Slack is a manifest-driven source — connectors/http/manifests/slack.yaml
declares its resources, auth, and pagination against the shared grammar in
connectors/http/manifest/; no Slack-specific Go code exists. See
HTTP for how the manifest mechanism works.
It’s also the only bundled SaaS manifest that declares an incremental:
block, so it’s the best reference for what incremental support looks like at
the manifest level.
Auth
A bot or user OAuth token (bearer auth), plus an optional
conversation_types config value (default public_channel) that controls
which conversation types conversations enumerates — set it to include
private_channel, mpim, or im if the token has access.
Resources
Nine resources, statically discovered:
conversations is deliberately membership-aware: it calls
users.conversations rather than a workspace-wide channel list, because
conversations.history (used by messages) rejects a channel the bot can
see but hasn’t joined with not_in_channel. Enumerating only channels the
token is actually a member of keeps discovery and extraction consistent.
Incremental sync
messages is the one resource in the bundled catalog with an incremental:
block:
Each run reads a channel’s messages newer than the last checkpointed ts
(Slack’s per-message timestamp, which doubles as a numeric cursor), injects
it as the oldest query parameter on the next run, and checkpoints under
messages_since per conversation.
Error handling
Slack’s Web API returns HTTP 200 even on failure, signaling errors via an
error field in the JSON body. The manifest’s connection-wide
defaults.response.error block (path: error, when_present: true) makes
every resource check that field and fail the request instead of silently
ingesting an error payload as if it were data.
Modes
ModeFull and ModeIncremental (see HTTP). 
