Graph and Vector Are Tools, Not a Religion

The industry is having a storage argument. The interface has already moved.

The agent does not open a notebook. It calls tools. MCP is how you hand it the estate without building a UI for every question. The harness is the point. Storage is a substrate.

Similarity is not identity

Vector stores answer similarity. They find the messy text: the ticket, the call note, the contract clause that feels like this. They are lossy on purpose. They do not know that this account is the parent of that one, or that this identifier was retired in 2019.

Graphs answer named structure. They know the relationship, the provenance, the policy edge, the allowed join. They stop an agent inventing a customer out of two similar embeddings. They are also how you attach a field to a purpose and a legal basis instead of dumping a table into a context window.

You need both. Vector without graph is a search engine with amnesia about identity. Graph without vector is a rigid schema that cannot read the unstructured half of the company. Treating them as a bake-off is a category error.

One door, one kill switch

The MCP surface should expose both, under the same taxonomy, with the same identity and the same kill switch. The operator should not have to pick a vendor religion before they can ask who churned and why.

On a PII continent the graph is also the allow-list. Vector indexes only what that purpose may see. The tool refuses the rest. That is the envelope. The comfort ritual of resequenced IDs is what teams do when they do not have one. That ritual feels safe. It is not.

None of this restores the ticket queue. The queue rationed access because the warehouse was the only interface. Tools replaced it. Policy has to ride on the tool, or the freedom is a breach with a nice prompt.

Give the agent both. Vector for what feels like this. Graph for what is the same thing, and for which join is allowed. One taxonomy. One door. The model does not get to be the policy.

Related: Share the Taxonomy or Do Not Bother, Anonymised Feels Comfortable. It Is Not., and The Ticket Queue Was a Rationing System.