diff --git a/extensions/subagents/index.ts b/extensions/subagents/index.ts
index ff75e9bd..8483da37 100644
--- a/extensions/subagents/index.ts
+++ b/extensions/subagents/index.ts
@@ -889,8 +889,14 @@ export default function (
     // report it once. Never fatal: the rest still loaded. Non-UI modes receive
     // stderr rather than a model-context message.
     const notice = formatAgentTypeDiagnostics(agentTypeDiagnostics);
-    if (notice && ctx.hasUI) ctx.ui.notify(notice, "warning");
-    else if (notice) process.stderr.write(`${notice}\n`);
+    if (notice && ctx.hasUI) {
+      const severity = agentTypeDiagnostics.some(
+        (diagnostic) => diagnostic.severity !== "info",
+      )
+        ? "warning"
+        : "info";
+      ctx.ui.notify(notice, severity);
+    } else if (notice) process.stderr.write(`${notice}\n`);
   });
 
   // A new explicit request starts a fresh unread window: previously finished
diff --git a/extensions/subagents/src/agent-types.ts b/extensions/subagents/src/agent-types.ts
index 7c52202a..299016c1 100644
--- a/extensions/subagents/src/agent-types.ts
+++ b/extensions/subagents/src/agent-types.ts
@@ -221,9 +221,11 @@ export function roleModelForAgentType(
 }
 
 export interface AgentTypeDiagnostic {
-  /** File the problem came from, or the directory for a scan failure. */
+  /** File the diagnostic came from, or the directory for a scan failure. */
   readonly source: string;
   readonly message: string;
+  /** Omitted diagnostics are warnings; valid overrides are informational. */
+  readonly severity?: "info" | "warning";
 }
 
 function isRecord(value: unknown): value is Record<string, unknown> {
@@ -530,6 +532,7 @@ export function loadAgentTypes(options: LoadAgentTypesOptions) {
         diagnostics.push({
           source: agentType.source,
           message: `overrides the agent type of the same name from ${shadowed.source}`,
+          severity: "info",
         });
       }
       agentTypes.set(agentType.name, agentType);
@@ -539,14 +542,22 @@ export function loadAgentTypes(options: LoadAgentTypesOptions) {
   return { agentTypes, diagnostics };
 }
 
-/** One-line-per-problem notice, or undefined when everything loaded cleanly. */
+/** One-line-per-diagnostic notice, or undefined when everything loaded cleanly. */
 export function formatAgentTypeDiagnostics(
   diagnostics: readonly AgentTypeDiagnostic[],
 ) {
   if (diagnostics.length === 0) return undefined;
+  const problemCount = diagnostics.filter(
+    (entry) => entry.severity !== "info",
+  ).length;
+  const informationalCount = diagnostics.length - problemCount;
   return sanitizeTerminalText(
     [
-      `Agent types: ${diagnostics.length} problem${diagnostics.length === 1 ? "" : "s"}.`,
+      `Agent types: ${problemCount} problem${problemCount === 1 ? "" : "s"}${
+        informationalCount > 0
+          ? `, ${informationalCount} informational notice${informationalCount === 1 ? "" : "s"}`
+          : ""
+      }.`,
       ...diagnostics.map((entry) => `- ${entry.source}: ${entry.message}`),
     ].join("\n"),
   );
diff --git a/tests/extensions/subagents/agent-types.test.ts b/tests/extensions/subagents/agent-types.test.ts
index 38669c3e..ef06185e 100644
--- a/tests/extensions/subagents/agent-types.test.ts
+++ b/tests/extensions/subagents/agent-types.test.ts
@@ -218,6 +218,10 @@ test("an unrecognized tool name is reported but still applied", () => {
     result.diagnostics[0]?.message ?? "",
     /unrecognized tool "gerp"/,
   );
+  assert.match(
+    formatAgentTypeDiagnostics(result.diagnostics) ?? "",
+    /1 problem/,
+  );
 });
 
 test("an over-long body is rejected rather than silently truncated", () => {
@@ -286,7 +290,7 @@ test("a project agent type overrides the global one of the same name", async ()
       global: { "explorer.md": BUILT_IN_EXPLORER },
       project: {
         "explorer.md":
-          "---\nname: explorer\ndescription: Project override.\ntools: [read]\n---\nProject body.",
+          "---\nname: explorer\ndescription: Project override.\ntools: [read]\nmodel: project/model\nreasoning_effort: high\n---\nProject body.",
       },
     });
 
@@ -299,10 +303,21 @@ test("a project agent type overrides the global one of the same name", async ()
     assert.equal(agentTypes.size, 4);
     assert.deepEqual(agentTypes.get("explorer")?.tools, ["read"]);
     assert.equal(agentTypes.get("explorer")?.planningCompatible, undefined);
+    assert.equal(agentTypes.get("explorer")?.model, "project/model");
+    assert.equal(agentTypes.get("explorer")?.reasoningEffort, "high");
+    assert.deepEqual(
+      diagnostics.map((entry) =>
+        "severity" in entry ? entry.severity : undefined,
+      ),
+      ["info", "info"],
+    );
     // Global replaces the built-in, then the trusted project replaces global.
     const messages = diagnostics.map((entry) => entry.message).join("\n");
     assert.match(messages, /from built-in:explorer/);
     assert.match(messages, /from .*agent[\\/]agents[\\/]explorer\.md/);
+    const notice = formatAgentTypeDiagnostics(diagnostics) ?? "";
+    assert.match(notice, /0 problems, 2 informational notices/);
+    assert.match(notice, /explorer\.md: overrides the agent type/);
   });
 });
 
