diff --git a/packages/dashboard/app/components/AgentLogViewer.tsx b/packages/dashboard/app/components/AgentLogViewer.tsx
index 932ef682c..a1f1577de 100644
--- a/packages/dashboard/app/components/AgentLogViewer.tsx
+++ b/packages/dashboard/app/components/AgentLogViewer.tsx
@@ -268,10 +268,8 @@ export function AgentLogViewer({
 
   return (
     <div
-      ref={containerRef}
       className={`agent-log-viewer agent-log-viewer--streaming${isFullscreen ? " agent-log-viewer--fullscreen" : ""}`}
       data-testid="agent-log-viewer"
-      onScroll={handleScroll}
     >
       {/* Model info header */}
       <div className="agent-log-model-header" data-testid="agent-log-model-header">
@@ -357,66 +355,106 @@ export function AgentLogViewer({
         )}
       </div>
 
-      {/* Pagination summary */}
-      {totalCount !== null && (
-        <div className="agent-log-summary" data-testid="agent-log-summary">
-          Showing {entries.length} of {totalCount} entries
-        </div>
-      )}
+      <div
+        ref={containerRef}
+        className="agent-log-viewer-scroll"
+        onScroll={handleScroll}
+      >
+        {/* Pagination summary */}
+        {totalCount !== null && (
+          <div className="agent-log-summary" data-testid="agent-log-summary">
+            Showing {entries.length} of {totalCount} entries
+          </div>
+        )}
 
-      {hasMore && onLoadMore && (
-        <div className="agent-log-load-more" data-testid="agent-log-load-more">
-          <button
-            className="agent-log-mode-toggle"
-            onClick={onLoadMore}
-            disabled={loadingMore}
-            data-testid="agent-log-load-more-button"
-          >
-            {loadingMore ? (
-              <>
-                <Loader2 size={14} className="animate-spin" />
-                Loading…
-              </>
-            ) : (
-              "Load More"
-            )}
-          </button>
-        </div>
-      )}
+        {hasMore && onLoadMore && (
+          <div className="agent-log-load-more" data-testid="agent-log-load-more">
+            <button
+              className="agent-log-mode-toggle"
+              onClick={onLoadMore}
+              disabled={loadingMore}
+              data-testid="agent-log-load-more-button"
+            >
+              {loadingMore ? (
+                <>
+                  <Loader2 size={14} className="animate-spin" />
+                  Loading…
+                </>
+              ) : (
+                "Load More"
+              )}
+            </button>
+          </div>
+        )}
 
-      {entries.map((entry, i) => {
-        const rowKey = chronologicalEntryKeys[i] ?? `${getEntrySignature(entry)}|fallback`;
-        const prev = entries[i - 1];
-        const isBlockLevel = entry.type === "tool" || entry.type === "tool_result" || entry.type === "tool_error";
-        const showBadge = entry.agent
-          ? isBlockLevel || !prev || prev.agent !== entry.agent || prev.type !== entry.type
-          : false;
+        {entries.map((entry, i) => {
+          const rowKey = chronologicalEntryKeys[i] ?? `${getEntrySignature(entry)}|fallback`;
+          const prev = entries[i - 1];
+          const isBlockLevel = entry.type === "tool" || entry.type === "tool_result" || entry.type === "tool_error";
+          const showBadge = entry.agent
+            ? isBlockLevel || !prev || prev.agent !== entry.agent || prev.type !== entry.type
+            : false;
 
-        const timestampSpan = showBadge ? (
-          <span className="agent-log-timestamp" data-testid="agent-log-timestamp">
-            {formatTimestamp(entry.timestamp)}
-          </span>
-        ) : null;
+          const timestampSpan = showBadge ? (
+            <span className="agent-log-timestamp" data-testid="agent-log-timestamp">
+              {formatTimestamp(entry.timestamp)}
+            </span>
+          ) : null;
 
