Send one or many emails through Sendmux using approved mailbox or agent credentials, idempotency keys, attachments, MCP, CLI, SDKs, or HTTP.
Coding
sendmux-cli
Try itUse the Sendmux CLI for durable agent inbox registration, owner invites, profiles, and terminal-driven Management, Mailbox, and Sending workflows.
What it does
Use the Sendmux CLI for durable agent inbox registration, owner invites, profiles, and terminal-driven Management, Mailbox, and Sending workflows.
The skill document
Sendmux CLI
ClawHub account note
This ClawHub skill connects OpenClaw agents to Sendmux. Some workflows require a Sendmux account and an appropriate Sendmux API key or agent token. Sendmux account usage is external to ClawHub; do not ask users to paste secrets into chat.
Use this skill when the terminal is the right Sendmux surface.
Boundaries
- Do not ask the user to paste API keys.
- Use
smx_root_keys only formanagement:*commands. - Use
smx_mbx_keys or scopedsmx_agent_tokens formailbox:*commands. - Use a send-capable
smx_mbx_key or owner-approved Sending-resourcesmx_agent_token forsending:*commands. Pre-claimsmx_agent_tokens cannot send. - Do not run destructive commands without explicit confirmation.
- Use
--jsonfor agent-readable output. - Prefer task-specific Sendmux skills when the user needs strategy; use this skill for exact CLI mechanics.
Install
npm install -g @sendmux/cli
sendmux --help
The package exposes the sendmux binary.
Use the latest CLI before using smx_agent_ tokens; older installs may reject that prefix before sending a request.
Profiles
Create separate profiles for root and mailbox keys.
sendmux profiles:set default --api-key "$SENDMUX_ROOT_KEY" --default --json
sendmux profiles:set mailbox --api-key "$SENDMUX_MBX_KEY" --json
sendmux profiles:set sending --api-key "$SENDMUX_MBX_KEY" --json
sendmux profiles:list --json
sendmux profiles:show default --json
Profile reads mask stored keys. profiles:set reports key_kind as root or mailbox.
Authentication resolution:
--api-key, thenSENDMUX_API_KEY.- If no direct key is present,
--profile/-p, thenSENDMUX_PROFILE, then the configured default profile. - Base URL comes from
--base-url, thenSENDMUX_BASE_URL, then the selected profile.
Preflight
The CLI infers key kind from the prefix before sending a request.
| Command surface | Required key |
|---|---|
management:* | smx_root_ |
mailbox:* | smx_mbx_ or scoped smx_agent_ |
sending:* | Send-capable smx_mbx_ key or owner-approved Sending-resource smx_agent_ token |
Wrong-key examples fail before network:
Command requires a root API key, but --api-key contains a mailbox API key.
Command requires a send-capable `smx_mbx_` key or owner-approved Sending-resource `smx_agent_` token, but --api-key contains a root API key.
Command catalogue
The CLI exposes generated operation commands:
| Surface | Count | Examples |
|---|---|---|
| Management | 53 | management:domains:list, management:create-domain, management:create-mailbox, management:get-spend-summary, management:create-webhook |
| Mailbox | 41 | mailbox:search-message-snippets, mailbox:batch-get-messages, mailbox:query-message-changes, mailbox:send-message, mailbox:list-granted-mailboxes |
| Sending | 7 | sending:get-open-api-spec, sending:send, sending:send:batch, sending:upload-attachment, sending:create-attachment-upload, sending:complete-attachment-upload, sending:get-attachment |
| Profiles | 3 | profiles:list, profiles:set, profiles:show |
Use command-level help to discover accepted path, query, header, and body fields:
sendmux management:create-domain --help
sendmux mailbox:search-message-snippets --help
sendmux sending:send:batch --help
sendmux sending:upload-attachment --help
Operation flags
Operation commands share these flags:
| Flag | Use |
|---|---|
--api-key | Direct key; overrides profile/env profile lookup. |
--base-url | Override API base URL. |
--profile, -p | Select a local profile. |
--body | Inline JSON request body, or text bytes for byte-oriented operations. |
--body-file | Read a JSON request body or byte payload from a file. |
--attach | Attach a local file to supported send commands. Repeat for multiple files. |
--file | Read a local file for mailbox attachment upload convenience commands. |
--via-presigned | Upload a mailbox --file through a short-lived signed URL instead of API bytes. |
--content-type | Override inferred MIME type for --attach or --file. |
--path name=value | Path parameters. Repeat for multiple path params. |
--query name=value | Query parameters. Repeat for filters and pagination. |
--header name=value | Headers accepted by the operation. Repeat for multiple headers. |
--idempotency-key | Shortcut for Idempotency-Key. Works only when the operation supports it. |
--if-match | Shortcut for If-Match. Works only when the operation supports it. |
--if-none-match | Shortcut for If-None-Match. Works only when the operation supports it. |
--json | Machine-readable output. |
--path, --query, and --header require name=value. Booleans use true or false. Repeat an array-valued parameter rather than comma-joining it.
