From e3798ca91f23a69c6833443005ec8a252f292efc Mon Sep 17 00:00:00 2001
From: Dustin Spicuzza <dustin@virtualroadside.com>
Date: Tue, 11 Aug 2026 05:12:34 -0400
Subject: [PATCH] fix(coding-agent): inherit subagent session config (#7897)

---
 .../examples/extensions/subagent/README.md    |  2 ++
 .../examples/extensions/subagent/index.ts     | 24 ++++++++++++++++---
 2 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/packages/coding-agent/examples/extensions/subagent/README.md b/packages/coding-agent/examples/extensions/subagent/README.md
index f98b64586..9290342dc 100644
--- a/packages/coding-agent/examples/extensions/subagent/README.md
+++ b/packages/coding-agent/examples/extensions/subagent/README.md
@@ -137,6 +137,8 @@ model: claude-haiku-4-5
 System prompt for the agent goes here.
 ```
 
+When `model` is omitted, the subagent inherits the dispatching session's active model and thinking level.
+
 **Locations:**
 - `~/.pi/agent/agents/*.md` - User-level (always loaded)
 - `.pi/agents/*.md` - Project-level (only with `agentScope: "project"` or `"both"`)
diff --git a/packages/coding-agent/examples/extensions/subagent/index.ts b/packages/coding-agent/examples/extensions/subagent/index.ts
index 832dcc742..fa3b09e38 100644
--- a/packages/coding-agent/examples/extensions/subagent/index.ts
+++ b/packages/coding-agent/examples/extensions/subagent/index.ts
@@ -16,7 +16,7 @@ import { spawn } from "node:child_process";
 import * as fs from "node:fs";
 import * as os from "node:os";
 import * as path from "node:path";
-import type { AgentToolResult } from "@earendil-works/pi-agent-core";
+import type { AgentToolResult, ThinkingLevel } from "@earendil-works/pi-agent-core";
 import type { Message } from "@earendil-works/pi-ai";
 import { StringEnum } from "@earendil-works/pi-ai";
 import {
@@ -264,8 +264,14 @@ function getPiInvocation(args: string[]): { command: string; args: string[] } {
 
 type OnUpdateCallback = (partial: AgentToolResult<SubagentDetails>) => void;
 
+interface DispatchDefaults {
+	model?: string;
+	thinkingLevel?: ThinkingLevel;
+}
+
 async function runSingleAgent(
 	defaultCwd: string,
+	dispatchDefaults: DispatchDefaults,
 	agents: AgentConfig[],
 	agentName: string,
 	task: string,
@@ -292,7 +298,12 @@ async function runSingleAgent(
 	}
 
 	const args: string[] = ["--mode", "json", "-p", "--no-session"];
-	if (agent.model) args.push("--model", agent.model);
+	const inheritsDispatchConfig = !agent.model;
+	const model = agent.model ?? dispatchDefaults.model;
+	if (model) args.push("--model", model);
+	if (inheritsDispatchConfig && dispatchDefaults.thinkingLevel) {
+		args.push("--thinking", dispatchDefaults.thinkingLevel);
+	}
 	if (agent.tools && agent.tools.length > 0) args.push("--tools", agent.tools.join(","));
 
 	let tmpPromptDir: string | null = null;
@@ -306,7 +317,7 @@ async function runSingleAgent(
 		messages: [],
 		stderr: "",
 		usage: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0, cost: 0, contextTokens: 0, turns: 0 },
-		model: agent.model,
+		model,
 		step,
 	};
 
@@ -471,6 +482,10 @@ export default function (pi: ExtensionAPI) {
 
 		async execute(_toolCallId, params, signal, onUpdate, ctx) {
 			const agentScope: AgentScope = params.agentScope ?? "user";
+			const dispatchDefaults: DispatchDefaults = {
+				model: ctx.model ? `${ctx.model.provider}/${ctx.model.id}` : undefined,
+				thinkingLevel: ctx.thinkingLevel,
+			};
 			const discovery = discoverAgents(ctx.cwd, agentScope);
 			const agents = discovery.agents;
 			const confirmProjectAgents = params.confirmProjectAgents ?? true;
@@ -552,6 +567,7 @@ export default function (pi: ExtensionAPI) {
 
 					const result = await runSingleAgent(
 						ctx.cwd,
+						dispatchDefaults,
 						agents,
 						step.agent,
 						taskWithContext,
@@ -624,6 +640,7 @@ export default function (pi: ExtensionAPI) {
 				const results = await mapWithConcurrencyLimit(params.tasks, MAX_CONCURRENCY, async (t, index) => {
 					const result = await runSingleAgent(
 						ctx.cwd,
+						dispatchDefaults,
 						agents,
 						t.agent,
 						t.task,
@@ -666,6 +683,7 @@ export default function (pi: ExtensionAPI) {
 			if (params.agent && params.task) {
 				const result = await runSingleAgent(
 					ctx.cwd,
+					dispatchDefaults,
 					agents,
 					params.agent,
 					params.task,