-        const agentBadge = showBadge ? (
-          <span className="agent-log-badge-row">
-            <span className="agent-log-agent-badge">[{entry.agent}]</span>
-            {timestampSpan}
-          </span>
-        ) : null;
+          const agentBadge = showBadge ? (
+            <span className="agent-log-badge-row">
+              <span className="agent-log-agent-badge">[{entry.agent}]</span>
+              {timestampSpan}
+            </span>
+          ) : null;
 
-        if (entry.type === "tool") {
+          if (entry.type === "tool") {
+            return (
+              <div key={rowKey} className="agent-log-tool">
+                {agentBadge}⚡ {entry.text}
+                {entry.detail && <span className="agent-log-tool-detail">— {entry.detail}</span>}
+              </div>
+            );
+          }
+
+          if (entry.type === "thinking") {
+            return (
+              <div key={rowKey} className="agent-log-thinking">
+                {agentBadge}
+                {renderMarkdown ? (
+                  <div className="markdown-body">
+                    <ReactMarkdown remarkPlugins={[remarkGfm]} components={markdownComponents}>
+                      {entry.text}
+                    </ReactMarkdown>
+                  </div>
+                ) : (
+                  entry.text
+                )}
+              </div>
+            );
+          }
+
+          if (entry.type === "tool_result") {
+            return (
+              <div key={rowKey} className="agent-log-tool-result">
+                {agentBadge}✓ {entry.text}
+                {entry.detail && <span className="agent-log-tool-detail">— {entry.detail}</span>}
+              </div>
+            );
+          }
+
+          if (entry.type === "tool_error") {
+            return (
+              <div key={rowKey} className="agent-log-tool-error">
+                {agentBadge}✗ {entry.text}
+                {entry.detail && <span className="agent-log-tool-detail">— {entry.detail}</span>}
+              </div>
+            );
+          }
+
+          // Default: text entries
           return (
-            <div key={rowKey} className="agent-log-tool">
-              {agentBadge}⚡ {entry.text}
-              {entry.detail && <span className="agent-log-tool-detail">— {entry.detail}</span>}
-            </div>
-          );
-        }
-
-        if (entry.type === "thinking") {
-          return (
-            <div key={rowKey} className="agent-log-thinking">
+            <div key={rowKey} className="agent-log-text">
               {agentBadge}
               {renderMarkdown ? (
                 <div className="markdown-body">
@@ -429,54 +467,20 @@ export function AgentLogViewer({
               )}
             </div>
           );
-        }
+        })}
 
-        if (entry.type === "tool_result") {
-          return (
-            <div key={rowKey} className="agent-log-tool-result">
-              {agentBadge}✓ {entry.text}
-              {entry.detail && <span className="agent-log-tool-detail">— {entry.detail}</span>}
-            </div>
-          );
-        }
-
-        if (entry.type === "tool_error") {
-          return (
-            <div key={rowKey} className="agent-log-tool-error">
-              {agentBadge}✗ {entry.text}
-              {entry.detail && <span className="agent-log-tool-detail">— {entry.detail}</span>}
-            </div>
-          );
-        }
-
-        // Default: text entries
-        return (
-          <div key={rowKey} className="agent-log-text">
-            {agentBadge}
-            {renderMarkdown ? (
-              <div className="markdown-body">
-                <ReactMarkdown remarkPlugins={[remarkGfm]} components={markdownComponents}>
-                  {entry.text}
-                </ReactMarkdown>
-              </div>
-            ) : (
-              entry.text
-            )}
-          </div>
-        );
-      })}
-
-      {!isFollowing && (
-        <button
-          type="button"
-          className="agent-log-return-to-live"
-          onClick={scrollToLive}
-          data-testid="agent-log-return-to-live"
-        >
-          <ChevronDown size={12} />
-          <span>Live</span>
-        </button>
-      )}
+        {!isFollowing && (
+          <button
+            type="button"
+            className="agent-log-return-to-live"
+            onClick={scrollToLive}
+            data-testid="agent-log-return-to-live"
+          >
+            <ChevronDown size={12} />
+            <span>Live</span>
+          </button>
+        )}
+      </div>
     </div>
   );
 }
diff --git a/packages/dashboard/app/components/TaskDetailModal.css b/packages/dashboard/app/components/TaskDetailModal.css
index d990ca935..8d82b38d2 100644
--- a/packages/dashboard/app/components/TaskDetailModal.css
+++ b/packages/dashboard/app/components/TaskDetailModal.css
@@ -232,6 +232,16 @@
 }
 
