diff --git a/src/features/messages/components/Markdown.test.tsx b/src/features/messages/components/Markdown.test.tsx
new file mode 100644
index 000000000..b96f29419
--- /dev/null
+++ b/src/features/messages/components/Markdown.test.tsx
@@ -0,0 +1,72 @@
+// @vitest-environment jsdom
+import { cleanup, createEvent, fireEvent, render, screen } from "@testing-library/react";
+import { afterEach, describe, expect, it, vi } from "vitest";
+import { Markdown } from "./Markdown";
+
+describe("Markdown file-like href behavior", () => {
+  afterEach(() => {
+    cleanup();
+  });
+
+  it("preserves default anchor navigation when no file opener is provided", () => {
+    render(
+      <Markdown
+        value="See [setup](./docs/setup.md)"
+        className="markdown"
+      />,
+    );
+
+    const link = screen.getByText("setup").closest("a");
+    expect(link?.getAttribute("href")).toBe("./docs/setup.md");
+
+    const clickEvent = createEvent.click(link as Element, {
+      bubbles: true,
+      cancelable: true,
+    });
+    fireEvent(link as Element, clickEvent);
+    expect(clickEvent.defaultPrevented).toBe(false);
+  });
+
+  it("intercepts file-like href clicks when a file opener is provided", () => {
+    const onOpenFileLink = vi.fn();
+    render(
+      <Markdown
+        value="See [setup](./docs/setup.md)"
+        className="markdown"
+        onOpenFileLink={onOpenFileLink}
+      />,
+    );
+
+    const link = screen.getByText("setup").closest("a");
+    expect(link?.getAttribute("href")).toBe("./docs/setup.md");
+
+    const clickEvent = createEvent.click(link as Element, {
+      bubbles: true,
+      cancelable: true,
+    });
+    fireEvent(link as Element, clickEvent);
+    expect(clickEvent.defaultPrevented).toBe(true);
+    expect(onOpenFileLink).toHaveBeenCalledWith("./docs/setup.md");
+  });
+
+  it("does not intercept bare relative links even when a file opener is provided", () => {
+    const onOpenFileLink = vi.fn();
+    render(
+      <Markdown
+        value="See [setup](docs/setup.md)"
+        className="markdown"
+        onOpenFileLink={onOpenFileLink}
+      />,
+    );
+
+    const link = screen.getByText("setup").closest("a");
+    expect(link?.getAttribute("href")).toBe("docs/setup.md");
+    const clickEvent = createEvent.click(link as Element, {
+      bubbles: true,
+      cancelable: true,
+    });
+    fireEvent(link as Element, clickEvent);
+    expect(clickEvent.defaultPrevented).toBe(false);
+    expect(onOpenFileLink).not.toHaveBeenCalled();
+  });
+});
diff --git a/src/features/messages/components/Markdown.tsx b/src/features/messages/components/Markdown.tsx
index ec450531d..91bb49e15 100644
--- a/src/features/messages/components/Markdown.tsx
+++ b/src/features/messages/components/Markdown.tsx
@@ -180,6 +180,151 @@ function normalizeUrlLine(line: string) {
   return withoutBullet;
 }
 
+function safeDecodeURIComponent(value: string) {
+  try {
+    return decodeURIComponent(value);
+  } catch {
+    return null;
+  }
+}
+
+function safeDecodeFileLink(url: string) {
+  try {
+    return decodeFileLink(url);
+  } catch {
+    return null;
+  }
+}
+
+const FILE_LINE_SUFFIX_PATTERN = /:\d+(?::\d+)?$/;
+const LIKELY_LOCAL_ABSOLUTE_PATH_PREFIXES = [
+  "/Users/",
+  "/home/",
+  "/tmp/",
+  "/var/",
+  "/opt/",
+  "/etc/",
+  "/private/",
+  "/Volumes/",
+  "/mnt/",
+  "/usr/",
+  "/workspace/",
+  "/workspaces/",
+  "/root/",
+  "/srv/",
+  "/data/",
+];
+
+function stripPathLineSuffix(value: string) {
+  return value.replace(FILE_LINE_SUFFIX_PATTERN, "");
+}
+
+function hasLikelyFileName(path: string) {
