diff --git a/docs/network-policy/explain-network-policy-to-agents.mdx b/docs/network-policy/explain-network-policy-to-agents.mdx
index 977c8b18472..a225323bae8 100644
--- a/docs/network-policy/explain-network-policy-to-agents.mdx
+++ b/docs/network-policy/explain-network-policy-to-agents.mdx
@@ -62,6 +62,7 @@ Each active preset includes a `verification` value:
 | `verified` | The registry lists the preset, and the gateway confirms enforcement. |
 | `registry-only` | The registry lists the preset, but the gateway does not enforce it. Treat the allowed hosts as unverified. |
 | `gateway-only` | The gateway enforces a preset that the registry does not list. |
+| `agent-base` | The gateway enforces this preset because it belongs to the agent's own base policy (`agents/<agent>/policy-additions.yaml`), not because the operator applied it. It is active, not drift. `policy add` is unnecessary and would record the preset as operator-applied. |
 | `gateway-unavailable` | NemoClaw could not probe the gateway. Treat the report as advisory until the gateway is reachable. |
 
 ## Classify a Failed Request
@@ -81,7 +82,7 @@ The classifier evaluates conditions in this order:
 
 Network-block error codes include `EHOSTUNREACH`, `ENETUNREACH`, `ENOTFOUND`, `ECONNREFUSED`, `ETIMEDOUT`, and `EAI_AGAIN`.
 A block code on a host from a `registry-only` or `gateway-unavailable` preset produces a low-confidence policy verdict.
-A block code on a host from a verified preset stays `unknown` because the gateway already confirmed enforcement.
+A block code on a host from a `verified`, `gateway-only`, or `agent-base` preset stays `unknown` with high confidence because the gateway confirmed enforcement.
 
 Each verdict includes `confidence` set to `high` or `low`.
 Low confidence means the agent must report multiple possibilities instead of treating one next step as authoritative.
diff --git a/src/lib/policy/agent-base-preset.test.ts b/src/lib/policy/agent-base-preset.test.ts
new file mode 100644
index 00000000000..f9eae5b385f
--- /dev/null
+++ b/src/lib/policy/agent-base-preset.test.ts
@@ -0,0 +1,69 @@
+// SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+import { randomUUID } from "node:crypto";
+import fs from "node:fs";
+import path from "node:path";
+
+import { afterEach, describe, expect, it, vi } from "vitest";
+
+import { AGENTS_DIR } from "../agent/defs";
+import * as registry from "../state/registry";
+import { isAgentBasePreset } from "./index";
+
+const tempAgentDirs: string[] = [];
+
+function createAgentFixture(policyAdditions?: string): string {
+  const agentName = `agent-base-preset-${randomUUID()}`;
+  const agentDir = path.join(AGENTS_DIR, agentName);
+  tempAgentDirs.push(agentDir);
+  fs.mkdirSync(agentDir, { recursive: true });
+  fs.writeFileSync(
+    path.join(agentDir, "manifest.yaml"),
+    `name: ${agentName}\ndisplay_name: Agent Base Preset Fixture\n`,
+  );
+  fs.writeFileSync(
+    path.join(agentDir, "policy-additions.yaml"),
+    policyAdditions ??
+      `version: 1
+network_policies:
+  github:
+    name: github
+    endpoints:
+      - host: api.github.com
+        port: 443
+        access: full
+    binaries:
+      - path: /usr/bin/git
+`,
+  );
+  return agentName;
+}
+
+afterEach(() => {
+  vi.restoreAllMocks();
+  for (const agentDir of tempAgentDirs.splice(0)) {
+    fs.rmSync(agentDir, { recursive: true, force: true });
+  }
+});
+
+describe("agent base preset detection", () => {
+  it("loads the recorded agent policy and distinguishes matching preset names (#9079)", () => {
+    const agent = createAgentFixture();
+    vi.spyOn(registry, "getSandbox").mockReturnValue({ name: "alpha", agent } as never);
+
+    expect(isAgentBasePreset("alpha", "github")).toBe(true);
+    expect(isAgentBasePreset("alpha", "slack")).toBe(false);
+  });
+
+  it("recognizes the Hermes base policy when its preset name also exists in the catalog (#9079)", () => {
+    const hermesPolicy = fs.readFileSync(
+      path.join(AGENTS_DIR, "hermes", "policy-additions.yaml"),
+      "utf8",
+    );
+    const agent = createAgentFixture(hermesPolicy);
+    vi.spyOn(registry, "getSandbox").mockReturnValue({ name: "hermes", agent } as never);
+
+    expect(isAgentBasePreset("hermes", "pypi")).toBe(true);
+  });
+});
diff --git a/src/lib/policy/context-builder.ts b/src/lib/policy/context-builder.ts
index 22511c3f9ae..7c2ba5e0013 100644
--- a/src/lib/policy/context-builder.ts
+++ b/src/lib/policy/context-builder.ts
@@ -6,6 +6,7 @@ import {
   getBaselineExclusionRuntimeStatus,
   getGatewayPresets,
   getPresetEndpoints,
+  isAgentBasePreset,
   listCustomPresets,
   listPresets,
   loadPresetForSandbox,
@@ -27,6 +28,7 @@ export type PolicyContextPresetVerification =
   | "verified"
   | "registry-only"
   | "gateway-only"
+  | "agent-base"
   | "gateway-unavailable";
 
