Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden of behavioral disclosure but offers minimal information. It doesn't indicate whether this is a mutation (likely, given 'add'), what permissions are needed, if it's idempotent, what happens on duplicate edges, or what the response looks like. For a tool with 6 parameters and no output schema, this is severely inadequate.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.