anchor.diff:  
   {:toc}
   
  -## Starting an Agent
  +## Starting an agent
   
   <%= render 'agent/v3/help/start' %>
   
  -## Setting Tags
  +## Setting tags
   
   Each agent has tags (in 2.x we called this metadata) which can be used to group and target the agents in your build pipelines. This way you're free to dynamically scale your agents and target them based on their capabilities rather than maintaining a static list.
   
  
positive.code: </section>
  
  
  ## The Queue Tag
  
  The `queue` tag works differently from other tags, and can be used for isolating jobs and agents. See the [agent queues documentation](queues) for more information about using queues.
  
  ## Sourcing Tags from Amazon Web Services
  
  You can load an Agent's tags from the underlying Amazon EC2 instance using `--tags-from-ec2-tags` for the instance tags and `--tags-from-ec2` to load the EC2 metadata (e.g instance name and machine type).
  
  ## Sourcing Tags from Google Cloud
  
  You can load an Agent's tags from the underlying Google Cloud metadata using `--tags-from-gcp`.
  
negative.code: env BUILDKITE_AGENT_TAGS="docker=true,ruby2=true" buildkite-agent start
  ```
  
  ## Agent targeting
  
  Once you've started agents with [tags](#setting-tags) you can target them in the build pipeline using agent query rules.
  
  Here's an example of targeting agents that are running with the tag `postgres` and value of `1.9.4`:
  
  