azd ai agent init -m .../agent.yaml
...
v0.1.22-preview
...
ERROR: downloading agent.yaml: YAML content does not conform to AgentManifest format: yaml: unmarshal errors:
line 8: cannot unmarshal !!map into []interface {}

This happens when the agent.yaml is not a manifest (could be a definition).

We should handle this nicely and provide an error suggestion.