Check the combined version when two AI coding agents contribute to the same release. A clean merge tells you that the version-control system combined the changes without an unresolved textual conflict. It does not establish that the changes agree about a shared field, default or user-visible behavior.
This guide starts after separate contributions exist. The useful artifact is a short record of their interactions and the checks run on the combined candidate. It is different from deciding whether to use parallel agents or giving each one a separate workspace.
- 01Test the combined candidate.Results from separate branches refer to different code states.
- 02Inspect shared assumptions.Changes in different files can disagree about the same interface or default.
- 03Keep resolution intent visible.A conflict resolution should preserve the required behavior, not merely remove markers.
01 — Review the points where contributions meetReview the points where contributions meet
Use this table for a release with multiple contributions. An interface contract means the names, values and behavior one part of the program expects from another. The review should follow those contracts across files, not stop at the list of paths changed by both agents.
| Interaction | Why separate checks can miss it | Combined-candidate check |
|---|---|---|
| Shared field or type | Producer and consumer changed independently. | Pass a combined-version value across the interface. |
| Defaults and missing values | One change broadens inputs while another assumes a value exists. | Exercise the newly allowed absence or default. |
| Configuration | Both changes depend on different settings or environments. | Verify the candidate under the intended configuration. |
| Generated artifacts | Source edits and generated output came from different states. | Regenerate as prescribed and inspect consistency. |
| Conflict resolution | A chosen side can discard the other requirement. | Check the final behavior against both accepted intentions. |
| Cross-feature journey | Each feature passes alone while their interaction fails. | Exercise the user path that crosses the contributions. |
02 — What a merge actually resolvesWhat a merge actually resolves
Git’s merge documentation explains how non-overlapping changes can be incorporated and how conflicting changes are presented for resolution. That is a rule for combining file content. The inference for agent work is straightforward: code that combines cleanly still needs checks of the resulting behavior.
Playwright’s testing guidance recommends testing the behavior visible to users. Applied here, that means exercising the interaction across both changes on the same candidate. A browser test is appropriate for a browser interaction; other systems need checks at their own user or service boundary.
Neither source estimates how frequently coding agents introduce integration problems. The examples below are hypothetical design cases, not observations from a production incident or a comparison of agent products.
03 — Follow a value through both changesFollow a value through both changes
Imagine one agent changes an API field from “name” to “displayName.” Another independently adds an export feature that reads “name.” The edits can sit in different files and merge without a conflict. The API branch may pass its updated tests, while the export branch passes against its older fixture. In combination, the exported label is missing.
The useful check starts with a record created or read through the combined API and follows it into the export. Keep the relevant implementation real. If the export test substitutes the old response shape, it can conceal the disagreement. The test-data reference explains how to label that simulated boundary.
Check defaults and absent values too. One contribution might make a field optional while another assumes it is populated. A successful example with every field filled does not exercise that interaction.
04 — Treat conflict resolution as a new changeTreat conflict resolution as a new change
When a conflict is visible, compare the purpose of both contributions with the final behavior required. Selecting one side wholesale can discard a valid requirement. Removing conflict markers is an editing step; the resulting code is a new candidate that needs its own review.
Keep the resolution note short: the conflicting assumption, the chosen behavior and the check that demonstrates it. If generated files are involved, use the project’s prescribed generator where appropriate and inspect the resulting changes. Hand-combining generated output can leave it inconsistent with its source.
Our worktree isolation guide addresses keeping concurrent edits apart. Isolation makes separate work manageable, but the combined candidate still has to reconcile the assumptions that crossed those workspaces.
05 — Record the combined version and its evidenceRecord the combined version and its evidence
Identify the source contributions, their starting point and the final candidate being checked. Run the project’s required validation, then the focused checks justified by the interactions in the table. If the target branch changes again, decide which results remain applicable and which need rerunning.
The bug-report evidence guide is useful when an interaction fails: preserve the triggering inputs, expected result and observed behavior on the combined version. Send that specific failure to the responsible agent rather than asking both agents to “double-check everything.”
Finish with one accountable integration decision. Separate agents can explain their contributions, but the release owner needs evidence about the combined result. This is where the parallel task becomes one product again.
06 — DecisionWhat to do next
Accept one combined result.
Trace the interactions between contributions, inspect any resolution and verify the final candidate. Keep the version identifier beside the evidence so separate successes do not get mistaken for a checked release.
For implementation support, explore our AI transformation services.