Add shared tool loop stop policy

test/tool-loop-control.test.mjs

@@ -0,0 +1,40 @@
+import test from "node:test";
+import assert from "node:assert/strict";
+
+const {decideToolLoopContinuation} = await import("../dist/ai/tool-loop-control.js");
+
+test("tool loop continuation stops when there are no tool calls", () => {
+    const decision = decideToolLoopContinuation({
+        round: 0,
+        maxRounds: 3,
+        toolCalls: [],
+    });
+
+    assert.equal(decision.continue, false);
+    assert.equal(decision.reason, "no_tool_calls");
+    assert.equal(decision.remainingRounds, 2);
+});
+
+test("tool loop continuation stops on the last allowed round", () => {
+    const decision = decideToolLoopContinuation({
+        round: 2,
+        maxRounds: 3,
+        toolCalls: [{id: "call-1", name: "read_file", argumentsText: "{}"}],
+    });
+
+    assert.equal(decision.continue, false);
+    assert.equal(decision.reason, "max_rounds_reached");
+    assert.equal(decision.remainingRounds, 0);
+});
+
+test("tool loop continuation allows further rounds when tools remain and rounds are left", () => {
+    const decision = decideToolLoopContinuation({
+        round: 1,
+        maxRounds: 3,
+        toolCalls: [{id: "call-1", name: "read_file", argumentsText: "{}"}],
+    });
+
+    assert.equal(decision.continue, true);
+    assert.equal(decision.reason, undefined);
+    assert.equal(decision.remainingRounds, 1);
+});