Legacy default parity¶

This is the executable specification for issue #179. The rows live in symfonic.migration.LEGACY_DEFAULT_ROWS; tests/migration/test_legacy_defaults.py pins that every legacy field is present and that each one has either a same-turn legacy/native comparison or an existing owner.

FrameworkConfig defaults do not all start work. “Inert” means the field does not independently run a behaviour; it is recorded here so an adopter does not try to recreate a behaviour that the legacy agent did not run.

Legacy field or active companion	Trigger	Kernel composition / result	Evidence or owner
`auto_hydrate`	bound store and scope	candidate: `memory_capabilities` + `PromptingCapability`	gap, #188: native-only test
`auto_consolidate`	`MemoryExtractorPort`	candidate: `memory_capabilities(..., extractor=...)`	gap, #185: native-only test
`spreading_activation`	`AssociationSource`	candidate: `SpreadingActivation` through memory factory	gap, #188: native-only test
`lazy_tooling`	HMS prompt, procedural skills, tools	gap	#185
`enabled_layers`	memory retrieval	candidate: default `RetrievalPolicy`	gap, #188: default-value comparison only
`skill_auto_approve`	promotable skill	gap	#185
`streaming_enabled`	always	`Agent.stream()`	verified: same-turn deterministic stream completes on both paths
`experimental_tool_decorator`	never	retained no-op; `@symfonic_tool` is unconditional	config source
`phase_12_action_type_from_tool_calls`	phase-12 extraction	gap	#185
`messages_cache_policy`	provider cache dialect	gap	#187
`manifest_cache_position`	stratigraphic prompt mode	gap	#187
`system_prefix_cache_ttl`	compatible provider cache	gap	#187
`tool_result_recall_mode`	tool-result history	gap	#188
`activation_log_mode`	activation runs	gap	#188
`prompt_layer_mode`	legacy prompt path	gap	#187
`hms_budget_mode`	HMS prompt assembly	gap	#187
`memory_extract_cadence`	every turn; default `1`	no prompt-cadence consumer	gap, #187
`entity_linker_extractor`	`enable_entity_linker=True`	inactive until that flag	#186
`nightly_nap_cron`	never	operator recommendation, not engine scheduling	config source
`phase_12_llm_model`	LLM phase-12 extraction	gap	#185
`otel_service_name`	`otel_enabled=True` and an OTEL sink	inactive until OTEL is composed	#191
`working_memory_recent_turns`	`ConversationSource`	candidate: memory factory `conversation=`/`recent_turns=`	gap, #188: native-only test
`quick_nap_interval`	`ConsolidationCoordinator`	candidate: memory factory `consolidation=`	gap, #185: native-only test

The verified subset contains only streaming. It deliberately has no memory, prompting, retrieval, write, or consolidation stages:

from symfonic.migration import SUPPORTED_DEFAULT_BEHAVIORS, compose_legacy_defaults

agent = compose_legacy_defaults(
    provider,
    behaviors=SUPPORTED_DEFAULT_BEHAVIORS,
)

The runnable import-shaped example is examples.migration_parity.composed_defaults.build_agent. A bare compose_legacy_defaults(provider) reports every unresolved field and all missing deployment dependencies in one error. Neither outcome means issue #179 is ready to close.