symfonic.capabilities.governance.errors

errors

Governance composition errors (T3.4.4).

All three fire at composition time, never mid-turn. A pipeline that is mis-ordered, mis-declared, or built out of unknown stages is a deployment defect; discovering it on the first governed turn would mean discovering it in production.

GovernanceError

Bases: Exception

Base class for every governance composition failure.

StageContractError

Bases: GovernanceError

A stage object declares something other than what the rulebook does.

The likeliest instance is a stage quietly declaring FAIL_OPEN for a concern the rulebook declares fail-closed — a disarmed guard that would otherwise look identical to a working one.

StageOrderError

Bases: GovernanceError

The composition contradicts the rulebook's order.

Duplicates, inversions, and phase reversals all land here. Ordering is the one property no individual stage can enforce.

UnknownStageError

Bases: GovernanceError

A stage name the rulebook does not declare.

Raised rather than defaulted: a stage nobody declared has no declared phase and no declared failure mode, so the pipeline cannot say what it would do when the stage breaks.