--- name: send-to-kindle description: >- Use when getting a document onto an Amazon Kindle — which delivery routes still work, what format to produce, and why a delivery can silently fail. Kindle-only; nothing here applies to Kobo, reMarkable or other e-readers. Triggers: send to Kindle, put this on my Kindle, read on Kindle, Kindle email address, sendtokindle, personal documents, sideload EPUB, Kindle didn't receive it, kindle.com address, Kindle highlights, My Clippings. globs: [] compatibility: claude-code, cursor license: MIT metadata: author: eins78 repo: https://github.com/eins78/agent-skills version: "0.1.0" --- # send-to-kindle Delivering a document to a Kindle. Covers what to produce, how it gets there, and the two failure modes that give no error message. Producing the file is the `pandoc` skill's job — `scripts/md2kindle-epub.sh` turns markdown into a suitable EPUB. This skill starts at "the file exists". **Everything below is service behaviour, and it moves.** Between 2022 and 2026 Amazon stopped accepting MOBI, started accepting EPUB, killed USB download of purchased books, and retired Word's Send-to-Kindle button. Statuses here are **as of 2026-08**; re-verify before relying on a dated claim. ## Produce EPUB, not PDF | | | |---|---| | **EPUB** | Reflowable — text re-wraps to the reader's font size and margins. Kindles do not render EPUB natively; Send-to-Kindle converts it server-side into the device's own format (KFX/AZW3) on delivery, which is what buys reflow, resizable type, and a native TOC. Free, no local tooling. | | **PDF** | Fixed-layout. A PDF page is a fixed canvas — on a 6" screen it either shrinks to illegible or needs constant pan/zoom. Right for print, wrong for reading. An A5 print booklet is roughly 60% wider than a Paperwhite's visible area. | | **MOBI / AZW** | Not accepted as *input* since August 2022. Don't reach for an old MOBI recipe. | | **AZW3 (locally converted)** | Only needed for the USB path — see below. | ## Delivery routes (status as of 2026-08) | Route | Status | Notes | |---|---|---| | **Send-to-Kindle email** (`…@kindle.com`) | Works | The default. Wireless, works over a phone hotspot. See the three facts below | | **Web upload** (sendtokindle.com, drag-and-drop) | Works | Manual, but no sender allowlist to trip over | | **Kindle mobile app → "Import file"** | Works | Only useful if the reader reads on the phone | | **USB sideload into `documents/`** | Works | A raw `.epub` copied over USB is **not indexed** by the Kindle library — convert to AZW3 locally first (e.g. Calibre). Email delivery gets that conversion for free. Unaffected by the 2025 removal of USB *download* for purchased Kindle Store books, which is a different thing | | **Send to Kindle desktop app** | Being retired | Kindle for PC and the Windows desktop app shut down 2026-06-30. Email and web upload do not depend on it | | **Send to Kindle from Microsoft Word** | Retired 2026-02-09 | The button is gone; web upload is unaffected | | **Wireless delivery to older hardware** | Cut off for pre-2013 devices | The May-2026 cutoff hit Paperwhite 1 and older only. 2018-era hardware and newer keep full wireless delivery | ## Sending by email — three facts 1. **Send the file as an email attachment** to the reader's Send-to-Kindle address. Nothing else in the message matters. 2. **Addresses are per device, not per account.** An account with several registered Kindles has a separate ingress address for each, so delivery is granular. Amazon-facing *device names* are user-set and can be misleading — pick the target by a stable identifier (the address itself, or the device serial), never by display name. 3. **The sender address must be pre-approved** on the account's Approved Personal Document E-mail List. Mail from an unapproved sender is **dropped silently — no bounce, no error, no delivery.** This is the single most likely cause of "I sent it and nothing arrived". The allowlist is separate from the ingress address; both live under *Manage Your Content and Devices → Preferences → Personal Document Settings*. ## Size ceilings | Route | Ceiling | |---|---| | Email attachment | **~50 MB** — widely-circulated community figure, not confirmed against an official Amazon page. Verify on the Personal Document Settings page if it matters | | Web upload | ~200 MB, same caveat | Text documents will not come near either. A document bundling archived source captures plausibly could. ## Highlights only come back one way Anything delivered via Send-to-Kindle is a **personal document**, not a Kindle Store purchase, and Amazon's cloud highlight ecosystem is structurally closed to it: | Route | Covers personal documents? | |---|---| | `documents/My Clippings.txt` on the device | **Yes — the only route.** Plain text, trivially parseable, but retrieval requires physically connecting the device over USB. No wireless path exists for this file | | `read.amazon.com/notebook` (web Notebook) | No — Kindle Store purchases only | | Per-book "Export Notes and Highlights" | No — same scope, and manual anyway | | Readwise | No — its docs explicitly exclude files sent via Send-to-Kindle | So the USB cable is not a convenience fallback here; it is the only mechanism. Plan around a manual step, or do not promise highlight round-tripping. ## Common Mistakes | Symptom | Cause | Fix | |---------|-------|-----| | Sent it, nothing arrived, no bounce | Sender not on the approved list | Add the exact sending address under Personal Document Settings | | Arrived on the wrong person's Kindle | Targeted by device display name | Target by ingress address or serial; names are user-set and often stale | | Reader has to pan and zoom every page | A PDF was sent | Send EPUB and let Send-to-Kindle convert it | | Copied an `.epub` over USB, it never appears in the library | Raw EPUB isn't indexed on-device | Convert to AZW3 locally, or use email delivery instead | | Checkboxes render as blank gaps | Task-list HTML `` elements were emitted | See the `pandoc` skill — build the EPUB with `task_lists` disabled | | Waiting for highlights to sync | Personal documents never reach the cloud | USB + `My Clippings.txt`, or nothing | ## What this skill deliberately does not do - **It does not send anything.** No sender script, no AppleScript, no SMTP helper, and no configuration contract for one. The send step is the three facts above, performed by a human in a mail client. - **It carries no addresses.** Ingress addresses, approved senders, device serials, and keychain account names are personal values that belong in the operator's own private workspace, never in a published skill.