 .detail-section--agent-log .agent-log-viewer {
+  display: flex;
+  flex-direction: column;
+  flex: 1;
+  min-height: 0;
+  background: var(--bg-secondary);
+  border-radius: var(--radius-sm);
+  overflow: hidden;
+}
+
+.agent-log-viewer-scroll {
   flex: 1;
   min-height: 0;
   overflow-y: auto;
@@ -241,8 +251,6 @@
   line-height: 1.5;
   color: var(--text);
   padding: var(--space-md);
-  background: var(--bg-secondary);
-  border-radius: var(--radius-sm);
   white-space: pre-wrap;
   word-break: break-word;
   overflow-wrap: break-word;
@@ -474,20 +482,23 @@
   position: fixed;
   inset: 0;
   z-index: 10000;
+  display: flex;
+  flex-direction: column;
+  min-height: 0;
   background: var(--surface);
-  overflow-y: auto;
-  overflow-x: hidden;
   padding: var(--space-lg);
 }
 
 .agent-log-viewer--fullscreen .agent-log-model-header {
-  position: sticky;
-  top: 0;
+  margin-bottom: 0;
   background: var(--surface);
-  z-index: 1;
-  padding-bottom: var(--space-md);
-  margin-bottom: var(--space-md);
-  border-bottom: 1px solid var(--border);
+  border: 1px solid var(--border);
+}
+
+.agent-log-viewer--fullscreen .agent-log-viewer-scroll {
+  flex: 1;
+  min-height: 0;
+  overflow-y: auto;
 }
 
 .detail-spec-edit-trigger {
diff --git a/packages/dashboard/app/components/__tests__/AgentLogViewer.test.tsx b/packages/dashboard/app/components/__tests__/AgentLogViewer.test.tsx
index c5999fa5e..d23f52b9a 100644
--- a/packages/dashboard/app/components/__tests__/AgentLogViewer.test.tsx
+++ b/packages/dashboard/app/components/__tests__/AgentLogViewer.test.tsx
@@ -25,6 +25,10 @@ function makeEntry(overrides: Partial<AgentLogEntry> = {}): AgentLogEntry {
   };
 }
 
+function getScrollContainer(container: HTMLElement): HTMLDivElement {
+  return container.querySelector(".agent-log-viewer-scroll") as HTMLDivElement;
+}
+
 describe("AgentLogViewer", () => {
   it("shows loading message when loading with no entries", () => {
     render(<AgentLogViewer entries={[]} loading={true} />);
@@ -736,21 +740,21 @@ describe("AgentLogViewer", () => {
   });
 
   describe("horizontal overflow prevention", () => {
-    it("uses the viewer class for overflow-x handling", () => {
+    it("uses the scroll container class for overflow-x handling", () => {
       const longString = "A".repeat(300);
       const entries = [makeEntry({ text: longString })];
       const { container } = render(<AgentLogViewer entries={entries} loading={false} />);
-      const viewer = container.querySelector("[data-testid='agent-log-viewer']") as HTMLElement;
-      expect(viewer.classList.contains("agent-log-viewer")).toBe(true);
-      expect(viewer.style.overflowX).toBe("");
+      const scrollContainer = getScrollContainer(container);
+      expect(scrollContainer.classList.contains("agent-log-viewer-scroll")).toBe(true);
+      expect(scrollContainer.style.overflowX).toBe("");
     });
 
