From d537fb8ae3254d1d6691ee0b7202a2f3ab7ea977 Mon Sep 17 00:00:00 2001
From: ivanmilevtues <ivanmilevtues@gmail.com>
Date: Sat, 10 Oct 2026 21:27:05 +0200
Subject: [PATCH] feat(agent): count tool calls and failures per tool

---
 packages/agent/src/agent-loop.ts      |  2 ++
 packages/agent/src/index.ts           |  1 +
 packages/agent/src/tool-call-stats.ts | 28 +++++++++++++++++++++++++++
 3 files changed, 31 insertions(+)
 create mode 100644 packages/agent/src/tool-call-stats.ts

diff --git a/packages/agent/src/agent-loop.ts b/packages/agent/src/agent-loop.ts
index f406aba5647a..d6b962e6d443 100644
--- a/packages/agent/src/agent-loop.ts
+++ b/packages/agent/src/agent-loop.ts
@@ -16,6 +16,7 @@ import {
 	validateToolArguments,
 } from "@earendil-works/pi-ai";
 import { getDefaultStreamFn } from "./stream-fn.ts";
+import { recordToolCall } from "./tool-call-stats.ts";
 import type {
 	AgentContext,
 	AgentEvent,
@@ -269,6 +270,7 @@ async function runLoop(
 						? await failToolCallsFromTruncatedMessage(toolCalls, emit)
 						: await executeToolCalls(currentContext, message, config, signal, emit);
 				toolResults.push(...executedToolBatch.messages);
+				for (const result of executedToolBatch.messages) recordToolCall(result.toolName, result.isError);
 				hasMoreToolCalls = !executedToolBatch.terminate;
 
 				for (const result of toolResults) {
diff --git a/packages/agent/src/index.ts b/packages/agent/src/index.ts
index ca00bc777266..2d39b6f4ed8e 100644
--- a/packages/agent/src/index.ts
+++ b/packages/agent/src/index.ts
@@ -2,4 +2,5 @@ export * from "./agent.ts";
 export * from "./agent-loop.ts";
 export * from "./proxy.ts";
 export { setDefaultStreamFn } from "./stream-fn.ts";
+export * from "./tool-call-stats.ts";
 export * from "./types.ts";
diff --git a/packages/agent/src/tool-call-stats.ts b/packages/agent/src/tool-call-stats.ts
new file mode 100644
index 000000000000..9dc59a85d345
--- /dev/null
+++ b/packages/agent/src/tool-call-stats.ts
@@ -0,0 +1,28 @@
+/**
+ * Per-tool call counts for the current process, so a session can report which tools the
+ * agent leaned on and how many of their calls failed.
+ */
+export interface ToolCallStat {
+	calls: number;
+	errors: number;
+}
+
+const stats = new Map<string, ToolCallStat>();
+
+export function recordToolCall(toolName: string, isError: boolean): void {
+	const stat = stats.get(toolName) ?? { calls: 0, errors: 0 };
+	stat.calls += 1;
+	if (isError) stat.errors += 1;
+	stats.set(toolName, stat);
+}
+
+/** A snapshot, most-called tool first. */
+export function getToolCallStats(): Array<{ toolName: string } & ToolCallStat> {
+	return [...stats.entries()]
+		.map(([toolName, stat]) => ({ toolName, ...stat }))
+		.sort((a, b) => b.calls - a.calls);
+}
+
+export function resetToolCallStats(): void {
+	stats.clear();
+}