 export interface PolicyContextPreset {
@@ -42,9 +44,9 @@ export interface PolicyContextPreset {
   source: "builtin" | "custom";
   /**
    * Source-of-truth state for whether this preset is enforced by the
-   * OpenShell gateway. `verified` and `gateway-only` are based on a live
-   * gateway probe; `registry-only` and `gateway-unavailable` indicate the
-   * agent cannot trust this preset as enforced policy.
+   * OpenShell gateway. `verified`, `gateway-only`, and `agent-base` are
+   * based on a live gateway probe. `registry-only` and `gateway-unavailable`
+   * indicate that the agent cannot trust this preset as enforced policy.
    */
   verification: PolicyContextPresetVerification;
 }
@@ -179,15 +181,28 @@ function partitionPresets(
   const unapplied: PolicyContextPreset[] = [];
   for (const info of builtin) {
     const isApplied = applied.has(info.name);
-    const verification = resolveVerification(info.name, isApplied, gatewayPresets);
-    const onGatewayOnly = !isApplied && verification === "gateway-only";
+    let verification = resolveVerification(info.name, isApplied, gatewayPresets);
+    // A gateway-only catalog preset whose name collides with an agent
+    // base-policy addition (e.g. Hermes `pypi`) is enforced by the agent's own
+    // base policy, not registry drift. Classify it as `agent-base` so it is not
+    // reported as drift and does not steer operators toward an unnecessary
+    // `policy add`.
+    // The apply path already prefers the agent-specific policy content, but it
+    // would record the preset as operator-applied (#9079). Sibling base additions
+    // with no catalog entry are never iterated here, so this only corrects the
+    // incidental name-collision case.
+    if (!isApplied && verification === "gateway-only" && isAgentBasePreset(sandboxName, info.name)) {
+      verification = "agent-base";
+    }
+    const enforcedNotApplied =
+      !isApplied && (verification === "gateway-only" || verification === "agent-base");
     const entry = presetEntry(
       info,
       "builtin",
       loadPresetForSandbox(sandboxName, info.name),
       verification,
     );
-    if (isApplied || onGatewayOnly) {
+    if (isApplied || enforcedNotApplied) {
       active.push(entry);
     } else {
       unapplied.push(entry);
@@ -321,10 +336,11 @@ function probeGatewayPresets(
  *   with a {@link PolicyContextPresetVerification} state: `verified` when
  *   the gateway snapshot agrees, `registry-only` when the gateway does
  *   not enforce the preset (drift), `gateway-only` when the gateway
- *   enforces something the registry does not list, or
- *   `gateway-unavailable` when no probe is available. Callers that
- *   require a trusted "is this host actually allowed?" answer must look
- *   at `verification === "verified"`; everything else is advisory.
+ *   enforces something the registry does not list, `agent-base` when the
+ *   gateway enforces an agent base-policy preset, or `gateway-unavailable`
+ *   when no probe is available. Callers that require a trusted "is this host
+ *   actually allowed?" answer must accept `verified`, `gateway-only`, and
+ *   `agent-base` as gateway-confirmed states.
  *
  * - Host stems are extracted by {@link hostStemsFromContent}, which
  *   redacts RFC1918, loopback, link-local, metadata, and internal-DNS
@@ -384,6 +400,8 @@ function verificationTag(verification: PolicyContextPresetVerification): string
       return "registry-only (gateway does not enforce)";
     case "gateway-only":
       return "gateway-only (not in local registry)";
+    case "agent-base":
+      return "agent-base (enforced by the agent's base policy; not user-applied; `policy add` is unnecessary)";
     case "gateway-unavailable":
       return "gateway-unavailable";
   }
@@ -507,7 +525,7 @@ export function renderPolicyContextMarkdown(ctx: PolicyContext): string {
   );
   lines.push("");
   lines.push(
-    "Preset status reflects registry vs gateway agreement and is one of `verified`, `registry-only`, `gateway-only`, or `gateway-unavailable`. Treat anything other than `verified` as advisory; an agent must not assume the gateway enforces the listed hosts.",
+    "Preset status reflects registry and gateway agreement. `verified`, `gateway-only`, and `agent-base` mean the gateway confirms enforcement. `agent-base` identifies a preset from the agent's base policy rather than a user-applied preset. It is active, not drift, and does not need `policy add`. Treat `registry-only` and `gateway-unavailable` as advisory because the gateway has not confirmed the listed hosts.",
   );
   lines.push("");
   lines.push(`Generated at ${ctx.generatedAt}.`);
diff --git a/src/lib/policy/context.test.ts b/src/lib/policy/context.test.ts
index 0518b4f4812..02120c14319 100644
--- a/src/lib/policy/context.test.ts
+++ b/src/lib/policy/context.test.ts
@@ -13,6 +13,7 @@ vi.mock(".", () => ({
   getBaselineExclusionRuntimeStatus: vi.fn(() => "excluded"),
   getPresetEndpoints: vi.fn(),
   getGatewayPresets: vi.fn(() => null),
+  isAgentBasePreset: vi.fn(() => false),
   listCustomPresets: vi.fn(),
   listPresets: vi.fn(),
   loadPreset: vi.fn(),
@@ -103,6 +104,8 @@ function resetMocks() {
   vi.mocked(policies.getPresetEndpoints).mockReset();
   vi.mocked(policies.getGatewayPresets).mockReset();
   vi.mocked(policies.getGatewayPresets).mockReturnValue(null);
+  vi.mocked(policies.isAgentBasePreset).mockReset();
+  vi.mocked(policies.isAgentBasePreset).mockReturnValue(false);
   vi.mocked(registry.getBaselineExclusions).mockReset();
   vi.mocked(registry.getBaselineExclusions).mockReturnValue([]);
   vi.mocked(policies.getBaselineExclusionRuntimeStatus).mockReset();
@@ -170,6 +173,43 @@ describe("buildPolicyContext", () => {
     expect(ctx.knownUnappliedPresets.some((p) => p.name === "github")).toBe(false);
   });
 