@@ -359,6 +374,10 @@ test("an unreadable precedence layer blocks every broader fallback", async () =>
       loaded.diagnostics.map((entry) => entry.message).join("\n"),
       /all lower-precedence definitions are blocked/,
     );
+    assert.match(
+      formatAgentTypeDiagnostics(loaded.diagnostics) ?? "",
+      /1 problem/,
+    );
   });
 });
 
@@ -493,6 +512,10 @@ Do not write.
       loaded.diagnostics.map((entry) => entry.message).join("\n"),
       /blocks fallback to built-in:implementer/,
     );
+    assert.match(
+      formatAgentTypeDiagnostics(loaded.diagnostics) ?? "",
+      /2 problems/,
+    );
   });
 });
 
diff --git a/tests/extensions/subagents/index.test.ts b/tests/extensions/subagents/index.test.ts
index b1a892c3..b3365579 100644
--- a/tests/extensions/subagents/index.test.ts
+++ b/tests/extensions/subagents/index.test.ts
@@ -862,6 +862,118 @@ async function withTempDir(run: (directory: string) => Promise<void>) {
   }
 }
 
+async function readAgentTypeStartupNotices(cwd: string) {
+  const notices: Array<{ message: string; severity: string }> = [];
+  let sessionStart:
+    | ((event: unknown, ctx: ExtensionContext) => unknown)
+    | undefined;
+  let sessionShutdown: (() => unknown) | undefined;
+  const pi = {
+    on(event: string, handler: unknown) {
+      if (event === "session_start") {
+        sessionStart = handler as typeof sessionStart;
+      }
+      if (event === "session_shutdown") {
+        sessionShutdown = handler as typeof sessionShutdown;
+      }
+    },
+    events: { on() {} },
+    registerTool() {},
+    getActiveTools: () => [],
+    setActiveTools() {},
+    registerMessageRenderer() {},
+    registerEntryRenderer() {},
+    registerCommand() {},
+  } as unknown as ExtensionAPI;
+
+  subagents(pi);
+  assert.ok(sessionStart);
+  await sessionStart({}, {
+    cwd,
+    hasUI: true,
+    isProjectTrusted: () => true,
+    sessionManager: emptySessionManager,
+    ui: {
+      notify(message: string, severity: string) {
+        notices.push({ message, severity });
+      },
+      setStatus() {},
+      setWidget() {},
+    },
+  } as unknown as ExtensionContext);
+  await sessionShutdown?.();
+  return notices;
+}
+
+test("session start reports valid built-in and project overrides as info", async () => {
+  await withTempDir(async (cwd) => {
+    const globalDir = path.join(cwd, "agent", "agents");
+    const projectDir = path.join(cwd, ".pi", "agents");
+    await mkdir(globalDir, { recursive: true });
+    await mkdir(projectDir, { recursive: true });
+    await writeFile(
+      path.join(globalDir, "explorer.md"),
+      "---\nname: explorer\ndescription: Global override.\ntools: [read]\n---\nGlobal.",
+    );
+    await writeFile(
+      path.join(projectDir, "explorer.md"),
+      "---\nname: explorer\ndescription: Project override.\ntools: [read]\n---\nProject.",
+    );
+
+    const notices = await readAgentTypeStartupNotices(cwd);
+    assert.equal(notices.length, 1);
+    assert.equal(notices[0]?.severity, "info");
+    assert.match(
+      notices[0]?.message ?? "",
+      /0 problems, 2 informational notices/,
+    );
+    assert.match(notices[0]?.message ?? "", /from built-in:explorer/);
+    assert.match(
+      notices[0]?.message ?? "",
+      /\.pi[\\/]agents[\\/]explorer\.md: overrides the agent type/,
+    );
+  });
+});
+
+test("session start keeps mixed override and error diagnostics at warning", async () => {
+  await withTempDir(async (cwd) => {
+    const globalDir = path.join(cwd, "agent", "agents");
+    const projectDir = path.join(cwd, ".pi", "agents");
+    await mkdir(globalDir, { recursive: true });
+    await mkdir(projectDir, { recursive: true });
+    await writeFile(
+      path.join(globalDir, "explorer.md"),
+      "---\nname: explorer\ndescription: Global override.\ntools: [read]\n---\nGlobal.",
+    );
+    await writeFile(
+      path.join(globalDir, "unknown-tool.md"),
+      "---\nname: unknown-tool\ndescription: Unknown tool.\ntools: [read, gerp]\n---\nBody.",
+    );
+    await writeFile(
+      path.join(projectDir, "explorer.md"),
+      "---\nname: explorer\ndescription: Project override.\ntools: [read]\n---\nProject.",
+    );
+    await writeFile(
+      path.join(projectDir, "implementer.md"),
+      "---\nname: implementer\ndescription: Malformed override.\ntool: [read]\n---\nBody.",
+    );
+
+    const notices = await readAgentTypeStartupNotices(cwd);
+    assert.equal(notices.length, 1);
+    assert.equal(notices[0]?.severity, "warning");
+    assert.match(
+      notices[0]?.message ?? "",
+      /3 problems, 2 informational notices/,
+    );
+    assert.match(notices[0]?.message ?? "", /unrecognized tool "gerp"/);
+    assert.match(
+      notices[0]?.message ?? "",
+      /blocks fallback to built-in:implementer/,
+    );
+    assert.match(notices[0]?.message ?? "", /from built-in:explorer/);
+  });
+});
+
 test("session_start re-registers agent types for its cwd and live trust decision", async () => {
   await withTempDir(async (cwd) => {
     await mkdir(path.join(cwd, ".pi", "agents"), { recursive: true });