Test state consistency across agent steps

Name the authority for each piece of state

LangGraph documents graph state and application stores as separate persistence surfaces. Rubrex recommends assigning authority at field level: the service owns inventory, the user owns the requested change, and a tool result records one observation at a known time. None should silently replace another because it appears later in a conversation.

Use a synthetic workspace record containing owner, status, and version. The agent reads version four and prepares a status update. Before it writes, another actor changes the owner and produces version five. Define which fields the proposed update depends on and whether it must be recomputed.

Evidence: LangGraph: Persistence [1]

Introduce a stale observation at a controlled step

Pause after the initial read, perform the external update, then resume the agent. Capture the read version, proposed patch, write precondition, and final record. A full-record replacement can erase the new owner even when the agent intended only to change status; a narrow patch still needs appropriate preconditions for dependent fields.

Run another case where the user corrects the requested status while a slow tool response is in flight. The late response should retain its historical identity rather than overwrite the newer instruction. Observe both the final service record and the assistant’s explanation of which request it completed.

Test conflicts without blocking independent changes

Create an unrelated field change that should not invalidate the status update under the chosen contract. Compare it with a material change, such as an owner transition that removes the caller’s authority. This separates deliberate conflict handling from a blanket rule that rejects every version difference.

Record stale-write denials, successful merges, lost updates, and unresolved conflicts. Preserve before-and-after records rather than relying on success responses. Include a normal unchanged record control and an unavailable refresh path; the latter should produce a bounded stop when the application cannot establish a safe current state.

Choose a consistency rule for the actual operation

Accept the update workflow when it preserves independent changes, revalidates material dependencies, and explains unresolved conflicts. Use version checks, narrow updates, or transactions appropriate to the storage system; the generated plan should not be the only place where a precondition exists.

Retain field-level dependencies in the tool contract and add conflict cases whenever the workflow gains another writer or cache. A successful test establishes behavior for the chosen record and timing pattern. It does not establish universal serializability, but it gives the release owner concrete evidence about a common source of silent agent errors.

Common questions