Endpoint workflow replacement

Slack files.upload method_not_supported newly created apps legacy files.upload deprecated files_upload_v2

The API returns method_not_supported/denial for a newly created app while an older app still works.

Slack file uploadCollaboration SaaS APIEndpoint workflow replacementslack_upload

Agent Quick Fix

Repair against the current Slack file upload contract, then keep the change narrow and source-backed.

Product: Slack file upload
Current-contract area: New Slack app denied legacy files.upload
Likely root cause: The API returns method_not_supported/denial for a newly created app while an older app still works.
Repair direction: Verifier checks sequencing, idempotency, and final resource visibility. Check channel visibility, metadata, and idempotency.

Symptom

The API returns method_not_supported/denial for a newly created app while an older app still works.

Why This Happens

The old endpoint can remain present in SDK types or historical examples even after new apps are denied or the endpoint is sunset.

Common Wrong Fixes

Changing local code without checking the current external contract.
Retrying the same install, build, or API call with no version/source change.
Applying a broad unsafe bypass when a narrow compatibility fix is available.

Codex Search Keywords

These are the search terms observed in a neutral Codex validation run for this failure shape.

Slack files.upload method_not_supported newly created apps legacy files.upload deprecated files_upload_v2
Slack files.upload deprecated new apps method_not_supported
https://api.slack.com/methods/files.upload
https://docs.slack.dev/changelog/2024-04-a-better-way-to-upload-files-is-here-to-stay

Source Trail