## MODIFIED Requirements

### Requirement: Verifier SHALL consume explicit verification inputs
The Verifier SHALL receive explicit verification inputs rather than inferring them only from raw conversation history.

#### Scenario: gatekeeper result available to Verifier
- **WHEN** the system prepares verifier inputs from Executor output
- **THEN** the payload SHALL include `gatekeeper_result`
- **AND** `gatekeeper_result.status` SHALL be one of `pass`, `warn`, or `fail`
- **AND** `gatekeeper_result` SHALL include `failed_rules`, `warnings`, and `errors`

### Requirement: Verifier SHALL be observable
The Verifier's verdict SHALL be persisted for observability.

#### Scenario: gatekeeper result written to self_evaluation
- **WHEN** the Verifier evaluation is persisted
- **THEN** `diagnosis_session.self_evaluation.verifier_evaluation` SHALL include `gatekeeper_result`
- **AND** existing verifier fields such as `verdict`, `facts_checked`, `executor_output_parse_status`, and `tool_trace_summary` SHALL be preserved

## ADDED Requirements

### Requirement: Executor Gatekeeper SHALL validate deterministic structured-output failures
The system SHALL run deterministic Gatekeeper checks after Executor output parsing and before Verifier model execution.

#### Scenario: schema rule rejects removed fields
- **WHEN** Executor structured output contains `diagnosis_summary` or `user_facing_answer`
- **THEN** `gatekeeper_result.status` SHALL be `fail`
- **AND** `gatekeeper_result.failed_rules` SHALL contain `schema.executor_v2`

#### Scenario: schema rule rejects missing evidence bindings
- **WHEN** a confirmed claim has no `evidence_bindings`
- **THEN** `gatekeeper_result.status` SHALL be `fail`
- **AND** `gatekeeper_result.failed_rules` SHALL contain `schema.executor_v2`

#### Scenario: invocation rule rejects fabricated invocation ids
- **WHEN** a claim evidence binding references a `source_invocation_ids` value that is not present in current-session `tool_invocation` rows
- **THEN** `gatekeeper_result.status` SHALL be `fail`
- **AND** `gatekeeper_result.failed_rules` SHALL contain `evidence.invocation_ref`

#### Scenario: invocation rule rejects tool name mismatch
- **WHEN** a claim evidence binding references an existing invocation id
- **AND** the binding `tool_name` does not match the invocation's persisted `tool_name`
- **THEN** `gatekeeper_result.status` SHALL be `fail`
- **AND** `gatekeeper_result.failed_rules` SHALL contain `evidence.invocation_ref`

#### Scenario: valid structured output passes initial gatekeeper rules
- **WHEN** Executor emits `executor_evidence_v2`
- **AND** each claim has evidence bindings pointing to current-session invocations with matching tool names
- **THEN** `gatekeeper_result.status` SHALL be `pass`
- **AND** `gatekeeper_result.failed_rules` SHALL be empty