## ADDED Requirements

### Requirement: Each critical phase has an explicit checkpoint

SM Flow SHALL require an explicit checkpoint before a critical phase can be considered complete.

#### Scenario: Phase completes normally

- **WHEN** the agent finishes a critical phase such as Phase 0, Phase 0.5, Phase 1, Phase 2, Phase 2.5, or Phase 2.9
- **THEN** it reports the current phase, the capability source used, the produced artifacts, the satisfied exit conditions, and any unresolved blockers

#### Scenario: Checkpoint is missing

- **WHEN** a critical phase has produced artifacts or conclusions but no explicit checkpoint summary
- **THEN** the phase SHALL NOT be treated as complete for purposes of entering the next phase

### Requirement: Capability declaration is part of phase completion

SM Flow SHALL treat skill or fallback declaration as part of the phase completion condition.

#### Scenario: Native skill or local protocol is used

- **WHEN** a phase depends on a named capability such as `openspec-propose`, `grill-with-docs`, `zoom-out`, or `openspec-apply-change`
- **THEN** the agent states whether it used a native skill, a local `SKILL.md`, or a fallback protocol

#### Scenario: Fallback is used

- **WHEN** a phase falls back from a named capability
- **THEN** the agent records the target capability, the reason it was unavailable, the fallback protocol name, and the downgrade risk

#### Scenario: Declaration is omitted

- **WHEN** no capability source is declared for a phase that requires one
- **THEN** that phase SHALL NOT be considered complete