Crate pe_graph 

pe-graph — Graph execution engine for Potential Expectations

Implements the core graph primitives that agent topologies are built on:

• StateGraph — declarative graph definition with typed nodes and edges
• CompiledGraph — validated, executable graph with invoke() / resume()
• GraphConfig — execution configuration (thread ID, recursion limit, etc.)
• Checkpointer — trait for durable state persistence
• GraphRegistry — named storage for compiled graphs

The execution engine uses the Pregel BSP model (Bulk Synchronous Parallel): nodes execute in parallel supersteps with snapshot isolation, writes are collected and applied atomically between steps.

Depends only on pe-core plus tokio and futures for async execution.

Re-exports

pub use checkpointer::CheckpointMeta;

pub use checkpointer::Checkpointer;

pub use checkpointer::InMemoryCheckpointer;

pub use checkpointer::PendingWrite;

pub use command::Command;

pub use compiled::CompiledGraph;

pub use compiled::ExecutionOutcome;

pub use config::GraphConfig;

pub use graph::StateGraph;

pub use matrix_hook::ConvergenceRecorder;

pub use matrix_hook::DefaultMatrixHook;

pub use matrix_hook::MatrixHook;

pub use matrix_hook::MatrixHookHandle;

pub use matrix_hook::RoutingResolver;

pub use pending_writes::PendingWrites;

pub use registry::GraphRegistry;

pub use retry::RetryPolicy;

pub use retry::with_retry;

pub use snapshot::StateSnapshot;

Modules

checkpointer

Checkpoint persistence — trait + in-memory implementation.

command

Graph commands – how users send input back to a paused graph.

compiled

Compiled graph — the user-facing execution handle.

config

Graph execution configuration.

graph

Graph definition — StateGraph<S> builder and validation.

matrix_hook

Matrix integration hook — trait for the optional matrix layer.

pending_writes

Pending writes tracking for fault tolerance within a superstep.

phase_store

Phase state store – re-exported from pe-core for convenience.

registry

Graph registry — named storage for compiled graphs.

retry

Retry policy – per-phase retry with exponential backoff and jitter.

snapshot

State snapshots for checkpoint inspection and time travel.

Structs

CheckpointData

Internal wrapper for checkpoint serialization.

PhaseStateStore

Stores serialized phase state for nodes, keyed by phase enum TypeId.

Enums

PhaseStoreError

Errors from phase state serialization/deserialization.

Constants

END

Reserved graph exit point

START

Reserved graph entry point