-    it("uses the viewer class for overflow-wrap handling", () => {
+    it("uses the scroll container class for overflow-wrap handling", () => {
       const entries = [makeEntry({ text: "x".repeat(250) })];
       const { container } = render(<AgentLogViewer entries={entries} loading={false} />);
-      const viewer = container.querySelector("[data-testid='agent-log-viewer']") as HTMLElement;
-      expect(viewer.classList.contains("agent-log-viewer")).toBe(true);
-      expect(viewer.style.overflowWrap).toBe("");
+      const scrollContainer = getScrollContainer(container);
+      expect(scrollContainer.classList.contains("agent-log-viewer-scroll")).toBe(true);
+      expect(scrollContainer.style.overflowWrap).toBe("");
     });
 
     it("renders pre elements with overflow-x auto for internal scrolling", () => {
@@ -783,13 +787,13 @@ describe("AgentLogViewer", () => {
       expect(viewer.style.maxHeight).toBe("");
     });
 
-    it("uses class-based overflow-y scrolling", () => {
+    it("uses class-based overflow-y scrolling on the entries container", () => {
       const entries = [makeEntry()];
       const { container } = render(<AgentLogViewer entries={entries} loading={false} />);
-      const viewer = container.querySelector("[data-testid='agent-log-viewer']") as HTMLElement;
+      const scrollContainer = getScrollContainer(container);
       // Scrolling behavior is now defined in CSS.
-      expect(viewer.classList.contains("agent-log-viewer")).toBe(true);
-      expect(viewer.style.overflowY).toBe("");
+      expect(scrollContainer.classList.contains("agent-log-viewer-scroll")).toBe(true);
+      expect(scrollContainer.style.overflowY).toBe("");
     });
 
     it("uses agent-log-viewer--streaming class when entries are present", () => {
@@ -808,6 +812,67 @@ describe("AgentLogViewer", () => {
     });
   });
 
+  describe("sticky header layout", () => {
+    it("renders the model header as a sibling of the scroll container", () => {
+      const entries = [makeEntry()];
+      const { container } = render(<AgentLogViewer entries={entries} loading={false} />);
+      const viewer = container.querySelector("[data-testid='agent-log-viewer']") as HTMLElement;
+      const header = screen.getByTestId("agent-log-model-header");
+      const scrollContainer = getScrollContainer(container);
+
+      expect(header.parentElement).toBe(viewer);
+      expect(scrollContainer.parentElement).toBe(viewer);
+      expect(scrollContainer.contains(header)).toBe(false);
+    });
+
+    it("renders log entry rows inside the scroll container", () => {
+      const entries = [
+        makeEntry({ type: "text", text: "hello" }),
+        makeEntry({ type: "tool", text: "Bash" }),
+      ];
+      const { container } = render(<AgentLogViewer entries={entries} loading={false} />);
+      const scrollContainer = getScrollContainer(container);
+
+      expect(scrollContainer.querySelector(".agent-log-text")).toBeTruthy();
+      expect(scrollContainer.querySelector(".agent-log-tool")).toBeTruthy();
+    });
+
+    it("renders pagination summary and load-more controls inside the scroll container", () => {
+      const entries = [makeEntry({ text: "hello" })];
+      const { container } = render(
+        <AgentLogViewer
+          entries={entries}
+          loading={false}
+          totalCount={42}
+          hasMore={true}
+          onLoadMore={() => {}}
+        />,
+      );
+      const scrollContainer = getScrollContainer(container);
+
+      expect(scrollContainer.querySelector("[data-testid='agent-log-summary']")).toBeTruthy();
+      expect(scrollContainer.querySelector("[data-testid='agent-log-load-more']")).toBeTruthy();
+    });
+
+    it("renders the return-to-live button inside the scroll container", () => {
+      const entries = [
+        makeEntry({ text: "first", timestamp: "2026-01-01T00:00:00Z" }),
+        makeEntry({ text: "second", timestamp: "2026-01-01T00:00:01Z" }),
+      ];
+      const { container } = render(<AgentLogViewer entries={entries} loading={false} />);
+      const scrollContainer = getScrollContainer(container);
+
+      Object.defineProperty(scrollContainer, "scrollHeight", { configurable: true, value: 1000 });
+      Object.defineProperty(scrollContainer, "clientHeight", { configurable: true, value: 200 });
+
+      scrollContainer.scrollTop = 300;
+      fireEvent.scroll(scrollContainer);
+
+      const returnToLive = screen.getByTestId("agent-log-return-to-live");
+      expect(returnToLive.parentElement).toBe(scrollContainer);
+    });
+  });
+
   describe("auto-scroll behavior", () => {
     it("scrolls to bottom when streaming updates arrive and user is near the bottom", () => {
       const initialEntries = [
@@ -819,7 +884,7 @@ describe("AgentLogViewer", () => {
       ];
 
