AI Agent action fails with FirebaseException type cast error (Web + Tablet)

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Current Behavior

Cloud call error:sessionCreatorAssistant
TypeError: Instance of 'FirebaseException': type 'FirebaseException' is not a subtype of type 'JavaScriptObject'

Expected Behavior

The AI Agent action should successfully call the Anthropic API (Claude Haiku 4.5) and return the extracted JSON fields (formation, formateur, date_debut, date_fin, nombre_participants) to populate the form fields. Instead, the action fails silently with a FirebaseException type-cast error before any request reaches Anthropic (confirmed via Anthropic Console showing "Last used: Never").

Steps to Reproduce

1. Create an AI Agent (Chat type, Provider: Anthropic, Model: Claude Haiku 4.5) with a System Message that returns structured JSON
2. Add a button with an action chain: Show Snack Bar → AI Agent (call the agent) → Rebuild Page
3. Run in Test mode (desktop or tablet)
4. Fill in the input field and click the button
5. Open browser DevTools Console
6. Observe the error on click, and no fields get populated

Additional verification steps taken:

• Regenerated the Anthropic API key and updated it in the agent config — still fails identically
• Redeployed the agent after the key change (status: "Deployed")
• Checked Google Cloud Logs for the project's own Cloud Function (unrelated sessionCreatorAssistant function) — 0 requests received, confirming the call never reaches my own backend
• Reproducible on both desktop browser and tablet browser

Reproducible from Blank

• The steps to reproduce above start from a blank project.

Bug Report Code (Required)

IT40ksmBw4t1ofVG7s7TbcF7/So5JjN7R4I30dVraCgoIYyuOpl/evWkQxNtTfW/TH9ce0SmmXMBp/+MhYSWKfJdYDSrfqpJ+ZBuVjz/cE+Xa5OBDKieR2pSQOVjJnK11sK42BFvOftvdXdk2WWmHOiUQgrcNYztIlFISq/LZO4=

Visual documentation

Environment

- FlutterFlow version: (see top of editor, or "Help" menu > "About")
- Platform: Web
- Browser name and version: Chrome (latest)
- Operating system and version affected: macOS

Additional Information

This is blocking a client-facing feature (AI-assisted session creation form) in production.