Sendmux Agent Skills
Official Sendmux skills for AI coding agents.
Marketplace install
This repository contains Sendmux plugin bundles for Cursor, Claude, and Codex. The Cursor bundle is prepared but is not available through /add-plugin until its marketplace submission is approved.
Cursor (after marketplace publication):
/add-plugin sendmux
Claude app, Claude Desktop, and Cowork:
- Open Customize.
- Go to Plugins.
- In Personal plugins, click + and choose Add marketplace.
- Choose Add from a repository.
- Enter
Sendmux/skills, then install the Sendmux plugin.
Claude Code:
/plugin marketplace add Sendmux/skills
/plugin install sendmux@sendmux
/reload-plugins
Codex app and Codex CLI:
codex plugin marketplace add Sendmux/skills
Then open Plugins in the Codex app or /plugins in Codex CLI and install Sendmux from the Sendmux marketplace.
Direct Agent Skills install
Use skills add when your agent supports raw Agent Skills rather than plugin marketplaces.
npx skills add Sendmux/skills
Install one skill from the pack:
npx skills add Sendmux/skills --skill sendmux-send-email
Update an installed pack:
npx skills update
What This Pack Teaches
- Choose the cheapest correct Sendmux surface for the task: MCP for connected agents, the
sendmuxCLI for terminal one-shots, and SDKs for application flows. - Use the right credential for each job:
smx_root_*for account-level work, send-capablesmx_mbx_*keys or owner-approved Sending-resourcesmx_agent_*tokens for sending,smx_mbx_*keys for single-mailbox work, and scopedsmx_agent_*tokens for self-registered agent mailbox work. - Prefer efficient calls: batch operations, cursor pagination, conditional requests, idempotency keys, counts, snippets, and delta sync where the public surface supports them.
- Verify results before reporting success.
Skills Catalogue
The catalogue is built item by item from the local API, SDK, CLI, and MCP source of truth.
| Skill | Use when |
|---|---|
sendmux-getting-started | Choosing a Sendmux surface, setting up auth, or making a first verified call. |
sendmux-send-email | Sending single or batch transactional email. |
sendmux-attachments | Uploading, downloading, or sending attachments without wasting context on base64. |
sendmux-mailbox-agent | Reading, triaging, replying, or syncing one mailbox. |
sendmux-management | Managing domains, mailboxes, sending accounts, webhooks, billing, and logs. |
sendmux-cli | Using the sendmux CLI from a terminal. |
sendmux-mcp-setup | Connecting Sendmux MCP servers to an agent client. |
sendmux-token-efficient-usage | Choosing low-token Sendmux calls and avoiding wasteful reads. |
sendmux-email-for-agents | Giving an AI agent an inbox, challenge-first self-registration flow, or email workflow, even when Sendmux is not named. |
Target matrix
| Target | Recommended install |
|---|---|
| Cursor | After official marketplace publication, run /add-plugin sendmux. |
| Claude app, Claude Desktop, Cowork | Add marketplace from repository Sendmux/skills, then install Sendmux. |
| Claude Code | /plugin marketplace add Sendmux/skills, then /plugin install sendmux@sendmux. |
| Codex app and Codex CLI | codex plugin marketplace add Sendmux/skills, then install Sendmux from Plugins or /plugins. |
| Agent Skills clients | npx skills add Sendmux/skills. |
| Single-skill installs | npx skills add Sendmux/skills --skill <skill-name>. |
Marketplace plugins and raw Agent Skills only teach workflows. They do not grant Sendmux access. Authorise hosted MCP, create API keys, or use agent access before asking an agent to act on Sendmux data.
Development
This repo uses the Agent Skills format:
skills/
<skill-name>/
SKILL.md
references/
scripts/
assets/
Each skill must be validated, benchmarked against a baseline, and packaged before it is marked complete.
Generate Cursor, Claude, and Codex marketplace bundles:
node scripts/build-plugin-bundles.mjs
node scripts/check-plugin-bundles.mjs
The canonical skill source stays in skills/. Cursor reads it directly; generated Cursor, Claude, and Codex manifests plus both MCP files are checked for drift in CI.
See docs/eval-lint-package-playbook.md for the local eval, lint, package, and install-smoke loop.
See docs/regen-update-playbook.md for the source drift check and regeneration procedure.