Summary

Two new MCP tool capabilities are needed to support automated incremental stream testing and configuration workflows:

1. Modify stream sync settings on an existing connection — A tool that can safely change the sync mode (e.g., full_refresh → incremental) for a specific stream or set of streams on a connection, including setting the cursor field and destination sync mode.

2. Refresh/re-discover the catalog on an existing connection — A tool that triggers a discover operation on a connection (equivalent to clicking "Refresh source schema" in the UI), so the catalog reflects the latest connector capabilities after a version pin or upgrade.

Motivation

When adding incremental support to an existing connector stream, the typical workflow involves:

1. Publishing a pre-release connector version
2. Pinning the pre-release to a test connection
3. Refreshing the catalog so the connection picks up the newly-advertised incremental support
4. Changing the stream sync mode from full_refresh to incremental
5. Running syncs to verify

Steps 3 and 4 currently have no safe MCP tool support. The underlying mechanisms exist in PyAirbyte (replace_connection_catalog in api_util.py and the withRefreshedCatalog: true flag on web_backend/connections/get), but:

• They are not exposed as MCP tools
• Raw catalog manipulation by an LLM is risky — pulling the full catalog, transforming a specific stream, and pushing it back requires careful handling that should be encapsulated in a purpose-built tool with proper validation
• The ops MCP has get_connection_catalog (read-only) but no corresponding write tool

Proposed Tools

1. set_stream_sync_mode (or similar)

• Inputs: connection_id, stream_name, sync_mode (incremental | full_refresh), optionally destination_sync_mode and cursor_field
• Behavior: Safely modifies only the specified stream(s) in the connection's syncCatalog, validates the configuration is legal (e.g., the stream actually supports incremental), and applies the change
• Safety: Should validate that the requested sync mode is in the stream's supportedSyncModes before applying

2. refresh_connection_catalog (or similar)

• Inputs: connection_id
• Behavior: Triggers a discover operation on the connection's source with the currently-pinned connector version, updating the connection's catalog with the latest stream definitions and supported sync modes
• Implementation note: This likely wraps a call to web_backend/connections/get with withRefreshedCatalog: true, or an equivalent mechanism

Context

• Requested by Aaron ("AJ") Steers (@aaronsteers) during development of the add-incremental-stream-support skill (ai-skills PR #112)
• The skill currently documents UI-based workarounds (Option A) and new-connection workarounds (Option B) because these tools don't exist yet
• Thread context: https://airbytehq-team.slack.com/archives/C07N1EGSM8E/p1773766113926719

Devin session