fix(desktop): make file:// chat links clickable

packages/desktop/src/main/external-link.test.ts

@@ -0,0 +1,19 @@
+import { describe, expect, test } from "bun:test"
+import { safeExternalUrl } from "./external-link"
+
+describe("safeExternalUrl", () => {
+  test("allows web links", () => {
+    expect(safeExternalUrl("https://opencode.ai/docs")).toBe("https://opencode.ai/docs")
+    expect(safeExternalUrl("http://localhost:3000/callback")).toBe("http://localhost:3000/callback")
+  })
+
+  test("rejects executable and application protocols", () => {
+    expect(safeExternalUrl("file:///tmp/script.sh")).toBeUndefined()
+    expect(safeExternalUrl("ssh://attacker.example")).toBeUndefined()
+    expect(safeExternalUrl("custom-handler:payload")).toBeUndefined()
+  })
+
+  test("rejects malformed URLs", () => {
+    expect(safeExternalUrl("not a url")).toBeUndefined()
+  })
+})

packages/desktop/src/main/external-link.ts

@@ -0,0 +1,8 @@
+const allowedProtocols = new Set(["https:", "http:"])
+
+export function safeExternalUrl(value: string) {
+  if (!URL.canParse(value)) return
+  const url = new URL(value)
+  if (!allowedProtocols.has(url.protocol)) return
+  return url.toString()
+}

packages/desktop/src/main/ipc.ts

@@ -8,6 +8,7 @@ import type { DesktopMenuAction } from "@opencode-ai/app/desktop-menu"
 import type { FatalRendererError, ServerReadyData, TitlebarTheme } from "../preload/types"
 import { runDesktopMenuAction } from "./desktop-menu-actions"
 import { setForceFocus } from "./debug"
+import { safeExternalUrl } from "./external-link"
 import { assertAttachmentBudget, createPickedFileAuthorizations } from "./attachment-picker"
 import { getStore, removeStoreFileIfEmpty } from "./store"
 import { getPinchZoomEnabled, getWindowID, setPinchZoomEnabled, setTitlebar, updateTitlebar } from "./windows"
@@ -178,7 +179,9 @@ export function registerIpcHandlers(deps: Deps) {
   )
 
   ipcMain.on("open-link", (_event: IpcMainEvent, url: string) => {
-    void shell.openExternal(url)
+    const externalUrl = safeExternalUrl(url)
+    if (!externalUrl) return
+    void shell.openExternal(externalUrl)
   })
 
   ipcMain.handle("open-path", async (_event: IpcMainInvokeEvent, path: string, app?: string) => {

packages/desktop/src/renderer/file-link.test.ts

@@ -0,0 +1,36 @@
+import { describe, expect, test } from "bun:test"
+import { isFileHref, pathFromFileHref } from "./file-link"
+
+describe("pathFromFileHref", () => {
+  test("parses unix file URLs", () => {
+    expect(pathFromFileHref("file:///Users/me/project/file.md")).toBe("/Users/me/project/file.md")
+    expect(pathFromFileHref("file:///tmp/opencode")).toBe("/tmp/opencode")
+  })
+
+  test("parses windows file URLs", () => {
+    expect(pathFromFileHref("file:///C:/Users/me/file.md")).toBe("C:/Users/me/file.md")
+  })
+
+  test("accepts bare absolute paths", () => {
+    expect(pathFromFileHref("/Users/me/project/file.md")).toBe("/Users/me/project/file.md")
+    expect(pathFromFileHref("C:\\Users\\me\\file.md")).toBe("C:/Users/me/file.md")
+  })
+
+  test("strips line and column suffixes", () => {
+    expect(pathFromFileHref("file:///Users/me/app.ts:12")).toBe("/Users/me/app.ts")
+    expect(pathFromFileHref("/Users/me/app.ts:12:4")).toBe("/Users/me/app.ts")
+  })
+
+  test("rejects web URLs", () => {
+    expect(pathFromFileHref("https://opencode.ai")).toBeUndefined()
+    expect(pathFromFileHref("http://localhost:3000")).toBeUndefined()
+  })
+})
+
+describe("isFileHref", () => {
+  test("detects file targets", () => {
+    expect(isFileHref("file:///tmp/x")).toBe(true)
+    expect(isFileHref("/tmp/x")).toBe(true)
+    expect(isFileHref("https://opencode.ai")).toBe(false)
+  })
+})

