# Computegraph Integration
This page names lower-level graph storage terms for implementers who need them.
They are not required terminology for the getting-started path.
`tidu` stores graph transform results using `computegraph` data structures. The
important public wrappers are `LinearizedGraph` and `PrimitiveGraph`, but
advanced runtimes may need raw access.
## Storage Terms
- `Graph` is the lower-level graph container.
- `LocalValueId` identifies a value within one graph container.
- `ValueKey` identifies an input or derived value across graph boundaries.
- `ValueRef` represents an operation input, either local or external.
- `OperationRole` marks primal operations and linear operations.
## Why These Appear
Graph transforms often need to reference primal values from a linear rule. Those
references are represented as external graph values at the storage layer.
Downstream runtimes can use `as_graph()` or `into_graph()` when compiling,
materializing, or merging transform results with their existing graph execution
pipeline.