Support subagent transcript viewing for Agent tool calls (#76)

## Summary
Claude Code renamed its subagent tool from `Task` to `Agent`. This adds
`Agent` handling across parser, taxonomy, frontend, and subagent
transcript rendering so it works identically to `Task`.

## Key changes
- Parse `agent_progress` events to map Agent tool calls to subagent
session IDs
- Normalize `Agent` to `Task` category in tool taxonomy
- Extend `SubagentInline` rendering and content-parser regex to cover
Agent
- Add Agent tool name mapping and normalization tests

Author: thellert

frontend/src/lib/components/content/ToolBlock.svelte

@@ -8,6 +8,11 @@
     generateFallbackContent,
   } from "../../utils/tool-params.js";
 
+  /** Returns true for tool names that represent a subagent call ("Task" or "Agent"). */
+  function isSubagentTool(name: string | undefined): boolean {
+    return name === "Task" || name === "Agent";
+  }
+
   interface Props {
     content: string;
     label?: string;
@@ -33,7 +38,7 @@
 
   /** For Task tool calls, extract key metadata fields */
   let taskMeta = $derived.by(() => {
-    if (toolCall?.tool_name !== "Task" || !inputParams)
+    if (!isSubagentTool(toolCall?.tool_name) || !inputParams)
       return null;
     const meta: { label: string; value: string }[] = [];
     if (inputParams.subagent_type) {
@@ -107,13 +112,13 @@
   });
 
   let taskPrompt = $derived(
-    toolCall?.tool_name === "Task"
+    isSubagentTool(toolCall?.tool_name)
       ? inputParams?.prompt ?? null
       : null,
   );
 
   let subagentSessionId = $derived(
-    toolCall?.tool_name === "Task"
+    isSubagentTool(toolCall?.tool_name)
       ? toolCall?.subagent_session_id ?? null
       : null,
   );

frontend/src/lib/utils/content-parser.ts

@@ -27,13 +27,14 @@ const THINKING_LEGACY_RE =
   /\[Thinking\]\n?([\s\S]*?)(?=\n\[|\n\n|$)/g;
 
 const TOOL_NAMES =
-  "Tool|Read|Write|Edit|Bash|Glob|Grep|Other|TaskCreate|TaskUpdate|TaskGet|TaskList|Task|Skill|" +
+  "Tool|Read|Write|Edit|Bash|Glob|Grep|Other|TaskCreate|TaskUpdate|TaskGet|TaskList|Task|Agent|Skill|" +
   "SendMessage|Question|Todo List|Entering Plan Mode|" +
   "Exiting Plan Mode|exec_command|shell_command|" +
   "write_stdin|apply_patch|shell|parallel|view_image|" +
   "request_user_input|update_plan";
 
 const TOOL_ALIASES: Record<string, string> = {
+  Agent: "Task",
   exec_command: "Bash",
   shell_command: "Bash",
   write_stdin: "Bash",

frontend/src/lib/utils/tool-params.ts

@@ -106,7 +106,7 @@ export function generateFallbackContent(
   toolName: string,
   params: Params,
 ): string | null {
-  if (toolName === "Task") return null;
+  if (toolName === "Task" || toolName === "Agent") return null;
   if (toolName === "Edit") {
     const lines: string[] = [];
     if (params.old_string != null) {

