Stream OpenAI tool_use as discrete blocks; drop BlockMeta

Close each tool_use on next-index delta (and at finalize) so receivers
see one start/delta/complete trio per tool, matching Anthropic. Log+drop
fragments for already-closed indices.

Remove BlockMeta from the Receiver interface: tool id/name can't be
reliably known at onBlockStart under OpenAI's streaming model. Receivers
get identity from the assembled ContentBlock at onBlockComplete. CLI
renders 'tool: {args} : (name)' accordingly.

1 files changed, 8 insertions, 13 deletions

diff --git a/libpanto/src/provider_anthropic_messages.zig b/libpanto/src/provider_anthropic_messages.zig
index 7511ce8..03c1d90 100644
--- a/libpanto/src/provider_anthropic_messages.zig
+++ b/libpanto/src/provider_anthropic_messages.zig
@@ -257,7 +257,8 @@ const StreamState = struct {
         receiver: *provider_mod.Receiver,
         wire_index: usize,
         kind: BlockKind,
-        tool_meta: ?provider_mod.BlockMeta,
+        tool_id: ?[]const u8,
+        tool_name: ?[]const u8,
     ) !void {
         // Defensive: if a prior block didn't get an explicit stop, drop it.
         if (self.active != null) {
@@ -267,12 +268,11 @@ const StreamState = struct {
             .wire_index = wire_index,
             .kind = kind,
         };
-        // For tool_use blocks, capture the identity fields from the meta.
+        // For tool_use blocks, capture the identity fields. Anthropic
+        // delivers both whole on content_block_start.
         if (kind == .tool_use) {
-            if (tool_meta) |m| {
-                if (m.tool_id) |id| ab.tool_id = try self.allocator.dupe(u8, id);
-                if (m.tool_name) |n| ab.tool_name = try self.allocator.dupe(u8, n);
-            }
+            if (tool_id) |id| ab.tool_id = try self.allocator.dupe(u8, id);
+            if (tool_name) |n| ab.tool_name = try self.allocator.dupe(u8, n);
         }
         self.active = ab;
         const block_type: ?provider_mod.ContentBlockType = switch (kind) {
@@ -282,7 +282,7 @@ const StreamState = struct {
             .unsupported => null,
         };
         if (block_type) |bt| {
-            try receiver.onBlockStart(bt, wire_index, tool_meta);
+            try receiver.onBlockStart(bt, wire_index);
         }
     }
 
@@ -418,11 +418,7 @@ fn handleEvent(
                 .tool_use => .tool_use,
                 .unknown => .unsupported,
             };
-            const meta: ?provider_mod.BlockMeta = if (s.kind == .tool_use)
-                .{ .tool_id = s.tool_id, .tool_name = s.tool_name }
-            else
-                null;
-            try state.openBlock(receiver, s.index, kind, meta);
+            try state.openBlock(receiver, s.index, kind, s.tool_id, s.tool_name);
         },
         .content_block_delta => |d| {
             if (d.text_delta) |t| try state.appendTextDelta(receiver, t);
@@ -524,7 +520,6 @@ const RecordingReceiver = struct {
         ptr: *anyopaque,
         bt: provider_mod.ContentBlockType,
         idx: usize,
-        _: ?provider_mod.BlockMeta,
     ) anyerror!void {
         const self: *RecordingReceiver = @ptrCast(@alignCast(ptr));
         try self.events.append(self.allocator, .{ .block_start = .{ .kind = bt, .index = idx } });