OAuth is now functional on Evergreen spawn hosts. When a user completes the authentication in the Evergreen UI while creating the host, there will be a valid temporary access token in the oauth block of .evergreen.yml, like:

```
cat /root/.evergreen.yml
user: sean.lyons
api_server_host: https://evergreen.corp.mongodb.com/api
ui_server_host: https://evergreen.mongodb.com
spawn_host_id: i-0bbe33671cdb7f802
task_id: mongodb_mongo_master_enterprise_amazon_linux2023_arm64_all_feature_flags_sharding_stepdown_fcv_upgrade_downgrade_jscore_passthrough_0_linux_enterprise_35930633af93ddc0d3b9c90002650f4e72230f3d_26_06_05_07_55_10
project_id: mongodb-mongo-master
oauth:
issuer: https://dex.prod.corp.mongodb.com
client_id: login
connector_id: oidc
do_not_use_browser: true
spawn_host_access_token:
accesstoken: <REDACTED> # <-- LOOKS LIKE THIS
tokentype: Bearer
refreshtoken:
expiry: 2026-06-05T17:36:15.538Z
expiresin: 0
```
This is sufficient for the script to make authenticated calls to the Evergreen API.