internal/parser/claude.go

@@ -116,6 +116,19 @@ func ParseClaudeSession(
 			continue
 		}
 
+		// Collect agent_progress events for subagent mapping.
+		// Claude Code v2.1+ emits these instead of queue-operation for Agent tool calls.
+		if entryType == "progress" {
+			if gjson.Get(line, "data.type").Str == "agent_progress" {
+				tuid := gjson.Get(line, "parentToolUseID").Str
+				agentID := gjson.Get(line, "data.agentId").Str
+				if tuid != "" && agentID != "" {
+					subagentMap[tuid] = "agent-" + agentID
+				}
+			}
+			continue
+		}
+
 		if entryType != "user" && entryType != "assistant" {
 			continue
 		}
@@ -495,7 +508,7 @@ func annotateSubagentSessions(
 	for i := range messages {
 		for j := range messages[i].ToolCalls {
 			tc := &messages[i].ToolCalls[j]
-			if tc.ToolName == "Task" && tc.ToolUseID != "" {
+			if (tc.ToolName == "Task" || tc.ToolName == "Agent") && tc.ToolUseID != "" {
 				if sid, ok := subagentMap[tc.ToolUseID]; ok {
 					tc.SubagentSessionID = sid
 				}

internal/parser/claude_subagent_test.go

@@ -62,6 +62,18 @@ func TestSubagentSessionIDMapping(t *testing.T) {
 				{ToolUseID: "toolu_xyz789", ToolName: "Task", Category: "Task", SubagentSessionID: "agent-cafebabe"},
 			},
 		},
+		{
+			name: "Agent Tool Name",
+			lines: []string{
+				`{"type":"user","timestamp":"2024-01-01T10:00:00Z","uuid":"u1","message":{"content":"hello"},"cwd":"/tmp"}`,
+				`{"type":"assistant","timestamp":"2024-01-01T10:00:01Z","uuid":"u2","parentUuid":"u1","message":{"content":[{"type":"tool_use","id":"toolu_agent1","name":"Agent","input":{"description":"explore codebase","subagent_type":"general-purpose","prompt":"find all API endpoints"}}]}}`,
+				`{"type":"queue-operation","operation":"enqueue","timestamp":"2024-01-01T10:00:01Z","sessionId":"test-session","content":"{\"task_id\":\"agent789\",\"tool_use_id\":\"toolu_agent1\",\"description\":\"explore codebase\",\"task_type\":\"local_agent\"}"}`,
+				`{"type":"user","timestamp":"2024-01-01T10:00:05Z","uuid":"u3","parentUuid":"u2","message":{"content":[{"type":"tool_result","tool_use_id":"toolu_agent1","content":"found 5 endpoints"}]}}`,
+			},
+			wantTools: []ParsedToolCall{
+				{ToolUseID: "toolu_agent1", ToolName: "Agent", Category: "Task", SubagentSessionID: "agent-agent789"},
+			},
+		},
 		{
 			name: "Non-Task Tool Unchanged",
 			lines: []string{
@@ -98,6 +110,19 @@ func TestSubagentSessionIDMapping(t *testing.T) {
 				{ToolUseID: "toolu_01XYZ", ToolName: "Task", Category: "Task", SubagentSessionID: "agent-beef4567"},
 			},
 		},
+		{
+			name: "Agent Progress Events",
+			lines: []string{
+				`{"type":"user","timestamp":"2024-01-01T10:00:00Z","uuid":"u1","message":{"content":"hello"},"cwd":"/tmp"}`,
+				`{"type":"assistant","timestamp":"2024-01-01T10:00:01Z","uuid":"u2","parentUuid":"u1","message":{"content":[{"type":"tool_use","id":"toolu_bdrk_01Wt5","name":"Agent","input":{"description":"wiki search","subagent_type":"wiki-search","prompt":"search wiki"}}]}}`,
+				`{"type":"progress","timestamp":"2024-01-01T10:00:02Z","parentToolUseID":"toolu_bdrk_01Wt5","data":{"type":"agent_progress","agentId":"a78243c84a44ebcd4","message":{"type":"user","message":{"role":"user","content":[{"type":"text","text":"search wiki"}]}}}}`,
+				`{"type":"progress","timestamp":"2024-01-01T10:00:03Z","parentToolUseID":"toolu_bdrk_01Wt5","data":{"type":"agent_progress","agentId":"a78243c84a44ebcd4","message":{"type":"assistant","message":{"role":"assistant","content":[{"type":"text","text":"found it"}]}}}}`,
+				`{"type":"user","timestamp":"2024-01-01T10:00:05Z","uuid":"u3","parentUuid":"u2","message":{"content":[{"type":"tool_result","tool_use_id":"toolu_bdrk_01Wt5","content":"wiki results"}]}}`,
+			},
+			wantTools: []ParsedToolCall{
+				{ToolUseID: "toolu_bdrk_01Wt5", ToolName: "Agent", Category: "Task", SubagentSessionID: "agent-a78243c84a44ebcd4"},
+			},
+		},
 		{
 			name: "Multiple Subagents",
 			lines: []string{

