private-podcast-feed

name	private-podcast-feed
description	Use when publishing a private MP3+RSS feed for self-subscription. Covers itunes:block, token-prefixed URLs, ID3 CHAP/CTOC chapters for Overcast skip-ahead, and the Overcast refresh ping. Triggers: private podcast, RSS feed for Overcast, self-hosted podcast, private audio feed, MP3 RSS, personal podcast, chapter markers, Overcast ping, podcast XML, itunes:block.
globs	[]
compatibility	claude-code, cursor
license	MIT
metadata	{"author":"eins78","repo":"https://github.com/eins78/agent-skills","version":"1.1.0"}

private-podcast-feed

Publishes a private MP3+RSS feed for self-subscription in Overcast (or any podcast client). "Private" means URL obscurity via token prefix and itunes:block=Yes to keep it out of public indexes. Not cryptographic access control — the feed URL is the only secret.

1. podcast@2.0.1 Named Export

Use the named export — the default export does not work:

import { podcast } from "podcast";   // ✅ named — correct
import podcast from "podcast";        // ❌ default — fails at runtime (R3 gotcha)

2. itunes:block=Yes via customElements

The typed FeedITunes interface does not expose itunesBlock. The only correct path is the customElements array:

const feed = new podcast({
  title: "My Private Feed",
  feedUrl,
  siteUrl: new URL(feedUrl).origin,
  customElements: [{ "itunes:block": "Yes" }],  // keeps feed out of public indexes
});

Without this, the feed may be discovered and indexed by Apple Podcasts search.

3. Token-Prefixed URL

Serve the feed at /p/<32-hex>/feed.xml. The 32-hex token is 128 bits of URL obscurity — anyone with the URL can subscribe.

https://your-host.com/p/5042a002464df562718eef84ac1316f5/feed.xml

Generate a token: openssl rand -hex 16

Gitignore .token if you store the raw token on disk. Note: this is NOT access control — the URL is the only barrier. Do not store sensitive content.

4. ID3 CHAP/CTOC Chapter Frames

Inject chapters post-ffmpeg via mutagen so Overcast shows skippable chapters:

# inject_chapters.py (bundled in text-to-speech skill)
inject(mp3_path, [
    {"start_ms": 0,       "title": "Introduction"},
    {"start_ms": 125000,  "title": "Section Two"},
])

Chapters must be strictly increasing by start_ms. End time of chapter N is set to start time of N+1; last chapter ends at the MP3's total duration.

If using the text-to-speech skill, chapters are injected automatically during render when chapters.json is present.

5. Static-Hosting Pattern

The feed needs an HTTPS host returning correct content-types:

feed.xml   → Content-Type: text/xml
*.mp3      → Content-Type: audio/mpeg

Any static hosting platform works (Cloudflare R2, S3, Caddy, nginx). Podcast clients revalidate the feed URL periodically — the URL must be stable.

6. Overcast Refresh Ping

After publishing a new episode, ping Overcast to trigger an immediate fetch:

${CLAUDE_SKILL_DIR}/scripts/ping-overcast.sh https://your-host.com/p/<token>/

The script is idempotent — safe to call on every feed regeneration. It pings https://overcast.fm/ping?urlprefix=<encoded-prefix> and exits 0 on HTTP 2xx.

7. Sanity Verification

# Feed responds with correct type
curl -I <feed-url>

# itunes:block is set
curl -s <feed-url> | grep "itunes:block"   # must print "Yes"

# Item count
curl -s <feed-url> | xmllint --xpath 'count(//item)' -

# MP3 URL responds
curl -I <mp3-url>   # expect: HTTP/2 200, content-type: audio/mpeg