diff --git a/sdk/src/query/phase-lifecycle.test.ts b/sdk/src/query/phase-lifecycle.test.ts
index 9a4a0200d..256e7cc2f 100644
--- a/sdk/src/query/phase-lifecycle.test.ts
+++ b/sdk/src/query/phase-lifecycle.test.ts
@@ -245,6 +245,77 @@ describe('phaseAdd', () => {
     expect(phaseIdx).toBeLessThan(sepIdx);
     expect(phaseIdx).toBeGreaterThan(0);
   });
+
+  it('detects max phase from bullet checklist format (regression #2726)', async () => {
+    const { phaseAdd } = await import('./phase-lifecycle.js');
+
+    const roadmap = [
+      '# Roadmap',
+      '',
+      '## Current Milestone: v5.0',
+      '',
+      '- [x] Phase 76: Data Import',
+      '- [x] Phase 77: Data Transform',
+      '- [ ] Phase 88: Final Cleanup',
+      '',
+    ].join('\n');
+
+    await setupTestProject(tmpDir, {
+      roadmap,
+      state: MINIMAL_STATE,
+      phases: [],
+    });
+
+    const result = await phaseAdd(['new-feature'], tmpDir);
+    const data = result.data as Record<string, unknown>;
+
+    expect(data.phase_number).toBe(89);
+    expect(data.padded).toBe('89');
+  });
+
+  it('detects max phase from bold inline format (regression #2726)', async () => {
+    const { phaseAdd } = await import('./phase-lifecycle.js');
+
+    const roadmap = [
+      '# Roadmap',
+      '',
+      '## Current Milestone: v5.0',
+      '',
+      '**Phase 50: Core Infrastructure**',
+      '**Phase 51: API Layer**',
+      '',
+    ].join('\n');
+
+    await setupTestProject(tmpDir, {
+      roadmap,
+      state: MINIMAL_STATE,
+      phases: [],
+    });
+
+    const result = await phaseAdd(['new-feature'], tmpDir);
+    const data = result.data as Record<string, unknown>;
+
+    expect(data.phase_number).toBe(52);
+  });
+
+  it('falls back to filesystem scan when no phase matches in ROADMAP (regression #2726)', async () => {
+    const { phaseAdd } = await import('./phase-lifecycle.js');
+
+    // ROADMAP with no recognizable phase entries
+    const roadmap = '# Roadmap\n\n## Current Milestone: v5.0\n\nSome content without phases\n';
+
+    await setupTestProject(tmpDir, {
+      roadmap,
+      state: MINIMAL_STATE,
+      phases: ['45-legacy-phase', '46-another-phase'],
+    });
+
+    const result = await phaseAdd(['new-feature'], tmpDir);
+    const data = result.data as Record<string, unknown>;
+
+    // Should detect phases 45 and 46 on disk, so new phase = 47
+    expect(data.phase_number).toBe(47);
+  });
 });
 
 // ─── phaseAddBatch ─────────────────────────────────────────────────────
diff --git a/sdk/src/query/phase-lifecycle.ts b/sdk/src/query/phase-lifecycle.ts
index 5211c46a6..f3b4f4236 100644
--- a/sdk/src/query/phase-lifecycle.ts
+++ b/sdk/src/query/phase-lifecycle.ts
@@ -191,7 +191,8 @@ export const phaseAdd: QueryHandler = async (args, projectDir, workstream) => {
     } else {
       // Sequential mode: find highest integer phase number (in current milestone only)
       // Skip 999.x backlog phases — they live outside the active sequence
-      const phasePattern = /#{2,4}\s*Phase\s+(\d+)[A-Z]?(?:\.\d+)*:/gi;
+      // Matches heading (## Phase N:), bullet checklist (- [x] Phase N:), and bold (**Phase N:**)
+      const phasePattern = /(?:^|\n)\s*(?:[-*]\s*(?:\[[x ]\]\s*)?|#{2,4}\s*|\*{1,2}\s*)Phase\s+(\d+)[A-Z]?(?:\.\d+)*:/gi;
       let maxPhase = 0;
       let m: RegExpExecArray | null;
       while ((m = phasePattern.exec(content)) !== null) {
@@ -200,6 +201,26 @@ export const phaseAdd: QueryHandler = async (args, projectDir, workstream) => {
         if (num > maxPhase) maxPhase = num;
       }
 
+      // Belt-and-suspenders: if ROADMAP scan found nothing, fall back to scanning
+      // .planning/phases/ directory names as the canonical source of truth
+      if (maxPhase === 0) {
+        const phasesDir = planningPaths(projectDir, workstream).phases;
+        try {
+          const entries = await readdir(phasesDir, { withFileTypes: true });
+          for (const entry of entries) {
+            if (!entry.isDirectory()) continue;
+            const dirMatch = /^(\d+)[A-Z]?(?:\.\d+)*-/.exec(entry.name);
+            if (dirMatch) {
+              const num = parseInt(dirMatch[1], 10);
+              if (num >= 999) continue;
+              if (num > maxPhase) maxPhase = num;
+            }
+          }
+        } catch {
+          // phases dir may not exist yet — leave maxPhase as 0
+        }
+      }
+
       newPhaseId = maxPhase + 1;
       const paddedNum = String(newPhaseId).padStart(2, '0');
       dirName = `${prefix}${paddedNum}-${slug}`;