+  it("classifies a gateway-enforced agent-base preset as `agent-base`, not gateway-only drift (#9079)", () => {
+    resetMocks();
+    mockBuiltinPresets();
+    stubTier();
+    // Neither preset applied by the user; both enforced by the gateway. Only
+    // `github` is an agent base-policy addition. The other must stay
+    // gateway-only so genuine drift is still reported.
+    stubRegistry({ policies: [], policyTier: "restricted" });
+    vi.mocked(policies.isAgentBasePreset).mockImplementation(
+      (_sandboxName: string, name: string) => name === "github",
+    );
+
+    const ctx = buildPolicyContext(SANDBOX, { gatewayPresets: ["slack", "github"] });
+
+    const github = ctx.activePresets.find((p) => p.name === "github");
+    const slack = ctx.activePresets.find((p) => p.name === "slack");
+    expect(github?.verification).toBe("agent-base");
+    expect(slack?.verification).toBe("gateway-only");
+    // Agent-base preset is active (enforced), never suggested for `policy add`.
+    expect(ctx.knownUnappliedPresets.some((p) => p.name === "github")).toBe(false);
+  });
+
+  it("does not reclassify an applied preset as agent-base even when the agent defines it (#9079)", () => {
+    resetMocks();
+    mockBuiltinPresets();
+    stubTier();
+    // `github` is both user-applied and an agent base addition; the user
+    // intent (applied + enforced) must remain `verified`, not `agent-base`.
+    stubRegistry({ policies: ["github"], policyTier: "restricted" });
+    vi.mocked(policies.isAgentBasePreset).mockReturnValue(true);
+
+    const ctx = buildPolicyContext(SANDBOX, { gatewayPresets: ["github"] });
+
+    const github = ctx.activePresets.find((p) => p.name === "github");
+    expect(github?.verification).toBe("verified");
+  });
+
   it("redacts internal hostnames and IP ranges from allowedHostCategories and counts the drop", () => {
     resetMocks();
     mockBuiltinPresets();
@@ -437,7 +477,57 @@ describe("renderPolicyContextMarkdown", () => {
     expect(md).not.toMatch(/network_policies:/);
   });
 
