1 files changed, 47 insertions, 2 deletions
diff --git a/libpanto/src/conversation.zig b/libpanto/src/conversation.zig
index 780f650..2c29f8e 100644
--- a/libpanto/src/conversation.zig
+++ b/libpanto/src/conversation.zig
@@ -41,13 +41,58 @@ pub const ToolUseBlock = struct {
     }
 };
 
+/// A binary attachment stored in a tool result. `media_type` is owned
+/// (e.g. "image/png"); `data` is the streaming text buffer holding
+/// base64-encoded bytes.
+pub const StoredMediaPart = struct {
+    media_type: []const u8,
+    data: TextualBlock = .empty,
+
+    pub fn deinit(self: *StoredMediaPart, alloc: Allocator) void {
+        alloc.free(self.media_type);
+        self.data.deinit(alloc);
+    }
+};
+
+/// One part of a tool result as stored in the conversation. Text uses the
+/// streaming `TextualBlock` form to preserve incremental-append semantics.
+pub const ResultPartStored = union(enum) {
+    text: TextualBlock,
+    media: StoredMediaPart,
+
+    pub fn deinit(self: *ResultPartStored, alloc: Allocator) void {
+        switch (self.*) {
+            .text => |*t| t.deinit(alloc),
+            .media => |*m| m.deinit(alloc),
+        }
+    }
+};
+
 pub const ToolResultBlock = struct {
     tool_use_id: []const u8,
-    content: TextualBlock = .empty,
+    parts: std.ArrayList(ResultPartStored) = .empty,
 
     pub fn deinit(self: *ToolResultBlock, alloc: Allocator) void {
         alloc.free(self.tool_use_id);
-        self.content.deinit(alloc);
+        for (self.parts.items) |*p| p.deinit(alloc);
+        self.parts.deinit(alloc);
+    }
+
+    /// Concatenate all text parts into `out`. Media parts are skipped.
+    /// Used by callers (compaction, OpenAI fan-out) that want only the
+    /// textual portion.
+    pub fn appendTextInto(self: ToolResultBlock, alloc: Allocator, out: *TextualBlock) !void {
+        for (self.parts.items) |p| {
+            if (p == .text) try out.appendSlice(alloc, p.text.items);
+        }
+    }
+
+    /// True if any part is a media attachment.
+    pub fn hasMedia(self: ToolResultBlock) bool {
+        for (self.parts.items) |p| {
+            if (p == .media) return true;
+        }
+        return false;
     }
 };