🐞 Bug Summary

Update Gateway and Get Gateway APIs return an empty tags list ([]) even though tags are present in the Postgres gateways.tags JSON column.

🧩 Affected Component

Select the area of the project impacted:

• mcpgateway - API
• mcpgateway - UI (admin panel)
• mcpgateway.wrapper - stdio wrapper
• Federation or Transports
• CLI, Makefiles, or shell scripts
• Container setup (Docker/Podman/Compose)
• Other (explain below)

🔁 Steps to Reproduce

1. Create a Gateway with tags via API (e.g., POST /gateways) using tags: ["Finance", "ml"].
2. Verify tags exist in Postgres for that gateway (e.g., SELECT tags FROM gateways WHERE id = '<gateway_id>';) and confirm the JSON contains tag values.
3. Update the same Gateway via API (e.g., PUT /gateways/{gateway_id}) and include tags: ["Finance", "ml"] (or update any other field—either way, tags remain present in DB).
4. Observe the response tags is [] even though the DB row still contains tags.
5. Call GET /gateways/{gateway_id} again
6. Observe the response tags is [] even though the DB row still contains tags.

🤔 Expected Behavior

If tags exist in the database for a gateway, GET /gateways/{gateway_id} (and the response from PATCH/PUT /gateways/{gateway_id}) should return those tags rather than an empty list.

📓 Logs / Error Output

Example response (200 OK) showing empty tags:

{
  "id": "<gateway_id>",
  "name": "my-gateway",
  "tags": []
}

🧠 Environment Info

You can retrieve most of this from the /version endpoint.

🧩 Additional Context (optional)

Tag normalization/validation converts every tag element to a string first (including non-string JSON items), which can cause stored tag objects / stringified dicts to normalize into invalid formats and be filtered out—resulting in [] even when the DB contains data. See TagValidator.validate_list() stringification at