[Alfazal007]

Repeated resource operation IDs currently call the provider twice. Add kernel-owned replay gates for execution, tool-call, resource-operation and message identities, backed by a host-owned durable ReplayStore. Atomic claims block concurrent duplicates, conflicting input is rejected, and retained terminal results are replayed without repeating effects.

ADR 0028 defines tenant scoping, canonical fingerprints, pending/failed/interrupted states, permanent identity tombstones, result expiry, fenced crash recovery and ambiguous external effects. Standard resource tools derive provider IDs from their full execution identity; messaging claims both direct and nested deliveries. Testkit supplies an isolated in-memory adapter.

Protocol v1 activation is opt-in through SharedOSKernelOptions.replayStore; omission preserves legacy unprotected behavior. Production hosts must install a durable adapter. ADR 0019 now freezes protocol "1" at the 1.0.0-preview shape. Mandatory activation remains a future coordinated semantic protocol migration; this change does not assume epoch 2 or /v2 routes. No exactly-once claim is made for external systems. Grant reservation and audit transactions remain outside this change.

Validation:

• 35 focused replay/testkit tests passed with one worker, covering the original duplicate-effect probe, all four identity paths, HTTP, races, conflicts, tenant isolation, outages, cancellation, retention, result replay and recovery.
• 21 selected existing kernel/runtime regression tests passed with one worker.
• pnpm typecheck, pnpm format:check and git diff --check passed.
• pnpm check was attempted, then stopped at the user's request to avoid heavy suites on this machine. The full conformance and final aggregate checks are not claimed as passed.

Pre-existing/environment issues: the initial check could not start because dependencies were absent (resolved with a frozen install). TypeDoc's Git repository detection ignores worktrees whose .git is a file, removing source links even for unchanged APIs; regenerated API references preserve the existing canonical links. These are separate from replay test results.

Merge integration: merged main at d9e2ea4 and resolved the generated API conflicts. Replay scoping now follows trusted AccessContext.executionId, and the executor normalizes context execution identity before fingerprinting and claiming a turn. Added focused regressions for both cases.

Post-merge validation: 37 replay/testkit tests plus 6 selected turn-isolation regressions passed, all with one worker. Type checking, formatting and conflict/whitespace checks passed. No full test or conformance suite was run, honoring the machine-resource constraint.