Follow-up to merged #531 and completed upstream cycle #526; related to the broader rollback contract in #200. Verified exact rewind already works for eligible managed OpenCode sessions. This issue tracks its remaining native compatibility limits, not a reimplementation of that work.
Remaining cases:
- Experimental native plan-file mode is ineligible: native forks regenerate session identity without copying the plan file derived from creation time/slug. Ordinary plan/history/resume remain usable.
- Externally managed servers are ineligible because their API does not expose the runtime flags needed to prove plan-file mode is disabled.
- Historical checkpoints without an immutable, verified native snapshot cannot be backfilled from relative turn counts.
Investigate native APIs for complete plan-context forks and observable server capabilities. Add support where exact source/target proof can be retained. For old checkpoints, enable reconstruction only if native history can prove the original Pylon boundary; otherwise document that limitation and the next native capability needed. Revisit when OpenCode adds fork support for external plan context, runtime capability introspection, or verifiable historical boundary reconstruction.
Acceptance:
- Supported new cases preserve full inference context, permissions, original source compensation, idempotent retry and same-incarnation restart recovery.
- Unsupported cases remain explicitly unavailable; do not change runtime flags, silently copy workspace files, or substitute relative counts to bypass proof.
- Cover compaction, delayed callbacks, interruption and restart boundaries with focused regressions; retain ordinary plan/Stop/resume behavior.
- Independently review the final diff and require green CI. Document supported native versions and any remaining upstream blockers with a concrete revisit trigger.
Existing evidence: #531 includes 363 focused tests and an isolated OpenCode 1.18.29 native import/fork smoke. No live model or rendered UI validation was claimed. Future runtime checks must use isolated state and respect the existing browser/account authorization boundaries.
Model: GPT-6. Harness: Codex.
Follow-up to merged #531 and completed upstream cycle #526; related to the broader rollback contract in #200. Verified exact rewind already works for eligible managed OpenCode sessions. This issue tracks its remaining native compatibility limits, not a reimplementation of that work.
Remaining cases:
Investigate native APIs for complete plan-context forks and observable server capabilities. Add support where exact source/target proof can be retained. For old checkpoints, enable reconstruction only if native history can prove the original Pylon boundary; otherwise document that limitation and the next native capability needed. Revisit when OpenCode adds fork support for external plan context, runtime capability introspection, or verifiable historical boundary reconstruction.
Acceptance:
Existing evidence: #531 includes 363 focused tests and an isolated OpenCode 1.18.29 native import/fork smoke. No live model or rendered UI validation was claimed. Future runtime checks must use isolated state and respect the existing browser/account authorization boundaries.
Model: GPT-6. Harness: Codex.