Feature proposal: Bridge replies from unbridged users as actual mentions (implicit consent via interaction)

[molind]

The Problem

Currently, when an unbridged Bluesky user replies to a bridged Mastodon user's post, the Mastodon user receives a DM notification digest (thanks for the recent unbridged notifications feature! 🎉). However, they can't easily continue the conversation — they'd need to go to Bluesky to reply, or hope the Bluesky user opts into the bridge.

This creates friction for cross-network conversations. The Bluesky user already engaged with bridged content, clearly intending to communicate, but the conversation hits a dead end.

Proposed Solution

Treat replying to a bridged post as implicit consent for that specific reply to be bridged back.

When an unbridged Bluesky user replies to a bridged Mastodon post:

1. Bridge that reply as an actual Mastodon mention/reply (not just a DM notification)
2. The Mastodon user sees it in their notifications and can reply normally
3. The conversation continues naturally

This would be conversation-scoped, not account-scoped — we're not bridging their entire account, just their voluntary participation in a specific thread they chose to join.

Why This Makes Sense

1. Expectation alignment — When someone replies to a post clearly marked as bridged from Mastodon, they reasonably expect the original author to see and respond to their reply

2. Analogous to email — If I email someone, I expect they might reply. Replying is participation.

3. Already public content — The reply is already public on Bluesky. We're just delivering it to the person it was addressed to.

4. Reduces friction — Currently, meaningful cross-network conversations require both parties to understand and opt into bridging. This is a high bar for casual interactions.

Possible Implementation

For replies from unbridged users to bridged posts:

• Create a temporary/ephemeral representation for the unbridged user (or use existing @handle@bsky.brid.gy format)
• Deliver the reply as a proper ActivityPub Note with inReplyTo
• Include clear attribution that this is a bridged reply from Bluesky
• Optionally: add a footer like "Reply via Bridgy Fed or on Bluesky"

Addressing Consent Concerns

I understand Bridgy Fed chose opt-in for good reasons after community feedback. This proposal is different:

Full account bridging	Reply bridging (this proposal)
Bridges all posts	Bridges only specific replies to bridged content
User may not expect it	User explicitly engaged with cross-network content
Ongoing commitment	One-time, conversation-scoped

Potential safeguards:

• Only bridge replies, not original posts from unbridged users
• Include clear "via Bridgy Fed" attribution
• Allow Bluesky users to opt-out via #nobridge in bio
• Only bridge replies to posts that are clearly marked as bridged

Questions for Discussion

1. Has this been considered before? I searched issues but may have missed prior discussion.
2. Are there technical blockers I'm not seeing?
3. Would this conflict with Bridgy Fed's consent philosophy, or is conversation-scoped implicit consent acceptable?
4. Would a simpler version work — e.g., creating proper mentions only for replies, while still requiring opt-in for the unbridged user to see responses?

[snarfed]

Hi @molind, thanks for reaching out, and for the detailed writeup! This has indeed been discussed before, primarily in #1535 . The discussion there probably has answers to most or all of your questions. There's also some related discussion in #1471 .

You'll probably also be interested in #2042 . Stay tuned for more news there soon! cc @anujahooja