Future: per-post-type syndication routing engine

[RCowles]

Stub — flesh out after additional Connection_Providers exist and a routing engine has more than one axis to route along.

Internal tracking: DOTCOM-16923

Context

Today FOSSE syndicates everything to every connected provider. That's the right default for the MVP, but POSSE in practice is more nuanced — different content shapes belong on different networks:

• Photos → Pixelfed + Bluesky, not email.
• Long-form essays → Mastodon (full text) + Bluesky (teaser-thread, already shipped via Long_Form_Strategy) + email newsletter.
• Status-format short notes → all networks.
• Replies → only the network being replied to.
• Drafts marked "private fediverse only" → AP only, never atproto.

We already have one axis of this: Long_Form_Strategy is a per-post-shape projector. A routing engine generalizes that pattern into a matrix:

                        | AP | atproto | email | nostr | ...
post-format=status      | ✓  |   ✓     |       |   ✓   |
post-format=image       | ✓  |   ✓     |       |   ✓   |
long-form               | ✓  |  teaser |   ✓   |       |
post_type=cpt:bookmark  |    |         |       |   ✓   |

Mechanically: a Routing_Strategy projector that reads a fosse_routing_rules option (or per-post-type meta) and short-circuits each provider's "should this post syndicate?" decision. Same shape as Object_Type and Long_Form_Strategy, just one layer up.

Why deferred

• Premature without more than one provider axis to route along — today we have AP + atproto and the only meaningful per-shape distinction (long-form) is already covered.
• Adding a routing UI before more providers exist would design for a matrix that doesn't exist yet.
• Unified post-type selection across AP + Atmosphere is the prerequisite — it normalizes the which post types federate at all? question into one place. Routing is the next layer.

When to flesh this out

When at least one of the following is true:

• A third Connection_Provider (Threads / Nostr / email) is in flight or shipped.
• A user asks for per-post-type targeting (e.g. a CMS-heavy partner with multiple custom post types).
• Unified post-type selection is done and the natural next question is "OK, but I want CPT X on AP only."

Out of scope here

• Adding new providers themselves → tracked in Future: additional Connection_Providers (Threads, Nostr, email newsletter) #42.
• Per-post manual override UI in the composer (cross-network send status work is adjacent).
• Routing based on draft/visibility state (private posts, password-protected, etc.) — could fold in here or stay separate.

References

• The existing Long_Form_Strategy projector — single-axis precedent for this shape.
• https://www.citationneeded.news/posse/ — framing on selective syndication.
• https://indieweb.org/POSSE — u-syndication / per-target advertising.

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This is intentionally a long-horizon idea — not on our near-term plate, but external interest and contributions are welcome. Discussion happens here; internal Automattic tracking lives in Linear.