As Salesforce gears up for Agentforce, technical debt and documentation has suddenly become a high priority. You can't manage what you can't see. Which is why a metadata dictionary is a critical tool.

Also, you will need a metadata dictionary to manage all the Agentforce dependencies.  The power of Agentforce is the ability to reuse existing metadata across agents. But you don't want one of the team updating Apex or a Flow and not realizing that it is being used by one or more agents.  It not might break the org, but it will definitely change the behavior of the agent.

So what is a "Metadata Dictionary"?  And can I afford one?

https://elements.cloud/blog/how-metadata-dictionaries-can-help-reduce-technical-debt/