       const { rerender, container } = render(<AgentLogViewer entries={initialEntries} loading={false} />);
-      const viewer = container.querySelector("[data-testid='agent-log-viewer']") as HTMLDivElement;
+      const viewer = getScrollContainer(container);
 
       let scrollHeight = 600;
       Object.defineProperty(viewer, "scrollHeight", {
@@ -846,7 +911,7 @@ describe("AgentLogViewer", () => {
       ];
 
       const { rerender, container } = render(<AgentLogViewer entries={initialEntries} loading={false} />);
-      const viewer = container.querySelector("[data-testid='agent-log-viewer']") as HTMLDivElement;
+      const viewer = getScrollContainer(container);
 
       let scrollHeight = 1000;
       Object.defineProperty(viewer, "scrollHeight", {
@@ -873,7 +938,7 @@ describe("AgentLogViewer", () => {
       ];
 
       const { rerender, container } = render(<AgentLogViewer entries={initialEntries} loading={false} />);
-      const viewer = container.querySelector("[data-testid='agent-log-viewer']") as HTMLDivElement;
+      const viewer = getScrollContainer(container);
 
       let scrollHeight = 900;
       Object.defineProperty(viewer, "scrollHeight", {
@@ -897,7 +962,7 @@ describe("AgentLogViewer", () => {
         makeEntry({ text: "second", timestamp: "2026-01-01T00:00:01Z" }),
       ];
       const { container } = render(<AgentLogViewer entries={entries} loading={false} />);
-      const viewer = container.querySelector("[data-testid='agent-log-viewer']") as HTMLDivElement;
+      const viewer = getScrollContainer(container);
 
       Object.defineProperty(viewer, "scrollHeight", { configurable: true, value: 1000 });
       Object.defineProperty(viewer, "clientHeight", { configurable: true, value: 200 });
@@ -914,7 +979,7 @@ describe("AgentLogViewer", () => {
         makeEntry({ text: "second", timestamp: "2026-01-01T00:00:01Z" }),
       ];
       const { container } = render(<AgentLogViewer entries={entries} loading={false} />);
-      const viewer = container.querySelector("[data-testid='agent-log-viewer']") as HTMLDivElement;
+      const viewer = getScrollContainer(container);
 
       Object.defineProperty(viewer, "scrollHeight", { configurable: true, value: 1000 });
       Object.defineProperty(viewer, "clientHeight", { configurable: true, value: 200 });
@@ -931,7 +996,7 @@ describe("AgentLogViewer", () => {
         makeEntry({ text: "second", timestamp: "2026-01-01T00:00:01Z" }),
       ];
       const { container } = render(<AgentLogViewer entries={entries} loading={false} />);
-      const viewer = container.querySelector("[data-testid='agent-log-viewer']") as HTMLDivElement;
+      const viewer = getScrollContainer(container);
 
       Object.defineProperty(viewer, "scrollHeight", { configurable: true, value: 1000 });
       Object.defineProperty(viewer, "clientHeight", { configurable: true, value: 200 });