From 3399f4b95386803e9c378982abfeaab65ed54e50 Mon Sep 17 00:00:00 2001
From: Rach Pradhan <54503978+justrach@users.noreply.github.com>
Date: Sat, 1 Aug 2026 14:14:33 +0800
Subject: [PATCH] feat(events): id + result text on workflow subagent tool
 events

Workflow subagent tool_call/tool_result events carried neither an id nor
the child's report, so a --json consumer rendering the live agent tree
could only pair parallel rows by arrival order and had no failure reason
to show. Reuse the sa- id agent_usage already emits on both events, and
put the report head (or the API error) on tool_result.

Port of June's bb090f1 (feat/live-agent-tree) onto the split-out
subagent_run.zig, switched from that commit's call_id to the id field
the protocol already uses for subagent identity.

Co-Authored-By: Codegraff <blackfloofie@codegraff.com>
---
 src/schema_protocol.zig |  4 ++--
 src/subagent_run.zig    | 12 ++++++++++--
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/schema_protocol.zig b/src/schema_protocol.zig
index 7ccecaea..b90992a2 100644
--- a/src/schema_protocol.zig
+++ b/src/schema_protocol.zig
@@ -39,11 +39,11 @@ pub const json =
     \\    {"type": "started", "provider": "provider", "model": "model"},
     \\    {"type": "model_call_started", "provider": "provider", "model": "model"},
     \\    {"type": "model_call_finished", "provider": "provider", "model": "model", "ok": true, "ms": 0},
-    \\    {"type": "tool_call", "name": "tool", "input": {}},
+    \\    {"type": "tool_call", "name": "tool", "input": {}, "id": "sa-… on workflow subagent rows only; pairs with tool_result/agent_usage"},
     \\    {"type": "tool_call_started", "name": "tool", "input": {}},
     \\    {"type": "tool_rejected", "name": "tool", "reason": "budget|duplicate", "input": {}, "message": "..."},
     \\    {"type": "ask_user", "call_id": "...", "question": "...", "input": {"question": "...", "options": ["..."]}},
-    \\    {"type": "tool_result", "name": "tool", "is_error": false, "text": "..."},
+    \\    {"type": "tool_result", "name": "tool", "is_error": false, "text": "...", "id": "sa-… on workflow subagent rows only"},
     \\    {"type": "tool_call_finished", "name": "tool", "is_error": false, "ms": 0},
     \\    {"type": "agent_usage", "id": "sa-...", "ok": true, "duration_ms": 0, "tool_calls": 0, "context_tokens": 0, "cache_read_tokens": 0},
     \\    {"type": "finalizing"},
diff --git a/src/subagent_run.zig b/src/subagent_run.zig
index 44e21f56..d61bb99f 100644
--- a/src/subagent_run.zig
+++ b/src/subagent_run.zig
@@ -255,7 +255,7 @@ pub fn runSub(ctx: ToolCtx, kind: []const u8, label: []const u8, prompt: []const
     agent.agent_cwd = if (wt) |w| w.path else null;
 
     const wf_task = std.mem.eql(u8, kind, "workflow_task");
-    if (wf_task) guiEmit(ctx.io, .{ .type = "tool_call", .name = "subagent", .input = .{ .description = label } });
+    if (wf_task) guiEmit(ctx.io, .{ .type = "tool_call", .name = "subagent", .input = .{ .description = label }, .id = sub_id });
     // A /loop deadline on the parent reaches the child as guidance on its own
     // task prompt (goal_pacing.childTaskPrompt): same absolute deadline, minus
     // the margin the parent needs to integrate the result. No-op without one.
@@ -265,7 +265,15 @@ pub fn runSub(ctx: ToolCtx, kind: []const u8, label: []const u8, prompt: []const
     const report = agent.runTurn();
     const run_ms: i64 = @intCast(@max(0, sub_start.untilNow(ctx.io, .awake).toMilliseconds()));
     const run_ok = if (report) |r| r.len > 0 else |_| false;
-    if (wf_task) guiEmit(ctx.io, .{ .type = "tool_result", .name = "subagent", .is_error = !run_ok });
+    if (wf_task) {
+        // The sa- id (shared with agent_usage) pairs parallel workflow rows;
+        // without it a consumer can only match tool_call/tool_result by order.
+        const sub_report: []const u8 = if (report) |r|
+            (if (r.len > 0) r else "subagent returned no report")
+        else |_|
+            (agent.last_api_error orelse "subagent failed");
+        guiEmit(ctx.io, .{ .type = "tool_result", .name = "subagent", .is_error = !run_ok, .text = util.utf8Prefix(sub_report, 600), .id = sub_id });
+    }
     const used_tools = agent.tools_used.render(arena);
     const usage: AgentUsage = .{
         .duration_ms = @intCast(run_ms),