-  it("renders the verification status alongside each active preset", () => {
+  it.each([
+    {
+      status: "verified",
+      applied: ["slack"],
+      gatewayPresets: ["slack"],
+      agentBase: false,
+    },
+    {
+      status: "registry-only",
+      applied: ["slack"],
+      gatewayPresets: [],
+      agentBase: false,
+    },
+    {
+      status: "gateway-only",
+      applied: [],
+      gatewayPresets: ["slack"],
+      agentBase: false,
+    },
+    {
+      status: "agent-base",
+      applied: [],
+      gatewayPresets: ["slack"],
+      agentBase: true,
+    },
+    {
+      status: "gateway-unavailable",
+      applied: ["slack"],
+      gatewayPresets: null,
+      agentBase: false,
+    },
+  ])("renders the $status verification status (#9079)", ({
+    status,
+    applied,
+    gatewayPresets,
+    agentBase,
+  }) => {
+    resetMocks();
+    mockBuiltinPresets();
+    stubTier();
+    stubRegistry({ policies: applied, policyTier: "balanced" });
+    vi.mocked(policies.isAgentBasePreset).mockReturnValue(agentBase);
+
+    const md = renderPolicyContextMarkdown(
+      buildPolicyContext(SANDBOX, { gatewayPresets }),
+    );
+
+    expect(md).toContain(`status: ${status}`);
+  });
+
+  it("states which verification statuses confirm gateway enforcement (#9079)", () => {
     resetMocks();
     mockBuiltinPresets();
     stubTier();
@@ -446,7 +536,13 @@ describe("renderPolicyContextMarkdown", () => {
     const md = renderPolicyContextMarkdown(
       buildPolicyContext(SANDBOX, { gatewayPresets: ["slack"] }),
     );
-    expect(md).toContain("status: verified");
+
+    expect(md).toContain(
+      "`verified`, `gateway-only`, and `agent-base` mean the gateway confirms enforcement",
+    );
+    expect(md).toContain(
+      "Treat `registry-only` and `gateway-unavailable` as advisory because the gateway has not confirmed the listed hosts",
+    );
   });
 
