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Sendmux Agent Skills teach AI coding tools how to send email, read mailboxes, manage team resources, and choose low-token Sendmux calls. Use them when your agent needs Sendmux context before it writes commands, API calls, or integration code.
Skills do not grant Sendmux access by themselves. Create API keys, authorise MCP, or use agent access first, then let the skill choose the right surface for the task. If you use agent access, immediately save the returned claim_token and agent credential bundle before token exchange: mailbox metadata, token endpoints, resource URLs, and identity_assertion. Keep the identity_assertion or pre-claim token until the owner invite returns 202.

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Install from a marketplace

Use the marketplace path when your AI tool supports plugins. It installs the full Sendmux pack and keeps marketplace updates separate from your project files.
  1. Open Customize.
  2. Go to Plugins.
  3. In Personal plugins, click + and choose Add marketplace.
  4. Choose Add from a repository.
  5. Enter Sendmux/skills, then install the Sendmux plugin.
Add the marketplace first.
Then open Plugins in the Codex app or /plugins in Codex CLI and install Sendmux from the Sendmux marketplace.

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Install with Agent Skills

Use skills add when your agent supports raw Agent Skills rather than plugin marketplaces.
Install one skill when you only need a focused workflow.
Update installed skills later.

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Supported targets

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What the pack teaches

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Choose the right surface

Use send-capable smx_mbx_ keys or owner-approved Sending-resource smx_agent_ tokens for Sending work. Use smx_mbx_ keys or scoped smx_agent_ tokens for allowed Mailbox work. Use team-scoped smx_root_ keys for Management work. Pre-claim smx_agent_ tokens do not include email.send. When an agent has no Sendmux credential, start with agent access: request a registration challenge, solve it, register the mailbox at the identity_endpoint with proof_of_work, immediately save the returned claim_token and full agent credential bundle in a secure store such as 1Password, an OS keychain, or the agent platform’s encrypted secret store before token exchange, exchange the identity assertion, then invite the human owner with the pre-claim access token. The claim token is required later for owner-approved sending and cannot create the owner invite. If the agent loses both the identity assertion and pre-claim token before the invite returns 202, register again and invite immediately. If any agent-auth endpoint returns 429, use Retry-After or retry_after before retrying.

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Next steps

MCP

Connect hosted or local Sendmux MCP tools.

Agent access

Let an agent register a constrained mailbox and invite its owner.

CLI

Run Sendmux workflows from your terminal.

SDKs

Choose an SDK package for application code.

API keys

Create scoped credentials for tools and agents.