packages/desktop/src/renderer/file-link.ts

@@ -0,0 +1,40 @@
+/** Convert a file: URL (or absolute path href) into a filesystem path. */
+export function pathFromFileHref(href: string): string | undefined {
+  const value = href.trim()
+  if (!value) return
+
+  if (value.startsWith("/") && !value.startsWith("//")) {
+    return stripLocation(value)
+  }
+
+  if (/^[a-zA-Z]:[\\/]/.test(value)) {
+    return stripLocation(value.replace(/\\/g, "/"))
+  }
+
+  if (!URL.canParse(value)) return
+  const url = new URL(value)
+  if (url.protocol !== "file:") return
+
+  let path = decodeURIComponent(url.pathname)
+  // Windows file URLs are `/C:/...`
+  if (/^\/[a-zA-Z]:\//.test(path)) path = path.slice(1)
+  // UNC paths: file://server/share → pathname `/share`, host is server
+  if (url.hostname && url.hostname !== "localhost") {
+    path = `//${url.hostname}${path}`
+  }
+  return stripLocation(path) || undefined
+}
+
+function stripLocation(path: string) {
+  // Support `path:line` and `path:line:col` suffixes common in agent output.
+  // Keep Windows drive letters (`C:...`).
+  return path.replace(/:(\d+)(:\d+)?$/, (match, _line, _col, offset, full) => {
+    const before = full.slice(0, offset)
+    if (!before || /^[a-zA-Z]$/.test(before)) return match
+    return ""
+  })
+}
+
+export function isFileHref(href: string) {
+  return pathFromFileHref(href) !== undefined && (/^file:/i.test(href.trim()) || href.trim().startsWith("/") || /^[a-zA-Z]:[\\/]/.test(href.trim()))
+}

packages/desktop/src/renderer/index.tsx

@@ -27,6 +27,7 @@ import { DesktopFirstLaunchOnboarding } from "./onboarding"
 import { resetZoom, setPinchZoomEnabled, webviewZoom, zoomIn, zoomOut } from "./webview-zoom"
 import { windowFullscreen } from "./window-fullscreen"
 import { availableStartupServer, readyWslConnections } from "./wsl/connections"
+import { pathFromFileHref } from "./file-link"
 import "./styles.css"
 import { Splash } from "@opencode-ai/ui/logo"
 import { useTheme } from "@opencode-ai/ui/theme/context"
@@ -360,10 +361,25 @@ function DesktopRoot(props: { windowState: DesktopWindowState }) {
 
   function handleClick(e: MouseEvent) {
     const link = (e.target as HTMLElement).closest("a.external-link") as HTMLAnchorElement | null
-    if (link?.href) {
-      e.preventDefault()
-      platform.openLink(link.href)
+    if (!link?.href) return
+    e.preventDefault()
+
+    // Prefer the raw attribute so file: links aren't rewritten against oc://renderer.
+    const href = link.getAttribute("href") || link.href
+    const filePath = pathFromFileHref(href)
+    if (filePath) {
+      const reveal = e.metaKey || e.ctrlKey || e.altKey || e.button === 1
+      if (reveal && platform.revealPath) {
+        void platform.revealPath(filePath)
+        return
+      }
+      if (platform.openPath) {
+        void platform.openPath(filePath)
+        return
+      }
     }
+
+    platform.openLink(link.href)
   }
 
   function Inner() {

packages/session-ui/src/components/markdown-cache.tsx

@@ -1,5 +1,6 @@
 import { checksum } from "@opencode-ai/core/util/encode"
 import DOMPurify from "dompurify"
+import { desktopAllowedUriRegexp, isDesktopRenderer } from "./markdown-desktop"
 import { project } from "./markdown-stream"
 
 export type MarkdownCacheEntry = {
@@ -34,6 +35,11 @@ if (typeof window !== "undefined" && DOMPurify.isSupported) {
 
 export function sanitizeMarkdown(html: string) {
   if (!DOMPurify.isSupported) return ""
+  // Desktop: keep file: hrefs so chat path links stay clickable. Web keeps the
+  // default scheme allowlist (browsers block file: navigation anyway).
+  if (isDesktopRenderer()) {
+    return DOMPurify.sanitize(html, { ...config, ALLOWED_URI_REGEXP: desktopAllowedUriRegexp })
+  }
   return DOMPurify.sanitize(html, config)
 }
 

