Skill comparison
Compare agent skills before installing.
Comparing 4 skills
Use this as a shortlist, then open the skill detail page before adopting.
Decision summary
PHPMailer is the strongest overall pick here because it has a 100/100 readiness score and fits Workflow automation.
Strongest overall
PHPMailer
Use this as a leading candidate, then validate the README and install path in your own agent stack.
Fastest prototype
PHPMailer
Best first install candidate based on install readiness and adoption.
Freshest repo
Mailio
Most recent maintenance signal among this shortlist.
| Signal | Mailio mailio is a cross platform C++ library for MIME format and SMTP, POP3, IMAP protocols. It is based on the standard C++ 17 and Boost library. | PHPMailer The classic email sending library for PHP | Mailspring :love_letter: A beautiful, fast and fully open source mail client for Mac, Windows and Linux. | Mailinabox Mail-in-a-Box helps individuals take back control of their email by defining a one-click, easy-to-deploy SMTP+everything else server: a mail server in a box. |
|---|---|---|---|---|
| Quality | 73/100 Strong | 100/100 Excellent | 100/100 Excellent | 100/100 Excellent |
| Decision verdict | 72/100 Strong shortlist Shortlist this skill and compare it with close alternatives before production adoption. | 100/100 Production-ready Use this as a leading candidate, then validate the README and install path in your own agent stack. | 100/100 Production-ready Use this as a leading candidate, then validate the README and install path in your own agent stack. | 100/100 Production-ready Use this as a leading candidate, then validate the README and install path in your own agent stack. |
| Adoption | 477 stars Verified outcomes are shown on each skill page | 22K stars Verified outcomes are shown on each skill page | 18K stars Verified outcomes are shown on each skill page | 15K stars Verified outcomes are shown on each skill page |
| Freshness | Jun 15, 2026 | Jun 6, 2026 | Jun 15, 2026 | May 24, 2026 |
| Use-case fit | ||||
| Workflow fit | ||||
| Platform hints | C++, Email, Claude Code | PHP, Email, Claude Code | JavaScript, Email, Claude Code | Python, Email, Claude Code |
| Warnings | No OpenAgentSkill engagement data yet | No OpenAgentSkill engagement data yet | No OpenAgentSkill engagement data yet | No OpenAgentSkill engagement data yet |
| Best for | Workflow automation workflows · Claude Code teams · builders willing to evaluate younger projects | Workflow automation workflows · Claude Code teams · teams that value GitHub adoption signals | Workflow automation workflows · Claude Code teams · teams that value GitHub adoption signals | Workflow automation workflows · Claude Code teams · teams that value GitHub adoption signals |
| Not ideal for | teams that need a vendor-supported SLA · high-compliance environments without internal security review | teams that need a vendor-supported SLA · high-compliance environments without internal security review | teams that need a vendor-supported SLA · high-compliance environments without internal security review | teams that need a vendor-supported SLA · high-compliance environments without internal security review |
| OpenAgentSkill engagement | 0 views 0 install copies | 0 views 0 install copies | 0 views 0 install copies | 0 views 0 install copies |
| Install | $ npx skills add karastojko/mailio | $ npx skills add PHPMailer/PHPMailer | $ npx skills add Foundry376/Mailspring | $ npx skills add mail-in-a-box/mailinabox |