messages, threads, events, and suppressions.
When the CLI surprises you
If a documented flag or response shape doesn't match what you observe, re-refresh the CLI and
skills; if it still doesn't add up, file a report — it's read by the team. The missing
domainManagement surface is a live example: mailbox create needs a --domain-uuid that no
command can produce.
cargo-ai workspaceManagement report create \
--title "<one-line summary>" \
--description "<exact command(s), errorMessage verbatim, expected vs actual, UUIDs>"
Presenting results
Follow ../cargo/references/interaction.md: lead with the
outcome ("mailbox active, 8 of today's 12 sends left, 2 replies since Monday"), summarize a
fleet or a reply queue as a compact table, and never dump raw mailbox get or event list JSON
into the conversation. When you report a fleet, report its monthly cost, not a one-off one.
How can the creator link this skill?
Add the canonical catalog link to the repository README so users can inspect current installs and available audits. The publishing guide covers the complete discovery path.
<a href="https://skillzs.dev/skills/getcargohq/cargo-skills/cargo-mailbox-management">View cargo-mailbox-management on skillZs</a>