packages/session-ui/src/components/markdown-desktop.test.ts

@@ -0,0 +1,38 @@
+import { describe, expect, test } from "bun:test"
+import { absolutePathHref, desktopAllowedUriRegexp } from "./markdown-desktop"
+
+describe("absolutePathHref", () => {
+  test("converts unix absolute paths", () => {
+    expect(absolutePathHref("/Users/me/project/file.md")).toBe("file:///Users/me/project/file.md")
+    expect(absolutePathHref("`/tmp/x`")).toBeUndefined()
+  })
+
+  test("converts windows absolute paths", () => {
+    expect(absolutePathHref("C:\\Users\\me\\file.md")).toBe("file:///C:/Users/me/file.md")
+    expect(absolutePathHref("D:/repo/app.ts")).toBe("file:///D:/repo/app.ts")
+  })
+
+  test("passes through file URLs", () => {
+    expect(absolutePathHref("file:///tmp/opencode")).toBe("file:///tmp/opencode")
+  })
+
+  test("strips trailing punctuation and line numbers", () => {
+    expect(absolutePathHref("/Users/me/app.ts.")).toBe("file:///Users/me/app.ts")
+    expect(absolutePathHref("/Users/me/app.ts:12")).toBe("file:///Users/me/app.ts")
+    expect(absolutePathHref("/Users/me/app.ts:12:4")).toBe("file:///Users/me/app.ts")
+  })
+
+  test("rejects relative paths and web urls", () => {
+    expect(absolutePathHref("src/app.ts")).toBeUndefined()
+    expect(absolutePathHref("https://opencode.ai")).toBeUndefined()
+    expect(absolutePathHref("/")).toBeUndefined()
+  })
+})
+
+describe("desktopAllowedUriRegexp", () => {
+  test("allows file and web schemes", () => {
+    expect(desktopAllowedUriRegexp.test("file:///tmp/x")).toBe(true)
+    expect(desktopAllowedUriRegexp.test("https://opencode.ai")).toBe(true)
+    expect(desktopAllowedUriRegexp.test("http://localhost")).toBe(true)
+  })
+})

packages/session-ui/src/components/markdown-desktop.ts

@@ -0,0 +1,57 @@
+/** True when markdown is rendered inside the OpenCode desktop Electron shell. */
+export function isDesktopRenderer() {
+  if (typeof window === "undefined") return false
+  if (window.location.protocol === "oc:") return true
+  return typeof (window as Window & { api?: { openPath?: unknown } }).api?.openPath === "function"
+}
+
+/** DOMPurify default plus `file:` — only enable on desktop; browsers block file: anyway. */
+export const desktopAllowedUriRegexp =
+  /^(?:(?:(?:f|ht)tps?|file|mailto|tel|callto|sms|cid|xmpp):|[^a-z]|[a-z+.\-]+(?:[^a-z+.\-:]|$))/i
+
+function stripLineColumn(path: string) {
+  // `path:line` / `path:line:col` — keep Windows drive letters (`C:...`)
+  return path.replace(/:(\d+)(:\d+)?$/, (match, _line, _col, offset, full) => {
+    const before = full.slice(0, offset)
+    if (!before || /^[a-zA-Z]$/.test(before)) return match
+    return ""
+  })
+}
+
+function toFileHref(path: string) {
+  if (path.startsWith("/")) return `file://${encodeURI(path).replace(/#/g, "%23")}`
+  return `file:///${encodeURI(path).replace(/#/g, "%23")}`
+}
+
+/** Build a file: href from bare absolute path text, or return undefined. */
+export function absolutePathHref(text: string): string | undefined {
+  const href = text.trim().replace(/[),.;!?]+$/, "")
+  if (!href || /\s/.test(href)) return
+
+  // Already a file URL
+  if (/^file:\/\//i.test(href)) {
+    try {
+      const url = new URL(href)
+      let path = decodeURIComponent(url.pathname)
+      if (/^\/[a-zA-Z]:\//.test(path)) path = path.slice(1)
+      path = stripLineColumn(path)
+      if (!path || path === "/") return
+      return toFileHref(path)
+    } catch {
+      return
+    }
+  }
+
+  // Unix absolute
+  if (href.startsWith("/") && href.length > 1) {
+    const path = stripLineColumn(href)
+    if (path === "/") return
+    return toFileHref(path)
+  }
+
+  // Windows absolute
+  if (/^[a-zA-Z]:[\\/]/.test(href)) {
+    const path = stripLineColumn(href.replace(/\\/g, "/"))
+    return toFileHref(path)
+  }
+}

packages/session-ui/src/components/markdown.tsx

@@ -30,6 +30,7 @@ import {
 import { markdownBlockKey, type MarkdownToken } from "./markdown-worker-protocol"
 import { shouldResetCodeTokens, type RenderedCodeState } from "./markdown-code-state"
 import { getCachedMarkdown, sanitizeMarkdown, touchCachedMarkdown, type MarkdownCacheEntry } from "./markdown-cache"
+import { absolutePathHref, isDesktopRenderer } from "./markdown-desktop"
 import { inlineCodeKind } from "./markdown-inline-code-kind"
 
 type RenderedBlock =
@@ -99,13 +100,16 @@ const urlPattern = /^https?:\/\/[^\s<>()`"']+$/
 
 function codeUrl(text: string) {
   const href = text.trim().replace(/[),.;!?]+$/, "")
-  if (!urlPattern.test(href)) return
-  try {
-    const url = new URL(href)
-    return url.toString()
-  } catch {
-    return
+  if (urlPattern.test(href)) {
+    try {
+      return new URL(href).toString()
+    } catch {
+      return
+    }
   }
+  // Desktop only: turn absolute paths / file: URLs into clickable file links.
+  if (!isDesktopRenderer()) return
+  return absolutePathHref(href)
 }
 
 function createCopyButton(labels: CopyLabels) {