fix(core): decode cross-platform attachment paths

packages/core/src/session/runner/to-llm-message.ts

@@ -1,5 +1,6 @@
 import { Message, ToolCallPart, ToolResultPart, type ContentPart, type ProviderMetadata } from "@opencode-ai/ai"
 import { Option, Schema } from "effect"
+import { fileURLToPath } from "url"
 import type { Model } from "../../model"
 import { SessionMessage } from "../message"
 import type { FileAttachment } from "@opencode-ai/schema/prompt"
@@ -14,6 +15,13 @@ const media = (file: FileAttachment): ContentPart => ({
   metadata: file.description === undefined ? undefined : { description: file.description },
 })
 
+const attachmentLocation = (file: FileAttachment) => {
+  if (file.source.type !== "uri") return undefined
+  const url = URL.parse(file.source.uri)
+  if (url?.protocol !== "file:") return undefined
+  return fileURLToPath(url, { windows: url.hostname !== "" || /^\/[a-zA-Z]:\//.test(url.pathname) })
+}
+
 const textAttachment = (file: FileAttachment): ContentPart => ({
   type: "text",
   text: `\n\n${[
@@ -36,7 +44,7 @@ const textAttachment = (file: FileAttachment): ContentPart => ({
 const directoryAttachment = (file: FileAttachment): ContentPart => ({
   type: "text",
   text: `\n\n${[
-    `Attached directory: ${file.name ?? (file.source.type === "uri" ? file.source.uri : "directory")}`,
+    `Attached directory: ${attachmentLocation(file) ?? file.name ?? (file.source.type === "uri" ? file.source.uri : "directory")}`,
     file.description === undefined ? undefined : `Description: ${file.description}`,
     file.data.length === 0 ? undefined : "",
     file.data.length === 0 ? undefined : Buffer.from(file.data, "base64").toString("utf8"),
@@ -55,7 +63,10 @@ const directoryAttachment = (file: FileAttachment): ContentPart => ({
 const attachmentContent = (file: FileAttachment): ContentPart[] => {
   if (file.mime === "text/plain") return [textAttachment(file)]
   if (file.mime === "application/x-directory") return [directoryAttachment(file)]
-  if (imageMimes.has(file.mime)) return [media(file)]
+  if (imageMimes.has(file.mime)) {
+    const location = attachmentLocation(file)
+    return [...(location === undefined ? [] : [Message.text(`Attached file: ${location}`)]), media(file)]
+  }
   return []
 }
 

packages/core/test/session-runner-message.test.ts

@@ -249,13 +249,14 @@ Recent work
     ])
   })
 
-  test("lowers directory attachments as directory context", () => {
+  test("exposes admitted reference directory source paths in model context", () => {
     const directory = FileAttachment.make({
       data: Base64.make(Buffer.from("lib/\nindex.ts").toString("base64")),
       mime: "application/x-directory",
-      source: { type: "uri", uri: "file:///project/src" },
-      name: "src/",
+      source: { type: "uri", uri: "file:///references/harness-engineering" },
+      name: "harness-engineering",
     })
+    expect(directory.source).toEqual({ type: "uri", uri: "file:///references/harness-engineering" })
     const messages = toLLMMessages(
       [
         SessionMessage.User.make({
@@ -277,8 +278,8 @@ Recent work
         { type: "text", text: "Review this directory" },
         {
           type: "text",
-          text: "\n\nAttached directory: src/\n\nlib/\nindex.ts",
-          metadata: { attachment: { source: directory.source, name: "src/" } },
+          text: "\n\nAttached directory: /references/harness-engineering\n\nlib/\nindex.ts",
+          metadata: { attachment: { source: directory.source, name: "harness-engineering" } },
         },
       ],
     })
@@ -314,7 +315,7 @@ Recent work
     expect(messages).toHaveLength(1)
     expect(messages[0]?.content.map((part) => (part.type === "text" ? part.text : part.type))).toEqual([
       "Review these attachments",
-      "\n\nAttached directory: src/\n\nindex.ts",
+      "\n\nAttached directory: /project/src\n\nindex.ts",
       "\n\nAttached file: main.ts\n\nexport const value = 1",
     ])
   })
@@ -341,7 +342,9 @@ Recent work
     )
 
     expect(messages).toHaveLength(1)
-    expect(messages[0]?.content).toMatchObject([{ type: "text", text: "\n\nAttached directory: src/\n\nindex.ts" }])
+    expect(messages[0]?.content).toMatchObject([
+      { type: "text", text: "\n\nAttached directory: /project/src\n\nindex.ts" },
+    ])
   })
 
   test("uses materialized image data as provider media and drops unsupported attachments", () => {
@@ -373,6 +376,64 @@ Recent work
     ])
   })
 
+  test("exposes admitted local image source paths before provider media", () => {
+    const data = Base64.make("AAECAw==")
+    const image = FileAttachment.make({
+      data,
+      mime: "image/png",
+      source: { type: "uri", uri: "file:///project/IMG_3480.JPG" },
+      name: "IMG_3480.JPG",
+    })
+    expect(image.source).toEqual({ type: "uri", uri: "file:///project/IMG_3480.JPG" })
+
+    const messages = toLLMMessages(
+      [
+        SessionMessage.User.make({
+          id: id("user-local-image-path"),
+          type: "user",
+          text: "Inspect this image",
+          files: [image],
+          time: { created },
+        }),
+      ],
+      model,
+    )
+
+    expect(messages[0]?.content).toEqual([
+      { type: "text", text: "Inspect this image" },
+      { type: "text", text: "Attached file: /project/IMG_3480.JPG" },
+      { type: "media", mediaType: "image/png", data, filename: "IMG_3480.JPG" },
+    ])
+  })
+
+  test("does not add attachment location text for non-local provider media", () => {
+    const data = Base64.make("AAECAw==")
+    const messages = toLLMMessages(
+      [
+        SessionMessage.User.make({
+          id: id("user-remote-image"),
+          type: "user",
+          text: "Inspect this image",
+          files: [
+            FileAttachment.make({
+              data,
+              mime: "image/png",
+              source: { type: "uri", uri: "https://example.com/image.png" },
+              name: "image.png",
+            }),
+          ],
+          time: { created },
+        }),
+      ],
+      model,
+    )
+
+    expect(messages[0]?.content).toEqual([
+      { type: "text", text: "Inspect this image" },
+      { type: "media", mediaType: "image/png", data, filename: "image.png" },
+    ])
+  })
+
   test("deduplicates provider media while preserving durable attachment references", () => {
     const data = Base64.make("AAECAw==")
     const messages = toLLMMessages(