Bug type

Regression (worked before, now fails)

Beta release blocker

No

Summary

After upgrading to 2026.4.5, images shared in Slack stopped being visible to the agent. Downgrading to 2026.4.2 immediately restored the behavior.

Steps to reproduce

1. Upgrade OpenClaw to 2026.4.5.
2. Send an image file in Slack to the agent.
3. Observe that the agent cannot see the image (silently dropped).
4. Downgrade to 2026.4.2 — image is visible again immediately.

Expected behavior

In 2026.4.2, images shared via Slack (url_private_download) were
fetched correctly and visible to the agent. The Bearer token was
preserved across the redirect from files.slack.com.

Actual behavior

Images shared in Slack are silently dropped and not visible to the agent.
No error is shown. The fetch returns an HTML login page (url_private_download
redirects without Authorization header), which is detected and discarded
at actions-ClxauASC.js line 135.

OpenClaw version

2026.4.5 (3e72c03)

Operating system

Ubuntu 24.04

Install method

npm global (--prefix ~/.npm-global)

Model

openai-codex/gpt-5.4

Provider / routing chain

openclaw -> anthropic-->openai

Additional provider/model setup details

No response

Logs, screenshots, and evidence

Slack Socket mode. The regression is unrelated to the model/provider — 
it occurs in the Slack file fetch layer (actions-ClxauASC.js) before 
any LLM call is made. Confirmed by source code inspection:
Authorization header is stripped on redirect (line 52), causing 
url_private_download to return HTML instead of the image binary.
Fix: preserve Bearer token for redirects within files.slack.com 
in SLACK_MEDIA_SSRF_POLICY.

Impact and severity

Affected: All Slack users on 2026.4.5 using Socket mode
Severity: High (blocks workflow — agent cannot see any images shared in Slack)
Frequency: 100% reproducible — every image share fails
Consequence: Agent silently ignores all Slack image attachments with no error message

Additional information

Last known good version: 2026.4.2 (d74a122)
First known bad version: 2026.4.5 (3e72c03), introduced with the SSRF redirect fix.
Workaround: downgrade to 2026.4.2 via:
npm install -g [email protected] --prefix ~/.npm-global && openclaw restart

Likely fix: in SLACK_MEDIA_SSRF_POLICY, preserve the Authorization: Bearer
header when following redirects whose destination hostname is files.slack.com
(same trusted domain as the original request target).