cargo-mailbox-management

Sends email from inboxes Cargo provisions: sets up mailboxes on a sending domain, warms them up and ramps sends from 5 to 40 a day, sends with the sendEmail action, and reads replies, delivery events and unsubscribes. 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-project.

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.

bash

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. Everything on this page is live in the pinned CLI (1.0.66), including mailbox get-warmup-stats and the --daily-target default of 40 — both of which were merged-but-unpublished when this skill was written. On an older CLI, --daily-target reads "provider default if omitted" and get-warmup-stats silently prints the mailbox group help instead of erroring, so a missing subcommand here looks like a usage mistake rather than a stale install. cargo-ai mailboxManagement mailbox --help lists what your CLI actually has; re-run the session refresh in ../cargo/SKILL.md to catch up.

Bootstrap

Already signed in (cargo-ai whoami returns a workspace)? Skip to the next section.

bash

npm install -g @cargo-ai/cli            # no global install? prefix every command with `npx @cargo-ai/cli`
cargo-ai login --email [e-mail]  # 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 list is 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-allowance reports 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 in acceptable-use.md §2 — not a configuration question.
• Unsubscribes are automatic and absolute. Every send carries a signed List-Unsubscribe header; a recipient using it writes a workspace-wide suppression row, 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, rampLimit, 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 project with defineDomain and read it back from cargo.state.json. Say this to the user rather than guessing a UUID.

Pricing a domain before buying it has the same gap, and one direct API call closes it: GET /v1/domainManagement/domains/search?name=<domain> returns available and priceCredits (where null means not purchasable, not free). The domain side of a fleet — that call, sizing domains by blast radius rather than capacity, the apex redirect, DMARC, naming, and what dnsRecords owns once declared — is references/sending-domains.md.

bash

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, or private. outlook is accepted by the flag and always fails with transportNotSupported: the Graph transport has not shipped, so an Outlook mailbox cannot deliver. Pick one of the other three.
• --username — the local part only (jane for [e-mail]). 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 kind mailbox, from cargo-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 mailboxNotActive, which does not retry.

bash

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, error, comma-separated with no spaces. An inactive mailbox was disabled by the provider; errorCode says why (401 auth, 402 spam) and it will not send until it is fixed. An error mailbox is one Cargo cannot log into although the provider still calls it active (errorCode: "authenticationFailed"); it is retried hourly and goes back to active on the first login that works.
• none is the sentinel for "clear it" on --folder-uuid and --signature. On list, --folder-uuid none means "mailboxes in no folder".
• remove is 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. Warm-up starts on its own (target 40) the first time a mailbox goes pending → active; start-warmup is the retry after a failed enrolment or after stop-warmup, and on a mailbox already warming it returns warmupAlreadyStarted.

bash

cargo-ai mailboxManagement mailbox start-warmup <uuid> --daily-target 40
cargo-ai mailboxManagement mailbox get-warmup-stats <uuid>

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.
• --status on update-warmup accepts the whole enum, but only active and paused do anything: pending and failed are states the provider reaches on its own, and disabled is what stop-warmup is for.
• stop-warmup resets 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

bash

cargo-ai mailboxManagement mailbox get-send-allowance <uuid>
# → {"allowance":{"dailyLimit":12,"rampLimit":12,"sentCount":4,"remainingCount":8}}

Read remainingCount before enrolling a batch. Sends past it do not fail: they wait for the rolling 24h window to free a slot, so a backlog drains over the following days. A workflow run lives at most about 15 days, so a backlog deeper than ~15 days of allowance (about 600 sends on a warmed mailbox) outlives the run waiting for it. rampLimit is where the ramp stands before any dailySendLimit override tightens it.

Read what happened

bash

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 lastEmail and lastEvent are 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.
• --statuses on message list / thread list is the list status — pending, error, or an event kind. success is not in that set: a delivered message reads as sent or later.
• --kinds, --statuses, --reasons are all comma-separated with no spaces.
• bounced never 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, and event lists default to --limit 50 (max 200) and return a count. mailbox list and suppression list have no default limit (max 1000), and mailbox list returns no count — see references/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.

bash

cargo-ai mailboxManagement suppression list --reasons unsubscribed,manual
cargo-ai mailboxManagement suppression create --email [e-mail]

• Reasons are unsubscribed (the recipient's own choice, via List-Unsubscribe), bounced, complained, and manual. suppression create always records manual.
• 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

bash

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:

bash

cargo-ai orchestration action execute \
  --action '{"kind":"native","actionSlug":"sendEmail"}' \
  --data '{"mailboxUuid":"<mailbox-uuid>","to":"[e-mail]","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, and references.
• To keep a reply threaded, send the whole chain. references is every Message-ID in the thread so far, oldest first — not just the parent. Mail clients break the thread otherwise.
• The action is rate-limited per mailbox: capped at that mailbox's own daily limit, with a random 1 to 3 minute gap between two sends. A burst of 100 on a mailbox with 40 left sends 40 and the other 60 wait for the window to roll rather than failing.
• A refused send is a node error, not a thrown exception. recipientSuppressed, mailboxNotActive, mailboxSendingPaused, mailboxNotFound, and transportNotSupported need a human and do not retry; dailyLimitReached, credentialsMissing, and deliveryFailed retry on their own.
• There is no dry run from the CLI. The engine has one, but no action execute flag 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.

Reading events back from a workflow: listEmailEvents

mailboxManagement event list is the CLI read, but inside a workflow the delivery events on a thread come from a native action (CLI ≥ 1.0.86), so a play can branch on whether someone replied:

bash

cargo-ai orchestration action execute \
  --action '{"kind":"native","actionSlug":"listEmailEvents"}' \
  --data '{"threadUuid":"<thread-uuid>","kinds":["replied","clicked"],"limit":50}' \
  --wait-until-finished

• threadUuid is required; kinds is optional (omit for every event on the thread) and limit defaults to 50, capped at 200, newest first.
• Event kinds are sent, opened, clicked, replied, bounced, unsubscribed. Note the wire value is opened even though the UI labels it "Viewed".
• Each event returns uuid, mailboxUuid, messageUuid, threadUuid, kind, occurredAt, actorEmail, plus nullable url (on clicked), inboundRfcMessageId, and snippet.
• bounced still has no producer — nothing parses delivery-status notifications yet, so filtering on it returns nothing and proves nothing. Never report an empty bounce count as a clean list.

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 remove is the only way to stop it; there is no pause. Quote the fleet size and the monthly credit estimate from a live pricing get, and get an explicit yes, before the first create.
• 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 sendEmail re-bills on every run — and re-contacts the same people on every run, which is the §6 cadence gate in acceptable-use.md as much as a spend gate. Check get-send-allowance before enrolling a batch: rows past the allowance wait for later windows, and a backlog deeper than ~15 days of allowance outlives its run.
• The full spend rules — sampling before a full enrollment, the approval message, the receipt — are ../cargo-gtm/references/cost-discipline.md.

Declarative alternative: defineMailbox (project)

For the inbox itself, prefer a project — 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-project/SKILL.md and "Declarative vs imperative" in ../cargo/SKILL.md.

Use this skill's imperative commands for one-off provisioning, and for everything a project 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.

bash

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.