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
Mailspring is the strongest overall pick here because it has a 100/100 readiness score and fits Workflow automation.
Strongest overall
Mailspring
Use this as a leading candidate, then validate the README and install path in your own agent stack.
Fastest prototype
Mailspring
Best first install candidate based on install readiness and adoption.
Freshest repo
Mailspring
Most recent maintenance signal among this shortlist.
| Signal | Gromox Groupware server backend for the grommunio Distribution, supporting MAPI/HTTP, RPC/HTTP, EWS, IMAP, POP3 protocols, PHP-MAPI bindings, and import from PST/OST/MSG/CDFV2/TNEF, EML/ICAL/VCF, Kopano, Zarafa | Mailspring :love_letter: A beautiful, fast and fully open source mail client for Mac, Windows and Linux. | BillionMail BillionMail gives you open-source MailServer, NewsLetter, Email Marketing — fully self-hosted, dev-friendly, and free from monthly fees. Join the discord: https://discord.gg/asfXzBUhZr | 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 | 70/100 Strong | 100/100 Excellent | 100/100 Excellent | 100/100 Excellent |
| Decision verdict | 69/100 Prototype first Prototype with this skill first; keep a fallback candidate ready. | 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 | 243 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 | 15K stars Verified outcomes are shown on each skill page |
| Freshness | Jun 15, 2026 | Jun 15, 2026 | Jun 11, 2026 | May 24, 2026 |
| Use-case fit | ||||
| Workflow fit | ||||
| Platform hints | C++, Calendar, Claude Code | JavaScript, Email, Claude Code | Go, 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 grommunio/gromox | $ npx skills add Foundry376/Mailspring | $ npx skills add Billionmail/BillionMail | $ npx skills add mail-in-a-box/mailinabox |