diff --git a/packages/pi-ai/src/providers/anthropic.ts b/packages/pi-ai/src/providers/anthropic.ts
index 7a823e3d7..e4f49de58 100644
--- a/packages/pi-ai/src/providers/anthropic.ts
+++ b/packages/pi-ai/src/providers/anthropic.ts
@@ -637,8 +637,12 @@ function buildParams(
 	options?: AnthropicOptions,
 ): MessageCreateParamsStreaming {
 	const { cacheControl } = getCacheControl(model.baseUrl, options?.cacheRetention);
+	// For OAuth (Claude Max/Pro), strip variant suffixes like [1m] from model ID.
+	// The API only accepts the base model ID (e.g. "claude-opus-4-6"),
+	// not internal variant identifiers (e.g. "claude-opus-4-6[1m]").
+	const apiModelId = isOAuthToken ? model.id.replace(/\[.*\]$/, "") : model.id;
 	const params: MessageCreateParamsStreaming = {
-		model: model.id,
+		model: apiModelId,
 		messages: convertMessages(context.messages, model, isOAuthToken, cacheControl),
 		max_tokens: options?.maxTokens || (model.maxTokens / 3) | 0,
 		stream: true,
diff --git a/src/resources/extensions/gsd/auto.ts b/src/resources/extensions/gsd/auto.ts
index aadb740d5..f23e0fa36 100644
--- a/src/resources/extensions/gsd/auto.ts
+++ b/src/resources/extensions/gsd/auto.ts
@@ -3065,7 +3065,11 @@ export function verifyExpectedArtifact(unitType: string, unitId: string, base: s
     }
   }
 
-  // complete-slice must also produce a UAT file
+  // complete-slice must also produce a UAT file AND mark the slice [x] in the roadmap.
+  // Without the roadmap check, a crash after writing SUMMARY+UAT but before updating
+  // the roadmap causes an infinite skip loop: the idempotency key says "done" but the
+  // state machine keeps returning the same complete-slice unit (roadmap still shows
+  // the slice incomplete), so dispatchNextUnit recurses forever.
   if (unitType === "complete-slice") {
     const parts = unitId.split("/");
     const mid = parts[0];
@@ -3076,6 +3080,17 @@ export function verifyExpectedArtifact(unitType: string, unitId: string, base: s
         const uatPath = join(dir, buildSliceFileName(sid, "UAT"));
         if (!existsSync(uatPath)) return false;
       }
+      // Verify the roadmap has the slice marked [x]. If not, the completion
+      // record is stale — the unit must re-run to update the roadmap.
+      const roadmapFile = resolveMilestoneFile(base, mid, "ROADMAP");
+      if (roadmapFile && existsSync(roadmapFile)) {
+        try {
+          const roadmapContent = readFileSync(roadmapFile, "utf-8");
+          const roadmap = parseRoadmap(roadmapContent);
+          const slice = roadmap.slices.find(s => s.id === sid);
+          if (slice && !slice.done) return false;
+        } catch { /* corrupt roadmap — be lenient and treat as verified */ }
+      }
     }
   }
 
diff --git a/src/resources/extensions/gsd/tests/idle-recovery.test.ts b/src/resources/extensions/gsd/tests/idle-recovery.test.ts
index ef1492e01..4ca52330e 100644
--- a/src/resources/extensions/gsd/tests/idle-recovery.test.ts
+++ b/src/resources/extensions/gsd/tests/idle-recovery.test.ts
@@ -409,6 +409,87 @@ function createGitBase(): string {
   }
 }
 
+// ═══ verifyExpectedArtifact: complete-slice roadmap check ════════════════════
+// Regression for #indefinite-hang: complete-slice must verify roadmap [x] or
+// the idempotency skip loops forever after a crash that wrote SUMMARY+UAT but
+// did not mark the roadmap done.
+
+const ROADMAP_INCOMPLETE = `# M001: Test Milestone
+
+## Slices
+
+- [ ] **S01: Test Slice** \`risk:low\`
+> After this: something works
+`;
+
+const ROADMAP_COMPLETE = `# M001: Test Milestone
+
+## Slices
+
+- [x] **S01: Test Slice** \`risk:low\`
+> After this: something works
+`;
+
+{
+  console.log("\n=== verifyExpectedArtifact: complete-slice — all artifacts present + roadmap marked [x] returns true ===");
+  const base = createFixtureBase();
+  try {
+    const sliceDir = join(base, ".gsd", "milestones", "M001", "slices", "S01");
+    writeFileSync(join(sliceDir, "S01-SUMMARY.md"), "# Summary\n", "utf-8");
+    writeFileSync(join(sliceDir, "S01-UAT.md"), "# UAT\n", "utf-8");
+    writeFileSync(join(base, ".gsd", "milestones", "M001", "M001-ROADMAP.md"), ROADMAP_COMPLETE, "utf-8");
+    const result = verifyExpectedArtifact("complete-slice", "M001/S01", base);
+    assert(result === true, "SUMMARY + UAT + roadmap [x] should verify as true");
+  } finally {
+    cleanup(base);
+  }
+}
+
+{
+  console.log("\n=== verifyExpectedArtifact: complete-slice — SUMMARY + UAT present but roadmap NOT marked [x] returns false ===");
+  const base = createFixtureBase();
+  try {
+    const sliceDir = join(base, ".gsd", "milestones", "M001", "slices", "S01");
+    writeFileSync(join(sliceDir, "S01-SUMMARY.md"), "# Summary\n", "utf-8");
+    writeFileSync(join(sliceDir, "S01-UAT.md"), "# UAT\n", "utf-8");
+    writeFileSync(join(base, ".gsd", "milestones", "M001", "M001-ROADMAP.md"), ROADMAP_INCOMPLETE, "utf-8");
+    const result = verifyExpectedArtifact("complete-slice", "M001/S01", base);
+    assert(result === false, "roadmap not marked [x] should return false (crash recovery scenario)");
+  } finally {
+    cleanup(base);
+  }
+}
+
+{
+  console.log("\n=== verifyExpectedArtifact: complete-slice — SUMMARY present but UAT missing returns false ===");
+  const base = createFixtureBase();
+  try {
+    const sliceDir = join(base, ".gsd", "milestones", "M001", "slices", "S01");
+    writeFileSync(join(sliceDir, "S01-SUMMARY.md"), "# Summary\n", "utf-8");
+    // no UAT file
+    writeFileSync(join(base, ".gsd", "milestones", "M001", "M001-ROADMAP.md"), ROADMAP_COMPLETE, "utf-8");
+    const result = verifyExpectedArtifact("complete-slice", "M001/S01", base);
+    assert(result === false, "missing UAT should return false");
+  } finally {
+    cleanup(base);
+  }
+}
+
+{
+  console.log("\n=== verifyExpectedArtifact: complete-slice — no roadmap file present is lenient (returns true) ===");
+  const base = createFixtureBase();
+  try {
+    const sliceDir = join(base, ".gsd", "milestones", "M001", "slices", "S01");
+    writeFileSync(join(sliceDir, "S01-SUMMARY.md"), "# Summary\n", "utf-8");
+    writeFileSync(join(sliceDir, "S01-UAT.md"), "# UAT\n", "utf-8");
+    // no roadmap file
+    const result = verifyExpectedArtifact("complete-slice", "M001/S01", base);
+    assert(result === true, "missing roadmap file should be lenient and return true");
+  } finally {
+    cleanup(base);
+  }
+}
+
 // ═════════════════════════════════════════════════════════════════════════════
 // Results
 // ═════════════════════════════════════════════════════════════════════════════