thrds (Python)

Declarative thread sync for Slack, Discord, and Bluesky.

Given a desired thread state (list of message contents), diffs against existing messages and applies minimal edits/posts/deletes to converge.

A TypeScript port (Slack subset) lives on the ts branch, published on npm as @rdub/thrds. Both impls share tests/fixtures/sync.json as the cross-language contract for the diff/edit/post/delete algorithm.

Install

pip install thrds            # Core only (zero deps)
pip install thrds[bsky]      # + Bluesky (atproto)

Slack and Discord clients use only stdlib (urllib) and curl subprocess respectively — no extra deps needed.

Usage

from thrds import SlackClient, Thread

slack = SlackClient(token="xoxb-...", channel="C0AQC2VKEJF")
thread = Thread(messages=["OP text", "Reply 1", "Reply 2"])

# Create new thread
result = slack.sync(thread)

# Update existing thread (edits changed messages, appends new, deletes extras)
result = slack.sync(thread, thread_ts="1775516040.743629")

Discord

from thrds import DiscordClient, Thread

discord = DiscordClient(token="your-bot-token", channel_id="1489279547689140505")
thread = Thread(messages=["OP text", "Reply 1", "Reply 2"])
result = discord.sync(thread, thread_id="1490821926288097503")

Bluesky

from thrds import BskyClient, Thread

bsky = BskyClient(handle="you.bsky.social", password="app-password")
thread = Thread(messages=["Root post", "Reply 1"])
result = bsky.sync(thread)

Bluesky doesn't support editing posts — the sync algorithm automatically falls back to delete+repost when content changes.

Linked summary threads

Post summary bullets that link to detail messages in the same thread:

from thrds import LinkedThread, Section

linked = LinkedThread(
    summary_prefix="# Daily Digest",
    sections=[
        Section(title="Topic A", summary="Brief summary", body="Full detail text..."),
        Section(title="Topic B", summary="Another summary", body="More details..."),
    ],
)

# Discord: summary bullets use [**Title**](url) markdown links
result = discord.sync_linked(linked, thread_id="...", guild_id="...")

# Slack: summary bullets use <url|*Title*> mrkdwn links
result = slack.sync_linked(linked, thread_ts="...")

Two-phase sync: posts all messages with placeholder links, then edits summaries with real links once message IDs are known.

Dry run / diff preview

result = slack.sync(thread, thread_ts="...", dry_run=True)
print(result.format_preview(color=True, prefix="thread: "))

thread: SKIP [0] (unchanged)
thread: EDIT [1]
thread:   -old message text
thread:   +new message text
thread: POST [2]
thread:   +entirely new message

Each Action carries prior_content (for EDIT/DELETE) alongside content, enabling colored unified-diff output via action.format().

Sync algorithm

Given desired messages M and existing thread messages N:

1. Delete extras from the end (backwards — replies before OP)
2. Edit overlapping messages where content changed (skip unchanged)
3. Post new messages at the end

Foreign (non-editable) messages — e.g. human replies in a bot thread — are automatically skipped. The sync only operates on the bot's own messages, leaving everyone else's untouched.

Features

• Foreign message preservation: Non-bot messages in threads are skipped during sync (no more cant_update_message errors)
• Rate limit handling: Slack 429 retry with Retry-After, configurable pace and jitter between API calls
• Edit rate limit fallback: Discord's 30046 error (edit limit on old messages) triggers automatic delete+repost
• Linked summary threads: sync_linked() for summary-with-links threads on Discord and Slack
• Diff preview: Action.format() and SyncResult.format_preview() for colored diff output
• Orphan guard: Slack delete() checks for thread replies before deleting (raises OrphanedRepliesError)
• Unfurl/embed suppression: Slack link previews and Discord embeds suppressed via options
• Discord system message filtering: Thread starter messages filtered from list_messages
• Bot token prefix: Discord Bot prefix auto-prepended
• Metadata support: Slack message metadata passthrough

Used by

• hudcostreets/nj-crashes — Slack crash-notification threads (SlackClient.sync())
• Open-Athena/marin-discord — Discord summary threads (DiscordClient.sync_linked())

API

SyncResult

@dataclass
class SyncResult:
    thread_id: str          # thread_ts (Slack), thread channel ID (Discord), AT URI (Bluesky)
    message_ids: list[str]  # Per-message IDs
    actions: list[Action]   # What was done: Edit, Post, Delete, Skip

Action

@dataclass
class Action:
    type: ActionType        # SKIP, EDIT, POST, DELETE
    index: int
    message_id: str | None
    content: str | None         # Desired text (POST, EDIT, SKIP)
    prior_content: str | None   # Previous text (EDIT, DELETE)

SyncOptions

Option	Default	Description
dry_run	False	Print actions without executing
pace	0.0	Seconds between mutating API calls
jitter	0.0	Random additional delay (0 to jitter) added to pace
suppress_embeds	False	Discord: suppress link previews
suppress_unfurls	True	Slack: suppress link previews