| name | kindle |
| description | Send a downloaded book file to a Kindle via the zlib CLI, and walk the user through the one-time SMTP/Amazon setup it needs. Use when the user wants to deliver an ebook to their Kindle, configure Kindle delivery, or fix a failed Kindle send. |
| argument-hint | <file-path> |
| allowed-tools | Bash, Read, AskUserQuestion |
| homepage | https://github.com/heartleo/zlib |
| repository | https://github.com/heartleo/zlib |
| author | heartleo |
| license | MIT |
| user-invocable | true |
/zlib:kindle
Deliver an already-downloaded file to the user's Kindle through the zlib CLI, and handle the one-time configuration it depends on. To find or download the book first, use the zlib skill; this skill takes it from a local file to the Kindle.
Preflight
zlib must be on PATH (command -v zlib) and the user logged in — but sending itself doesn't need a Z-Library session, only Kindle config. If the binary is missing, tell the user to install it (go install github.com/heartleo/zlib/cmd/zlib@latest).
Send — zlib kindle send <file>
Always pass the file path — bare zlib kindle send opens an interactive file picker you can't answer. With a path and no terminal it sends directly and exits, printing success or a clear SMTP error:
zlib kindle send ./books/dune.epub
zlib download <id> --send-to-kindle delivers in one step once Kindle is configured.
First check the config
Before sending, read ~/.config/zlib/kindle.json and check ZLIB_SMTP_PWD. If the file is missing, holds placeholder-looking values (e.g. mykindle@kindle.com, sender@gmail.com), or the password is unset, run the setup walkthrough below before sending. If it looks configured, just send and relay the result.
Configuring Kindle delivery — walk the user through it in conversation
Guide the user step by step — ask one question at a time, wait for each answer, then write the config yourself. Do not tell the user to edit files or run the wizard.
-
Ask for the Kindle receive address. "What's your Kindle address (xxx@kindle.com)? Find it under Amazon → Manage Your Content and Devices → Preferences → Personal Document Settings." It must be the Amazon-assigned address, not their normal email.
-
Ask for the sender email. Remind them it must be on Amazon's approved-sender list (same Personal Document Settings page) — otherwise Amazon silently drops the file even though SMTP reports success.
-
Derive SMTP from the sender domain — gmail.com → smtp.gmail.com:587, outlook/hotmail → smtp-mail.outlook.com:587, qq.com → smtp.qq.com:587, 163.com → smtp.163.com:465; anything else, ask. Then write the config yourself (create the directory if needed):
{"to":"<kindle-address>","from":"<sender-email>","smtp_host":"<host>","smtp_port":<port>}
-
Set the SMTP app password — the user edits the env file directly. Never ask for, paste, or echo the password in the chat, and never put it on a command line. zlib reads ZLIB_SMTP_PWD from ~/.config/zlib/.env at startup. Prepare the file and hand the user the exact path plus a one-click open command, then wait for them to confirm they saved it.
Create the file (if missing) with a template line and print its absolute path:
mkdir -p ~/.config/zlib
[ -f ~/.config/zlib/.env ] || printf '# zlib secrets — one KEY=value per line\nZLIB_SMTP_PWD=\n' > ~/.config/zlib/.env
chmod 600 ~/.config/zlib/.env
echo "Open and edit: $(cd ~/.config/zlib && pwd)/.env"
Tell the user to set ZLIB_SMTP_PWD=<app-password> on its own line and save. It must be an app password, not the account password — for Gmail: enable 2FA, generate at https://myaccount.google.com/apppasswords (16 chars; strip spaces). Give them a ready open command for their OS to run with the ! prefix:
- Windows:
! notepad "$USERPROFILE\.config\zlib\.env"
- macOS:
! open -t ~/.config/zlib/.env
- Linux:
! ${EDITOR:-nano} ~/.config/zlib/.env
Once the config and the saved password are in place, run the send and relay the result.
Errors
535 / 454 SMTP error — almost always a real account password (or none) instead of an app password, or the sender isn't allowed. Re-check step 4.- SMTP connection timeout — the network can't reach the SMTP host (e.g. Gmail blocked).
ZLIB_PROXY does not cover SMTP (it's a direct connection); the user needs a system-level VPN/TUN, or switch to a reachable provider (QQ/163). Probe with timeout 8 bash -c 'echo > /dev/tcp/<host>/<port>'.
- "Sent" but nothing arrives — the sender email isn't on Amazon's approved-sender list (step 2).
- Password reported missing after editing
~/.config/zlib/.env — check no stale ZLIB_SMTP_PWD in a working-directory .env is overriding it (working-dir wins over the global file); have the user fix whichever file applies. Older zlib builds load only the working-directory .env, so on those the user must put ZLIB_SMTP_PWD= in the .env of the directory the command runs in, and should upgrade.
