anchor.diff:  
   <h3 class="h3-caps">BUILDKITE_HOOKS_PATH</h3>
   
  -The value of the `hooks-path` [agent configuration option](https://buildkite.com/docs/agent/v3/configuration). The value cannot be modified as an environment variable.
  +The value of the `hooks-path` [agent configuration option](/docs/agent/v3/configuration). The value cannot be modified as an environment variable.
   
   Example: `"/etc/buildkite-agent/hooks/"`
   
  
positive.code: 
  <h3 class="h3-caps">BUILDKITE_GIT_CLEAN_FLAGS</h3>
  
  The value of the `git-clean-flags` [agent configuration option](https://buildkite.com/docs/agent/v3/configuration). The value can be modified by exporting the environment variable in the `environment` or `pre-checkout` hooks.
  
  Example: `"-ffxdq"`
  
  <h3 class="h3-caps">BUILDKITE_GIT_CLONE_FLAGS</h3>
  
  The value of the `git-clone-flags` [agent configuration option](https://buildkite.com/docs/agent/v3/configuration). The value can be modified by exporting the environment variable in the `environment` or `pre-checkout` hooks.
  
  Example: `"-v"`
  
  <h3 class="h3-caps">BUILDKITE_GIT_SUBMODULES</h3>
  
  The opposite of the value of the `no-git-submodules` [agent configuration option](https://buildkite.com/docs/agent/v3/configuration). The value cannot be modified as an environment variable.
  
  Values: `"true"` and `"false"`
  
  
negative.code: 
  <h3 class="h3-caps">BUILDKITE_SSH_KEYSCAN</h3>
  
  The opposite of the value of the `no-ssh-keyscan` [agent configuration option](/docs/agent/v3/configuration). The value cannot be modified as an environment variable.
  
  Values: `"true"` and `"false"`
  
  <h3 class="h3-caps">BUILDKITE_S3_ACCESS_KEY_ID</h3>
  
  The access key ID for your S3 IAM user, for use with [private S3 buckets](/docs/agent/v3/cli-artifact#using-your-own-private-aws-s3-bucket). The variable is read by the `buildkite-agent artifact upload` command, and during the artifact upload phase of [command steps](/docs/pipelines/command-step#command-step-attributes). The value can only be set by exporting the environment variable in the `environment`, `pre-checkout` or `pre-command` hooks.
  
  Example: `"AKIAIOSFODNN7EXAMPLE"`
  
  <h3 class="h3-caps">BUILDKITE_S3_ACCESS_URL</h3>
  
  The access URL for your [private S3 bucket](/docs/agent/v3/cli-artifact#using-your-own-private-aws-s3-bucket), if you are using a proxy. The variable is read by the `buildkite-agent artifact upload` command, and during the artifact upload phase of [command steps](/docs/pipelines/command-step#command-step-attributes). The value can only be set by exporting the environment variable in the `environment`, `pre-checkout` or `pre-command` hooks.
  
  Example: `"https://buildkite-artifacts.example.com/"`
  
  <h3 class="h3-caps">BUILDKITE_S3_ACL</h3>
  
  The Access Control List to be set on artifacts being uploaded to your [private S3 bucket](/docs/agent/v3/cli-artifact#using-your-own-private-aws-s3-bucket). The variable is read by the `buildkite-agent artifact upload` command, and during the artifact upload phase of [command steps](/docs/pipelines/command-step#command-step-attributes). The value can only be set by exporting the environment variable in the `environment`, `pre-checkout` or `pre-command` hooks.
  
  Default: `"public-read"`
  
  <h3 class="h3-caps">BUILDKITE_S3_DEFAULT_REGION</h3>
  
  The region of your [private S3 bucket](/docs/agent/v3/cli-artifact#using-your-own-private-aws-s3-bucket). The variable is read by the `buildkite-agent artifact upload` command, and during the artifact upload phase of [command steps](/docs/pipelines/command-step#command-step-attributes). The value can only be set by exporting the environment variable in the `environment`, `pre-checkout` or `pre-command` hooks.
  
  Default: `"us-east-1"`
  
  <h3 class="h3-caps">BUILDKITE_S3_SECRET_ACCESS_KEY</h3>
  
  The secret access key for your S3 IAM user, for use with [private S3 buckets](/docs/agent/v3/cli-artifact#using-your-own-private-aws-s3-bucket). The variable is read by the `buildkite-agent artifact upload` command, and during the artifact upload phase of [command steps](/docs/pipelines/command-step#command-step-attributes). The value can only be set by exporting the environment variable in the `environment`, `pre-checkout` or `pre-command` hooks.
  
  Example: `"wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY"`
  
  