kandev/docs/plans/acp-context-reset-runtime-configuration/task-01-restore-runtime-configuration.md

id, title, status, wave, depends_on, plan, spec

id	title	status	wave	depends_on	plan	spec
01-restore-runtime-configuration	Restore the complete runtime configuration	done	1		plan.md	../../specs/ui/requirements/acp-model-configuration-summary.md

Task 01: Restore the Complete Runtime Configuration

Acceptance

• Both context-reset paths capture one immutable effective SessionRuntimeConfig before provider defaults can publish.
• Both paths restore the model, permission mode, and each non-model configuration option in deterministic order.
• If a captured field is rejected, Kandev reports an error and publishes no ready or reset-success event.
• The lifecycle does not expose the fresh session as ready until every captured field is restored.

Verification

cd apps/backend && go test -race -run 'TestManager_(ResetAgentContext|RestartAgentProcess)_(ReappliesSessionRuntimeConfig|FailsClosedOnRuntimeConfigRestore)$' ./internal/agent/runtime/lifecycle

Write the regression tests first. The fast-path test must fail because current code restores the fresh default mode and omits configuration options.

Files likely touched

• apps/backend/internal/agent/runtime/lifecycle/manager_interaction.go
• apps/backend/internal/agent/runtime/lifecycle/manager_interaction_test.go

Dependencies

None.

Parallelism

Sequential. This task owns the backend behavior required by every later task.

Inputs

• Reset behavior in the linked spec
• docs/decisions/2026-08-18-context-reset-preserves-runtime-configuration.md
• Plan sections Capture one effective runtime configuration, Restore one effective runtime configuration, and Regression fixture
• models.SessionRuntimeConfig and effectiveSessionRuntimeConfig
• Existing model policy, session initialization layers, and workspace-rebind option filtering

Risks

• Do not let provider-default events mutate the captured map.
• Do not send model or mode values again through SetConfigOption.
• Do not fabricate cache state after a rejected provider operation.
• Preserve RuntimeConfigOptionsSet semantics for an authoritative empty option set.

Output contract

Report the RED result, the configuration precedence, the apply order, changed files, and exact test results. Update this task and plan.md in the same conversation.

Results

RED: the focused lifecycle command failed all four new regression tests before the implementation. The fast path omitted configuration-option requests and the restart path did not restore the captured model/options; both rejection cases incorrectly returned success.

The effective snapshot starts with profile values, applies persisted session runtime values and explicit overrides through WorkspaceInfo, then falls back to the live model and mode caches when a persisted field is absent. The option map is cloned before reset or restart. Restoration order is model, permission mode, then non-model options sorted by option ID. A rejected mode or option marks the execution failed and keeps AgentBootReady and AgentContextReset unpublished until all fields succeed.

Changed files:

• apps/backend/internal/agent/runtime/lifecycle/manager_interaction.go
• apps/backend/internal/agent/runtime/lifecycle/manager_profile.go
• apps/backend/internal/agent/runtime/lifecycle/manager_interaction_test.go
• apps/backend/internal/agent/runtime/lifecycle/manager_interaction_runtime_config_reset_test.go

Verification:

• cd apps/backend && go test -race -run 'TestManager_(ResetAgentContext|RestartAgentProcess)_(ReappliesSessionRuntimeConfig|FailsClosedOnRuntimeConfigRestore)$' ./internal/agent/runtime/lifecycle — 4 passed.
• cd apps/backend && go test -race ./internal/agent/runtime/lifecycle — 1,911 passed.

PR fixup coverage added after review:

• Live ConfigOptions snapshots are authoritative when available, so removed persisted options are not restored and newer provider values win over stale profile values.
• Option-only and explicitly settled empty catalogs satisfy the fresh-session readiness gate without waiting for a model list.
• The mock can reject model restoration, and the reset test verifies that mode, options, ready events, and reset-success events are not applied or published.
• Reset failures persist the failed executor-running status before returning.

Additional verification:

• Focused fixup tests — 4 passed.
• cd apps/web && pnpm e2e:run tests/workflow/workflow-step-proceed.spec.ts -- --grep "preserves session settings across context reset" — 1 passed.
• cd apps/backend && make lint — 0 issues.