+  const normalizedPath = stripPathLineSuffix(path).replace(/[\\/]+$/, "");
+  const lastSegment = normalizedPath.split(/[\\/]/).pop() ?? "";
+  if (!lastSegment || lastSegment === "." || lastSegment === "..") {
+    return false;
+  }
+  if (lastSegment.startsWith(".") && lastSegment.length > 1) {
+    return true;
+  }
+  return lastSegment.includes(".");
+}
+
+function hasLikelyLocalAbsolutePrefix(path: string) {
+  const normalizedPath = path.replace(/\\/g, "/");
+  return LIKELY_LOCAL_ABSOLUTE_PATH_PREFIXES.some((prefix) =>
+    normalizedPath.startsWith(prefix),
+  );
+}
+
+function pathSegmentCount(path: string) {
+  return path.split("/").filter(Boolean).length;
+}
+
+function isLikelyFileHref(url: string) {
+  const trimmed = url.trim();
+  if (!trimmed) {
+    return false;
+  }
+  if (trimmed.startsWith("file://")) {
+    return true;
+  }
+  if (
+    trimmed.startsWith("http://") ||
+    trimmed.startsWith("https://") ||
+    trimmed.startsWith("mailto:")
+  ) {
+    return false;
+  }
+  if (trimmed.startsWith("thread://") || trimmed.startsWith("/thread/")) {
+    return false;
+  }
+  if (trimmed.startsWith("#")) {
+    return false;
+  }
+  if (/[?#]/.test(trimmed)) {
+    return false;
+  }
+  if (/^[A-Za-z]:[\\/]/.test(trimmed) || trimmed.startsWith("\\\\")) {
+    return true;
+  }
+  if (trimmed.startsWith("/")) {
+    if (FILE_LINE_SUFFIX_PATTERN.test(trimmed)) {
+      return true;
+    }
+    if (hasLikelyFileName(trimmed)) {
+      return true;
+    }
+    return hasLikelyLocalAbsolutePrefix(trimmed) && pathSegmentCount(trimmed) >= 3;
+  }
+  if (FILE_LINE_SUFFIX_PATTERN.test(trimmed)) {
+    return true;
+  }
+  if (trimmed.startsWith("~/")) {
+    return true;
+  }
+  if (trimmed.startsWith("./") || trimmed.startsWith("../")) {
+    return FILE_LINE_SUFFIX_PATTERN.test(trimmed) || hasLikelyFileName(trimmed);
+  }
+  if (hasLikelyFileName(trimmed)) {
+    return pathSegmentCount(trimmed) >= 3;
+  }
+  return false;
+}
+
+function toPathFromFileUrl(url: string) {
+  if (!url.toLowerCase().startsWith("file://")) {
+    return null;
+  }
+
+  try {
+    const parsed = new URL(url);
+    if (parsed.protocol !== "file:") {
+      return null;
+    }
+
+    const decodedPath = safeDecodeURIComponent(parsed.pathname) ?? parsed.pathname;
+    let path = decodedPath;
+    if (parsed.host && parsed.host !== "localhost") {
+      const normalizedPath = decodedPath.startsWith("/")
+        ? decodedPath
+        : `/${decodedPath}`;
+      path = `//${parsed.host}${normalizedPath}`;
+    }
+    if (/^\/[A-Za-z]:\//.test(path)) {
+      path = path.slice(1);
+    }
+    return path;
+  } catch {
+    const manualPath = url.slice("file://".length).trim();
+    if (!manualPath) {
+      return null;
+    }
+    return safeDecodeURIComponent(manualPath) ?? manualPath;
+  }
+}
+
 function extractUrlLines(value: string) {
   const lines = value.split(/\r?\n/);
   const urls = lines
@@ -474,9 +619,29 @@ export function Markdown({
     }
     return trimmed;
   };
+  const resolveHrefFilePath = (url: string) => {
+    if (isLikelyFileHref(url)) {
+      const directPath = getLinkablePath(url);
+      if (directPath) {
+        return safeDecodeURIComponent(directPath) ?? directPath;
+      }
+    }
+    const decodedUrl = safeDecodeURIComponent(url);
+    if (decodedUrl && isLikelyFileHref(decodedUrl)) {
+      const decodedPath = getLinkablePath(decodedUrl);
+      if (decodedPath) {
+        return decodedPath;
+      }
+    }
+    const fileUrlPath = toPathFromFileUrl(url);
+    if (!fileUrlPath) {
+      return null;
+    }
