diff --git a/src/security/audit-rosterless.test.ts b/src/security/audit-rosterless.test.ts
index b4fbdd039c6d..890a15c4bbc0 100644
--- a/src/security/audit-rosterless.test.ts
+++ b/src/security/audit-rosterless.test.ts
@@ -102,6 +102,26 @@ describe("security audit rosterless configs", () => {
     );
   });
 
+  it("accepts a fresh-install sole-agent roster without a default marker", async () => {
+    const { stateDir, workspaceDir } = makeAuditPaths("fresh-install-roster");
+
+    // `openclaw onboard` and `agents add` write markerless entries; runtime
+    // resolves the sole agent as default, so the audit must not warn.
+    const report = await runSecurityAuditCore({
+      config: { agents: { entries: { main: {} } } } as never,
+      stateDir,
+      configPath: path.join(stateDir, "openclaw.json"),
+      workspaceDir,
+      env: {},
+      includeFilesystem: true,
+      includeChannelSecurity: false,
+    });
+
+    expect(report.findings).not.toContainEqual(
+      expect.objectContaining({ checkId: "config.agent_roster.invalid_default_count" }),
+    );
+  });
+
   it.each([
     {
       label: "an explicitly empty roster",
diff --git a/src/security/audit.ts b/src/security/audit.ts
index 47dd4bfa5e1c..1ec4ca7d5b69 100644
--- a/src/security/audit.ts
+++ b/src/security/audit.ts
@@ -4,7 +4,11 @@ import { redactSensitiveUrlLikeString } from "@openclaw/net-policy/redact-sensit
 import { asNullableRecord } from "@openclaw/normalization-core/record-coerce";
 import { normalizeOptionalString } from "@openclaw/normalization-core/string-coerce";
 import { normalizeStringEntries } from "@openclaw/normalization-core/string-normalization";
-import { hasAgentRosterProperty, listAgentEntries } from "../agents/agent-scope-config.js";
+import {
+  hasAgentRosterProperty,
+  listAgentEntries,
+  tryResolveLegacyCompatibilityAgentId,
+} from "../agents/agent-scope-config.js";
 import { tryResolveDefaultAgentId } from "../agents/agent-scope.js";
 import { resolveExecDefaults } from "../agents/exec-defaults.js";
 import { resolveSandboxConfigForAgent } from "../agents/sandbox/config.js";
@@ -955,8 +959,14 @@ function collectAgentRosterFindings(cfg: OpenClawConfig): SecurityAuditFinding[]
     return [];
   }
   const defaultCount = agents.filter((agent) => agent?.default === true).length;
-  const expectedDefaultCount = cfg.agents?.ownership === "explicit" ? 0 : 1;
-  if (defaultCount === expectedDefaultCount) {
+  const explicitOwnership = cfg.agents?.ownership === "explicit";
+  // Mirror runtime default resolution: explicit fleets are ownerless by design,
+  // otherwise the roster is valid exactly when the canonical resolver finds an
+  // owner (sole agent, one legacy marker, or a retained migration owner).
+  const resolvable = explicitOwnership
+    ? defaultCount === 0
+    : tryResolveLegacyCompatibilityAgentId(cfg) !== undefined;
+  if (resolvable) {
     return [];
   }
   return [
@@ -964,10 +974,9 @@ function collectAgentRosterFindings(cfg: OpenClawConfig): SecurityAuditFinding[]
       checkId: "config.agent_roster.invalid_default_count",
       severity: "warn",
       title: "Agent roster has an invalid default selection",
-      detail:
-        expectedDefaultCount === 0
-          ? `Expected no agents.entries default=true entries with agents.ownership=explicit, found ${defaultCount}.`
-          : `Expected exactly one agents.entries default=true entry, found ${defaultCount}.`,
+      detail: explicitOwnership
+        ? `Expected no agents.entries default=true entries with agents.ownership=explicit, found ${defaultCount}.`
+        : `Expected a resolvable default agent (sole entry, one default=true marker, or agents.ownership=explicit); found ${defaultCount} default markers across ${agents.length} configured agents.`,
       remediation: "Run `openclaw doctor --fix` to repair the authored agent roster.",
     },
   ];