ledgr stores several hashes and JSON payloads so runs, sweeps, promotion records, and later walk-forward artifacts can say what executed without confusing runtime lookup details with concrete feature identity.
Run and config identity
config_hash identifies the execution config after removing store-local
paths, run-local IDs, and diagnostic declaration-order fields. It remains
sensitive to execution inputs such as snapshot identity, universe, strategy,
parameters, feature definitions, timing model, cost identity, opening state,
and seed.
feature_set_hash identifies the resolved concrete feature definitions by
hashing the set of feature fingerprints. It changes when concrete feature
parameters change, even if user-facing aliases stay the same.
feature_params_hash identifies the feature parameter list supplied to a
run or candidate. It records user parameter inputs; feature_set_hash
records the resolved feature definitions produced from those inputs.
Alias identity
alias_map_json stores the active alias map used for runtime lookup, plus
declaration-level identity mappings when available. The concrete lookup map
lets ctx$features(id) resolve aliases to feature IDs after reopening.
alias_map_hash hashes declaration-level alias identity, not concrete
feature parameter values. Alias names and declaration semantics affect this
hash; resolved feature parameter values belong to feature_set_hash.
alias_map_order records declaration order for diagnostics and display. It
is not part of config_hash.
Cost identity
cost_plan_json is the canonical serializable cost-model plan stored in the
execution config. cost_model_hash is the SHA-256 hash of that plan. These
fields are execution identity and are forward dependencies for
walk-forward candidate identity; they do not implement walk-forward by
themselves.
Where to inspect
In-session runs expose feature_set_hash at
bt$config$features$feature_set_hash. Durable stores expose it through
ledgr_run_info() and ledgr_run_list(). Sweep candidates expose
candidate-level feature identity in their row-level provenance and
reproduction keys.