v0.4.0

Plain text, anonymous SMTP, and agent skills

Pop can now send plain text emails, work with anonymous SMTP relays, and teach your fav AI agent (like Crush 💘) how to send mail from the terminal!

Thanks to @jficz, you can skip Markdown-to-HTML rendering by passing --plaintext:

pop --plaintext \
    --from me@example.com \
    --to you@example.com \
    --subject "Hello!" \
    --body "Just plain text."

You can also set POP_PLAINTEXT=true. Plain text delivery works with both SMTP and Resend.

Courtesy of @c-tonneslan, it supports SMTP relays that don't require authentication. Set the SMTP host as usual and leave the username and password unset:

export POP_SMTP_HOST=corpo.lan
export POP_SMTP_PORT=25

Finally, Pop ships with a skill teaching Crush 💘 and other Agent Skills-supporting harnesses how to send mail, along with installers for Crush, Claude Code, Codex, Cursor, and Pi:

pop skill
pop install-skill crush
pop install-skill claude
pop install-skill codex
pop install-skill cursor
pop install-skill pi

Thanks to everyone who contributed, and thanks for using Pop!

Charm ✉️

Changelog

New!

• 6193324: feat: Allow plaintext e-mails (#125) (@jficz)
• 6a0c5f3: smtp: allow more anonymous relays (#167) (@c-tonneslan)
• 79b6dc0: Skills: add Pi as an install-skill target (@meowgorithm)
• 0a7d2ac: Skills: add install-skill subcommand to install skill for AI agents (@meowgorithm)
• f1b761b: Skills: add pop skill command to print a skill definition (@meowgorithm)

Docs

• b7ef6c0: docs: add plaintext option to README and skill (@Amolith)

Other stuff

• 2f53667: AGENTS: add AGENTS.md (@meowgorithm)
• 181e4ac: CI: allow automatic Go toolchain selection (@Amolith)
• e7111b4: OAuth: fix regression when oauth is revoked that would prevent start (@meowgorithm)
• f1fb35c: README: add info about skills (@meowgorithm)
• 18d5953: README: correct URL in workflow badge (@meowgorithm)
• a0d245c: README: fix typo (@meowgorithm)
• 359de90: Skills: cleanup install-skill error formatting and output (@meowgorithm)
• 29d72d5: Skills: help text copyedit (@meowgorithm)
• 1a29201: build: bump Go to 1.26.5 (@Amolith)

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Verifying the artifacts

First, download the checksums.txt file and the checksums.txt.sigstore.json file files, for example, with wget:

wget 'https://github.com/charmbracelet/pop/releases/download/v0.4.0/checksums.txt'
wget 'https://github.com/charmbracelet/pop/releases/download/v0.4.0/checksums.txt.sigstore.json'

Then, verify it using cosign:

cosign verify-blob \
  --certificate-identity 'https://github.com/charmbracelet/meta/.github/workflows/goreleaser.yml@refs/heads/main' \
  --certificate-oidc-issuer 'https://token.actions.githubusercontent.com' \
  --bundle 'checksums.txt.sigstore.json' \
  ./checksums.txt

If the output is Verified OK, you can safely use it to verify the checksums of other artifacts you downloaded from the release using sha256sum:

sha256sum --ignore-missing -c checksums.txt

Done! You artifacts are now verified!

Thoughts? Questions? We love hearing from you. Feel free to reach out on X, Discord, Slack, The Fediverse, Bluesky.