GcpSkillRegistry.get_skill() always fails with 302: Agent Registry media download redirect to GCS signed URL is not followed

[codebee-aoki]

🔴 Required Information

Describe the Bug:
GcpSkillRegistry.get_skill() always fails when downloading the skill archive. The Agent Registry API serves the revision media download (?alt=media) as a 302 redirect to a short-lived GCS signed URL. The httpx.AsyncClient created in _create_httpx_client does not follow redirects (httpx default), and httpx's response.raise_for_status() raises on 3xx responses, so _make_request surfaces the redirect as an error and the skill archive can never be downloaded:

RuntimeError: API request failed with status 302: ...

This makes skill loading from the GCP Agent Registry (e.g. via SkillToolset.load_skill) unusable against the real API.

Steps to Reproduce:

1. Install google-adk==2.7.1.
2. Point GcpSkillRegistry at an Agent Registry project/location containing any skill.
3. await registry.get_skill(name="<any-skill>").
4. The metadata request succeeds, then the ?alt=media media download fails with the RuntimeError above.

Expected Behavior:
The client follows the 302 redirect to the GCS signed URL and downloads the skill archive. (This is safe: httpx removes the Authorization header when following a cross-origin redirect, so the OAuth bearer token is not forwarded to the signed-URL host.)

Observed Behavior:
RuntimeError: API request failed with status 302: ... raised from _make_request for every skill download.

Environment Details:

• ADK Library Version (pip show google-adk): 2.7.1
• Reproduced both locally and with an agent deployed on Agent Engine runtime. Also independently confirmed by another user on 2.7.1 (Linux / Python 3.12), who has been working around it with a client-side monkey-patch since 2.6.2 — see fix: follow redirects when downloading skills in GcpSkillRegistry #6824 (comment) (PR comment thread).

Model Information:

• Are you using LiteLLM: No
• Which model is being used: N/A (client-side registry download; no model involved)

Fix

PR #6824 is open with the fix: pass follow_redirects=True to both httpx.AsyncClient constructions in _create_httpx_client (plain and mTLS/ssl-context branches). It includes unit tests and has been verified end-to-end against a real Agent Registry catalog (the identical change applied as a monkey-patch on Agent Engine runtime restores skill downloads).

[llalitkumarrr]

Hello @codebee-aoki ,

Thank you for your contribution. We were able to reproduce the bug and test your fix which resolves the issue. The pull request is currently under review and will be merged if approved. Thank you for your patience in the meantime.