diff --git a/plugins/voyage/tests/fixtures/brief-effort-high.md b/plugins/voyage/tests/fixtures/brief-effort-high.md
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+---
+type: trekbrief
+brief_version: "2.1"
+created: 2026-05-14
+task: "Fixture: high-effort all phases (v5.1.1 runtime test)"
+slug: brief-effort-high
+project_dir: .claude/projects/2026-05-14-brief-effort-high/
+research_topics: 0
+research_status: complete
+auto_research: false
+interview_turns: 4
+source: fixture
+phase_signals:
+  - phase: research
+    effort: high
+    model: opus
+  - phase: plan
+    effort: high
+    model: opus
+  - phase: execute
+    effort: high
+    model: opus
+  - phase: review
+    effort: high
+    model: opus
+---
+
+# Task: High-effort fixture
+
+## Intent
+
+Test fixture for v5.1.1 runtime resolver tests — all 4 phases at the
+high effort tier with explicit opus model overrides. Mirrors the
+production-grade premium-profile scenario.
+
+## Goal
+
+Resolver returns `{effort: 'high', model: 'opus'}` for each of the 4
+PHASE_SIGNAL_PHASES.
+
+## Success Criteria
+
+- Validator passes.
+- resolvePhaseSignal(fm, phase).effort === 'high' for all 4 phases.
+- resolvePhaseSignal(fm, phase).model === 'opus' for all 4 phases.
diff --git a/plugins/voyage/tests/fixtures/brief-effort-low.md b/plugins/voyage/tests/fixtures/brief-effort-low.md
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+---
+type: trekbrief
+brief_version: "2.1"
+created: 2026-05-14
+task: "Fixture: low-effort all phases (v5.1.1 runtime test)"
+slug: brief-effort-low
+project_dir: .claude/projects/2026-05-14-brief-effort-low/
+research_topics: 0
+research_status: complete
+auto_research: false
+interview_turns: 4
+source: fixture
+phase_signals:
+  - phase: research
+    effort: low
+    model: sonnet
+  - phase: plan
+    effort: low
+    model: sonnet
+  - phase: execute
+    effort: low
+    model: sonnet
+  - phase: review
+    effort: low
+    model: sonnet
+---
+
+# Task: Low-effort fixture
+
+## Intent
+
+Test fixture for v5.1.1 runtime resolver tests — all 4 phases at the lowest
+effort tier with explicit sonnet model overrides.
+
+## Goal
+
+Resolver returns `{effort: 'low', model: 'sonnet'}` for each of the 4
+PHASE_SIGNAL_PHASES.
+
+## Success Criteria
+
+- Validator passes.
+- resolvePhaseSignal(fm, phase) is non-null for all 4 phases.
diff --git a/plugins/voyage/tests/fixtures/brief-effort-standard.md b/plugins/voyage/tests/fixtures/brief-effort-standard.md
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+---
+type: trekbrief
+brief_version: "2.1"
+created: 2026-05-14
+task: "Fixture: standard-effort all phases, no model (v5.1.1 runtime test)"
+slug: brief-effort-standard
+project_dir: .claude/projects/2026-05-14-brief-effort-standard/
+research_topics: 0
+research_status: complete
+auto_research: false
+interview_turns: 4
+source: fixture
+phase_signals:
+  - phase: research
+    effort: standard
+  - phase: plan
+    effort: standard
+  - phase: execute
+    effort: standard
+  - phase: review
+    effort: standard
+---
+
+# Task: Standard-effort fixture (no model override)
+
+## Intent
+
+Test fixture for v5.1.1 runtime resolver tests — all 4 phases at the
+standard tier WITHOUT explicit model fields. This is the operator-skipped
+model path that should fall through to the profile.
+
+## Goal
+
+Resolver returns `{effort: 'standard', model: undefined}` for each of the 4
+PHASE_SIGNAL_PHASES. The orchestrator-model path then falls through to the
+active profile's phase_models.
+
+## Success Criteria
+
+- Validator passes.
+- resolvePhaseSignal(fm, phase).model is undefined.
+- resolvePhaseSignal(fm, phase).effort is 'standard'.
diff --git a/plugins/voyage/tests/fixtures/brief-v21-no-signals.md b/plugins/voyage/tests/fixtures/brief-v21-no-signals.md
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+---
+type: trekbrief
+brief_version: "2.1"
+created: 2026-05-14
+task: "Fixture: v5.1 brief WITHOUT phase_signals or partial (falsification target)"
+slug: brief-v21-no-signals
+project_dir: .claude/projects/2026-05-14-brief-v21-no-signals/
+research_topics: 0
+research_status: complete
+auto_research: false
+interview_turns: 4
+source: fixture
+---
+
+# Task: brief_version 2.1 without phase_signals
+
+## Intent
+
+Falsification fixture for the v5.1 sequencing gate. The brief declares
+`brief_version: "2.1"` but omits BOTH `phase_signals` AND
+`phase_signals_partial: true`. The brief-validator MUST emit
+`BRIEF_V51_MISSING_SIGNALS` for this file — the runtime test for the
+sequencing gate asserts the error code fires.
+
+## Goal
+
+Validate that brief-validator catches the missing-signals scenario.
+
+## Success Criteria
+
+- brief-validator returns valid: false.
+- errors contains BRIEF_V51_MISSING_SIGNALS.