internal/parser/codex.go

@@ -374,7 +374,7 @@ func codexCategoryDetail(
 			return fmt.Sprintf("%s in %s", pattern, path)
 		}
 		return firstNonEmpty(pattern, path)
-	case "Task":
+	case "Task", "Agent":
 		desc := codexArgValue(args, "description")
 		agent := codexArgValue(args, "subagent_type")
 		if desc != "" && agent != "" {

internal/parser/codex_parser_test.go

@@ -94,6 +94,22 @@ func TestParseCodexSession_FunctionCalls(t *testing.T) {
 		assertToolCalls(t, msgs[1].ToolCalls, []ParsedToolCall{{ToolName: "write_stdin", Category: "Bash"}})
 	})
 
+	t.Run("Agent function call normalizes to Task category", func(t *testing.T) {
+		content := testjsonl.JoinJSONL(
+			testjsonl.CodexSessionMetaJSON("fc-agent", "/tmp", "user", tsEarly),
+			testjsonl.CodexMsgJSON("user", "explore code", tsEarlyS1),
+			testjsonl.CodexFunctionCallArgsJSON("Agent", map[string]any{
+				"description":   "explore codebase",
+				"subagent_type": "Explore",
+			}, tsEarlyS5),
+		)
+		sess, msgs := runCodexParserTest(t, "test.jsonl", content, false)
+		assert.Equal(t, "codex:fc-agent", sess.ID)
+		assert.Equal(t, 2, len(msgs))
+		assert.Contains(t, msgs[1].Content, "[Task: explore codebase (Explore)]")
+		assertToolCalls(t, msgs[1].ToolCalls, []ParsedToolCall{{ToolName: "Agent", Category: "Task"}})
+	})
+
 	t.Run("function call no name skipped", func(t *testing.T) {
 		content := testjsonl.JoinJSONL(
 			testjsonl.CodexSessionMetaJSON("fc-2", "/tmp", "user", tsEarly),

internal/parser/content.go

@@ -162,7 +162,7 @@ func formatToolUse(block gjson.Result) string {
 			skill = input.Get("name").Str
 		}
 		return fmt.Sprintf("[Skill: %s]", skill)
-	case "Task":
+	case "Task", "Agent":
 		return formatTask(input)
 	case "Skill":
 		return fmt.Sprintf("[Skill: %s]", input.Get("skill").Str)

internal/parser/parser_test.go

@@ -374,6 +374,11 @@ func TestFormatToolUseVariants(t *testing.T) {
 			`{"type":"tool_use","name":"Task","input":{"description":"explore","subagent_type":"Explore"}}`,
 			"[Task: explore (Explore)]",
 		},
+		{
+			"Agent",
+			`{"type":"tool_use","name":"Agent","input":{"description":"explore","subagent_type":"Explore"}}`,
+			"[Task: explore (Explore)]",
+		},
 		{
 			"EnterPlanMode",
 			`{"type":"tool_use","name":"EnterPlanMode","input":{}}`,

internal/parser/taxonomy.go

@@ -18,7 +18,7 @@ func NormalizeToolCategory(rawName string) string {
 		return "Grep"
 	case "Glob":
 		return "Glob"
-	case "Task":
+	case "Task", "Agent":
 		return "Task"
 	case "Skill":
 		return "Tool"