fix(message-tool): allow buffer-only attachments without media path or url (#90768)

lonexreb · lonexreb · commit 94c60cc4dc7c · 2026-06-05T22:07:28.000-04:00
diff --git a/src/infra/outbound/message-action-params.test.ts b/src/infra/outbound/message-action-params.test.ts
@@ -578,6 +578,35 @@ describe("message action media helpers", () => {
     expect(args.contentType).toBeUndefined();
   });
 
+  it("promotes buffer-only structured attachments to top-level args (#90768)", async () => {
+    // Buffer-only attachments (no media/path/url) used to be invisible to the
+    // structured-attachment resolver, so message.send/reply with just a
+    // base64 buffer + filename + contentType silently dropped the file.
+    const base64 = Buffer.from("hello-bytes").toString("base64");
+    const args: Record<string, unknown> = {
+      attachments: [
+        {
+          buffer: base64,
+          filename: "memo.txt",
+          contentType: "text/plain",
+        },
+      ],
+    };
+
+    await hydrateAttachmentParamsForAction({
+      cfg,
+      channel: "imessage",
+      args,
+      action: "sendAttachment",
+      dryRun: true,
+      mediaPolicy: { mode: "host" },
+    });
+
+    expect(args.buffer).toBe(base64);
+    expect(args.filename).toBe("memo.txt");
+    expect(args.contentType).toBe("text/plain");
+  });
+
   it("does not fall back caption->message on reply (reply has its own text field)", async () => {
     // sendAttachment uses caption as the body text and falls back from
     // message -> caption when the agent only supplied `message`. Reply has
diff --git a/src/infra/outbound/message-action-params.ts b/src/infra/outbound/message-action-params.ts
@@ -49,7 +49,7 @@ type StructuredAttachmentSource = {
   attachment: Record<string, unknown>;
   key: string;
   value: string;
-  kind: "media" | "file";
+  kind: "media" | "file" | "buffer";
   contentType?: string;
   filename?: string;
 };
@@ -107,6 +107,7 @@ function collectStructuredAttachmentSources(
     if (!isRecord(attachment)) {
       continue;
     }
+    let matched = false;
     for (const key of STRUCTURED_ATTACHMENT_MEDIA_SOURCE_PARAM_KEYS) {
       const entry = resolveMediaParamEntry(attachment, key);
       if (!entry || !normalizeOptionalString(entry.value)) {
@@ -121,8 +122,31 @@ function collectStructuredAttachmentSources(
           readStringParam(attachment, "contentType") ?? readStringParam(attachment, "mimeType"),
         filename: readStringParam(attachment, "filename") ?? readStringParam(attachment, "name"),
       });
+      matched = true;
       break;
     }
+    if (matched) {
+      continue;
+    }
+    // Buffer-only attachments carry no media path/URL; surface them so the
+    // runner can hydrate the buffer onto top-level args before channel dispatch.
+    const bufferKey = resolveSnakeCaseParamKey(attachment, "buffer");
+    if (!bufferKey) {
+      continue;
+    }
+    const bufferValue = readStringParam(attachment, "buffer", { trim: false });
+    if (!bufferValue) {
+      continue;
+    }
+    sources.push({
+      attachment,
+      key: bufferKey,
+      value: bufferValue,
+      kind: "buffer",
+      contentType:
+        readStringParam(attachment, "contentType") ?? readStringParam(attachment, "mimeType"),
+      filename: readStringParam(attachment, "filename") ?? readStringParam(attachment, "name"),
+    });
   }
   return sources;
 }
@@ -502,6 +526,15 @@ async function hydrateAttachmentActionPayload(params: {
   if (attachmentSource?.contentType && !readStringParam(params.args, "contentType")) {
     params.args.contentType = attachmentSource.contentType;
   }
+  // Buffer-only structured attachments carry no media path/URL. Promote the
+  // raw base64 to top-level args so downstream hydration treats them like a
+  // direct buffer send instead of dropping the attachment.
+  if (
+    attachmentSource?.kind === "buffer" &&
+    !readStringParam(params.args, "buffer", { trim: false })
+  ) {
+    params.args.buffer = attachmentSource.value;
+  }
 
   if (params.allowMessageCaptionFallback) {
     const caption = readStringParam(params.args, "caption", { allowEmpty: true })?.trim();