Pass either --body or --body-file, not both.
Use sendmux-attachments for attachment-heavy flows and size/token trade-offs.
Examples
Create a domain:
sendmux management:create-domain \
--profile default \
--idempotency-key "$IDEMPOTENCY_KEY" \
--body '{"domain":"example.com","mode":"send_receive"}' \
--json
Get domain DNS records:
sendmux management:get-domain-zone-file \
--profile default \
--path public_id=mdom_abc \
--json
Search a mailbox without reading full messages:
sendmux mailbox:search-message-snippets \
--profile mailbox \
--query q=invoice \
--query is_unread=true \
--query limit=10 \
--json
Batch-read selected mailbox messages:
sendmux mailbox:batch-get-messages \
--profile mailbox \
--body '{
"ids": ["eml_abc", "eml_def"],
"body_mode": "clean_json",
"max_body_chars": 4000
}' \
--json
Send a batch:
sendmux sending:send:batch \
--profile sending \
--idempotency-key "$IDEMPOTENCY_KEY" \
--body-file ./messages.json \
--json
Send through the Sending API with a local attachment:
sendmux sending:send \
--profile sending \
--idempotency-key "$IDEMPOTENCY_KEY" \
--attach ./report.pdf \
--body '{"from":{"email":"sender@example.com"},"to":{"email":"user@example.com"},"subject":"Report","html_body":"Attached."}' \
--json
sending:send --attach uploads the file first and injects an attachment_id reference; it does not place base64 in the send body.
Upload a Sending attachment separately:
sendmux sending:upload-attachment \
--profile sending \
--body-file ./report.pdf \
--query filename=report.pdf \
--query content_type=application/pdf \
--json
Send a mailbox message with a local attachment:
sendmux mailbox:send-message \
--profile mailbox \
--idempotency-key "$IDEMPOTENCY_KEY" \
--attach ./report.pdf \
--body '{"to":[{"email":"user@example.com","name":null}],"subject":"Report","text_body":"Attached."}' \
--json
Mailbox attachment upload commands share the 7,500,000 byte per-attachment cap. For larger files, split the file or host it externally and send a link.
Upload a mailbox attachment by presigned URL:
sendmux mailbox:upload-attachment \
--profile mailbox \
--file ./report.pdf \
--via-presigned \
--json
Poll one unchanged-safe delivery log:
sendmux management:get-email-log \
--profile default \
--path public_id=dlog_abc \
--if-none-match "$ETAG" \
--json
Routing
- First setup/auth check:
sendmux-getting-started. - Sending strategy and body shape:
sendmux-send-email. - Attachment file paths and presigned upload/download:
sendmux-attachments. - Mailbox read, search, sync, triage, or reply:
sendmux-mailbox-agent. - Account-level management strategy:
sendmux-management. - MCP connection setup:
sendmux-mcp-setup. - Cheapest-call doctrine:
sendmux-token-efficient-usage.
Related skills
Manage Sendmux domains, mailboxes, mailbox keys, sending accounts, webhooks, logs, billing, and account-level setup.
Set up Sendmux for agents, register a durable inbox without an existing key, link an owner, choose a runtime surface, and make the first harmless call.
Give OpenClaw agents a Sendmux inbox to receive, triage, route, reply to, and send email with owner approval and scoped credentials.
Let an OpenClaw agent read, search, count, sync, triage, file, delete, thread, and reply from one Sendmux mailbox efficiently.
Choose low-token Sendmux calls across MCP, CLI, SDKs, and HTTP by using snippets, counts, batches, deltas, cursors, ETags, and idempotency.