feat(agent): added agent tool-call cap enforcement to stream loop

- Added `maxToolCallsPerTurn` support to `AgentOptions` and `AgentLoopConfig`, with Agent getter/setter and serialized state wiring.
- Implemented stream-loop cap handling by normalizing bad values and halting after `toolcall_end` reaches the limit.
- Added `ANTHROPIC_TOOL_CALL_BATCH_CAP`=8 and wired session cap sync on init, model changes, and restore.
- Added tests that truncated a 10-call stream to 8 tool calls, and verified non-Claude models resolve no cap.

packages/coding-agent/src/session/agent-session.ts

@@ -453,6 +453,15 @@ function formatRetryFallbackBaseSelector(selector: RetryFallbackSelector): strin
 }
 
 const IRC_REPLY_MAX_BYTES = 4096;
+export const ANTHROPIC_TOOL_CALL_BATCH_CAP = 4;
+const CLAUDE_OPUS_4_8_MODEL_ID = /(?:^|[./_-])claude-opus-4[.-]8\b/i;
+
+export function resolveToolCallBatchCapForModel(model: Model | undefined): number | undefined {
+	if (!model) return undefined;
+	return model.provider === "anthropic" && CLAUDE_OPUS_4_8_MODEL_ID.test(model.id)
+		? ANTHROPIC_TOOL_CALL_BATCH_CAP
+		: undefined;
+}
 
 /**
  * Collapse degenerate IRC ephemeral replies before they hit the relay.
@@ -993,6 +1002,10 @@ export class AgentSession {
 		this.#flushPendingAgentEnd();
 	}
 
+	#syncToolCallBatchCap(model: Model | undefined = this.model): void {
+		this.agent.maxToolCallsPerTurn = resolveToolCallBatchCapForModel(model);
+	}
+
 	#flushPendingAgentEnd(): void {
 		const pending = this.#pendingAgentEndEmit;
 		if (!pending) return;
@@ -1097,6 +1110,7 @@ export class AgentSession {
 		this.#agentId = config.agentId;
 		this.#agentRegistry = config.agentRegistry;
 		this.#providerSessionId = config.providerSessionId;
+		this.#syncToolCallBatchCap();
 		this.agent.setAssistantMessageEventInterceptor((message, assistantMessageEvent) => {
 			const event: AgentEvent = {
 				type: "message_update",
@@ -6162,6 +6176,7 @@ export class AgentSession {
 			this.#closeProviderSessionsForModelSwitch(currentModel, model);
 		}
 		this.agent.setModel(model);
+		this.#syncToolCallBatchCap(model);
 
 		// Re-evaluate append-only context mode — provider or setting may have changed
 		this.#syncAppendOnlyContext(model);
@@ -8214,6 +8229,7 @@ export class AgentSession {
 							this.#setModelWithProviderSessionReset(match);
 						} else {
 							this.agent.setModel(match);
+							this.#syncToolCallBatchCap(match);
 						}
 					}
 				}
@@ -8272,6 +8288,9 @@ export class AgentSession {
 			this.#scheduledHiddenNextTurnGeneration = previousScheduledHiddenNextTurnGeneration;
 			if (previousModel) {
 				this.agent.setModel(previousModel);
+				this.#syncToolCallBatchCap(previousModel);
+			} else {
+				this.#syncToolCallBatchCap(undefined);
 			}
 			this.#thinkingLevel = previousThinkingLevel;
 			this.agent.setThinkingLevel(toReasoningEffort(previousThinkingLevel));