+    return getLinkablePath(fileUrlPath);
+  };
   const components: Components = {
     a: ({ href, children }) => {
-      const url = href ?? "";
+      const url = (href ?? "").trim();
       const threadId = url.startsWith("thread://")
         ? url.slice("thread://".length).trim()
         : url.startsWith("/thread/")
@@ -497,7 +662,20 @@ export function Markdown({
         );
       }
       if (isFileLinkUrl(url)) {
-        const path = decodeFileLink(url);
+        const path = safeDecodeFileLink(url);
+        if (!path) {
+          return (
+            <a
+              href={href}
+              onClick={(event) => {
+                event.preventDefault();
+                event.stopPropagation();
+              }}
+            >
+              {children}
+            </a>
+          );
+        }
         return (
           <FileReferenceLink
             href={href ?? toFileLink(path)}
@@ -509,6 +687,24 @@ export function Markdown({
           />
         );
       }
+      const hrefFilePath = resolveHrefFilePath(url);
+      if (hrefFilePath) {
+        const clickHandler = onOpenFileLink
+          ? (event: React.MouseEvent) => handleFileLinkClick(event, hrefFilePath)
+          : undefined;
+        const contextMenuHandler = onOpenFileLinkMenu
+          ? (event: React.MouseEvent) => handleFileLinkContextMenu(event, hrefFilePath)
+          : undefined;
+        return (
+          <a
+            href={href ?? toFileLink(hrefFilePath)}
+            onClick={clickHandler}
+            onContextMenu={contextMenuHandler}
+          >
+            {children}
+          </a>
+        );
+      }
       const isExternal =
         url.startsWith("http://") ||
         url.startsWith("https://") ||
diff --git a/src/features/messages/components/Messages.test.tsx b/src/features/messages/components/Messages.test.tsx
index efd3990d2..14cd95398 100644
--- a/src/features/messages/components/Messages.test.tsx
+++ b/src/features/messages/components/Messages.test.tsx
@@ -234,6 +234,190 @@ describe("Messages", () => {
     );
   });
 
+  it("routes markdown href file paths through the file opener", () => {
+    const linkedPath =
+      "/Users/dimillian/Documents/Dev/CodexMonitor/src/features/messages/components/Markdown.tsx:244";
+    const items: ConversationItem[] = [
+      {
+        id: "msg-file-href-link",
+        kind: "message",
+        role: "assistant",
+        text: `Open [this file](${linkedPath})`,
+      },
+    ];
+
+    render(
+      <Messages
+        items={items}
+        threadId="thread-1"
+        workspaceId="ws-1"
+        isThinking={false}
+        openTargets={[]}
+        selectedOpenAppId=""
+      />,
+    );
+
+    fireEvent.click(screen.getByText("this file"));
+    expect(openFileLinkMock).toHaveBeenCalledWith(linkedPath);
+  });
+
+  it("routes absolute non-whitelisted file href paths through the file opener", () => {
+    const linkedPath = "/custom/project/src/App.tsx:12";
+    const items: ConversationItem[] = [
+      {
+        id: "msg-file-href-absolute-non-whitelisted-link",
+        kind: "message",
+        role: "assistant",
+        text: `Open [app file](${linkedPath})`,
+      },
+    ];
+
+    render(
+      <Messages
+        items={items}
+        threadId="thread-1"
+        workspaceId="ws-1"
+        isThinking={false}
+        openTargets={[]}
+        selectedOpenAppId=""
+      />,
+    );
+
+    fireEvent.click(screen.getByText("app file"));
+    expect(openFileLinkMock).toHaveBeenCalledWith(linkedPath);
+  });
+
+  it("decodes percent-encoded href file paths before opening", () => {
