Summary
Using Claude (via the WeWeb MCP integration) to build and edit frontend workflows, I’ve hit a consistent blocker: any workflow containing a Supabase Select or Call Postgres Function action gets rejected by the MCP tool with a “action type not found” error — even though these same action types are already running successfully, live, in my project (added originally through the normal Editor UI).
This means AI-assisted workflow editing basically doesn’t work for anything involving the database, which is most of what a real app does.
What I’m seeing
When Claude tries to create or edit a workflow that includes a Supabase action, it fails with:
The generated workflow is not valid, please retry: [WRONG_ACTION_TYPES]
Action "supabase/select" not found in the list of all workflow actions
Action "supabase/rpc" not found in the list of all workflow actions
The odd part: this happens even when the exact same action, copied byte-for-byte from an existing workflow that is currently working in the live app, is submitted back unchanged. It’s not a mistake in what’s being sent — it’s the validator not recognizing the action type at all.
It’s also inconsistent — it worked for me a couple of times early on, then started failing on effectively everything afterwards, including page-level workflows and workflows that hadn’t changed structurally from ones that had previously gone through fine.
This isn’t something I hand-built — it was added via the normal action picker in the Editor (“Database | Call Postgres Function”), and it’s currently calling a real Postgres function and returning a result correctly. Same story for supabase/select (“Database | Select”) — plenty of working examples already in the app.
What Support said
I raised this with WeWeb support and got two useful but slightly conflicting answers:
- Database | Select — confirmed as a normal, documented, supported workflow action.
- RPC / stored procedures — support said this isn’t currently a built-in workflow action per the docs, and is only tracked as a feature request.
That second point doesn’t match what I’m actually seeing in my own project — the RPC action exists, is selectable in the Editor UI today, and is working in production. I pointed this out and support’s follow-up was essentially “the documentation doesn’t describe a ‘Call Postgres Function’ action, so there’s no indication it’s officially supported” — which is a documentation-coverage answer, not a “this doesn’t exist” answer. I’ve got the live API response showing otherwise.
Is anyone else seeing MCP-based workflow edits fail specifically on Supabase actions (Select or RPC)?
- Is the MCP tool’s action-type validator meant to stay in sync with what the Editor actually supports, or is there a known gap between them right now?
- For those of you with RPC/“Call Postgres Function” actions already in your apps — can you confirm whether this is officially supported, deprecated-but-still-working, or something that’s not meant to be relied on long-term?
Not blocking my actual app (everything that was already built keeps working fine) — but it means AI-assisted editing can’t currently touch anything involving the database, which is a big limitation if you’re trying to use Claude/MCP to iterate quickly.
Happy to share more detail (project structure, exact repro steps, full error payloads) if it helps get this looked at.