+    const items: ConversationItem[] = [
+      {
+        id: "msg-file-href-encoded-link",
+        kind: "message",
+        role: "assistant",
+        text: "Open [guide](./docs/My%20Guide.md)",
+      },
+    ];
+
+    render(
+      <Messages
+        items={items}
+        threadId="thread-1"
+        workspaceId="ws-1"
+        isThinking={false}
+        openTargets={[]}
+        selectedOpenAppId=""
+      />,
+    );
+
+    fireEvent.click(screen.getByText("guide"));
+    expect(openFileLinkMock).toHaveBeenCalledWith("./docs/My Guide.md");
+  });
+
+  it("keeps non-file relative links as normal markdown links", () => {
+    const items: ConversationItem[] = [
+      {
+        id: "msg-help-href-link",
+        kind: "message",
+        role: "assistant",
+        text: "See [Help](/help/getting-started)",
+      },
+    ];
+
+    render(
+      <Messages
+        items={items}
+        threadId="thread-1"
+        workspaceId="ws-1"
+        isThinking={false}
+        openTargets={[]}
+        selectedOpenAppId=""
+      />,
+    );
+
+    const helpLink = screen.getByText("Help").closest("a");
+    expect(helpLink?.getAttribute("href")).toBe("/help/getting-started");
+    fireEvent.click(screen.getByText("Help"));
+    expect(openFileLinkMock).not.toHaveBeenCalled();
+  });
+
+  it("keeps route-like absolute links as normal markdown links", () => {
+    const items: ConversationItem[] = [
+      {
+        id: "msg-help-workspace-route-link",
+        kind: "message",
+        role: "assistant",
+        text: "See [Workspace Home](/workspace/settings)",
+      },
+    ];
+
+    render(
+      <Messages
+        items={items}
+        threadId="thread-1"
+        workspaceId="ws-1"
+        isThinking={false}
+        openTargets={[]}
+        selectedOpenAppId=""
+      />,
+    );
+
+    const link = screen.getByText("Workspace Home").closest("a");
+    expect(link?.getAttribute("href")).toBe("/workspace/settings");
+    fireEvent.click(screen.getByText("Workspace Home"));
+    expect(openFileLinkMock).not.toHaveBeenCalled();
+  });
+
+  it("keeps dot-relative non-file links as normal markdown links", () => {
+    const items: ConversationItem[] = [
+      {
+        id: "msg-help-dot-relative-href-link",
+        kind: "message",
+        role: "assistant",
+        text: "See [Help](./help/getting-started)",
+      },
+    ];
+
+    render(
+      <Messages
+        items={items}
+        threadId="thread-1"
+        workspaceId="ws-1"
+        isThinking={false}
+        openTargets={[]}
+        selectedOpenAppId=""
+      />,
+    );
+
+    const helpLink = screen.getByText("Help").closest("a");
+    expect(helpLink?.getAttribute("href")).toBe("./help/getting-started");
+    fireEvent.click(screen.getByText("Help"));
+    expect(openFileLinkMock).not.toHaveBeenCalled();
+  });
+
+  it("does not crash or navigate on malformed codex-file links", () => {
+    const items: ConversationItem[] = [
+      {
+        id: "msg-malformed-file-link",
+        kind: "message",
+        role: "assistant",
+        text: "Bad [path](codex-file:%E0%A4%A)",
+      },
+    ];
+
+    render(
+      <Messages
+        items={items}
+        threadId="thread-1"
+        workspaceId="ws-1"
+        isThinking={false}
+        openTargets={[]}
+        selectedOpenAppId=""
+      />,
+    );
+
+    fireEvent.click(screen.getByText("path"));
+    expect(openFileLinkMock).not.toHaveBeenCalled();
+  });
+
   it("hides file parent paths when message file path display is disabled", () => {
     const items: ConversationItem[] = [
       {