   it("discloses excluded baseline entries and their support impact (#7194)", () => {
diff --git a/src/lib/policy/failure-classifier.test.ts b/src/lib/policy/failure-classifier.test.ts
index afce73624e6..56f818e26ce 100644
--- a/src/lib/policy/failure-classifier.test.ts
+++ b/src/lib/policy/failure-classifier.test.ts
@@ -13,6 +13,7 @@ vi.mock(".", () => ({
   getPresetEndpoints: vi.fn(),
   getGatewayPresets: vi.fn(() => null),
   getSandboxBaselineEntryDigest: vi.fn(() => null),
+  isAgentBasePreset: vi.fn(() => false),
   listCustomPresets: vi.fn(),
   listPresets: vi.fn(),
   loadPreset: vi.fn(),
@@ -103,6 +104,8 @@ function resetMocks() {
   vi.mocked(policies.getPresetEndpoints).mockReset();
   vi.mocked(policies.getGatewayPresets).mockReset();
   vi.mocked(policies.getGatewayPresets).mockReturnValue(null);
+  vi.mocked(policies.isAgentBasePreset).mockReset();
+  vi.mocked(policies.isAgentBasePreset).mockReturnValue(false);
   vi.mocked(getTier).mockReset();
 }
 
@@ -299,6 +302,28 @@ describe("classifyAccessFailure", () => {
     expect(result.reason).toContain("upstream");
   });
 
+  it("treats an agent-base preset host hitting a network-block code as high-confidence upstream-unknown (#9079)", () => {
+    resetMocks();
+    mockBuiltinPresets();
+    stubTier();
+    // `slack` is enforced by the gateway via the agent base policy, not
+    // user-applied. Verification resolves to `agent-base`, which is enforced,
+    // so a block code is upstream (like `verified`), not a policy denial.
+    stubRegistry({ policies: [], policyTier: "restricted" });
+    vi.mocked(policies.isAgentBasePreset).mockReturnValue(true);
+
+    const result = classifyAccessFailure({
+      sandboxName: SANDBOX,
+      host: "api.slack.com",
+      error: { code: "EHOSTUNREACH" },
+      gatewayPresets: ["slack"],
+    });
+
+    expect(result.kind).toBe("unknown");
+    expect(result.matchedPreset).toBe("slack");
+    expect(result.confidence).toBe("high");
+  });
+
   it.each([
     "EHOSTUNREACH",
     "ENETUNREACH",
diff --git a/src/lib/policy/failure-classifier.ts b/src/lib/policy/failure-classifier.ts
index 4ea8721b3f6..e8e26efa8ef 100644
--- a/src/lib/policy/failure-classifier.ts
+++ b/src/lib/policy/failure-classifier.ts
@@ -93,7 +93,11 @@ function findMatchingPreset(
 }
 
 function isVerified(preset: PolicyContextPreset): boolean {
-  return preset.verification === "verified" || preset.verification === "gateway-only";
+  return (
+    preset.verification === "verified" ||
+    preset.verification === "gateway-only" ||
+    preset.verification === "agent-base"
+  );
 }
 
 function verificationNote(preset: PolicyContextPreset): string {
diff --git a/src/lib/policy/index.ts b/src/lib/policy/index.ts
index ddb1fdb6126..7f33f2c1d3c 100644
--- a/src/lib/policy/index.ts
+++ b/src/lib/policy/index.ts
@@ -297,6 +297,22 @@ function loadAgentPresetContent(
   }
 }
 
+/**
+ * True when `presetName` is supplied by the sandbox agent's base policy
+ * (`agents/<agent>/policy-additions.yaml`) rather than only by the built-in
+ * catalog. Used to distinguish an agent base-policy entry that the gateway
+ * enforces (for example, Hermes `pypi`) from genuine registry drift.
+ * `policy explain` can then avoid an unnecessary `policy add`, which would
+ * record the preset as operator-applied even though the apply path already
+ * prefers the agent-specific policy content (#9079). Best-effort: any load
+ * failure resolves to `false`, preserving the pre-existing gateway-only
+ * classification.
+ */
+function isAgentBasePreset(sandboxName: string, presetName: string): boolean {
+  const builtinPresetContent = loadCentralPreset(presetName);
+  return loadAgentPresetContent(sandboxName, presetName, builtinPresetContent ?? "") !== null;
+}
+
 function loadPresetForSandbox(sandboxName: string, presetName: string): string | null {
   let sandboxAgent: string | null = null;
   try {
@@ -2682,6 +2698,7 @@ export {
   getPresetValidationWarning,
   getSandboxBaselineEntry,
   getSandboxBaselineEntryDigest,
+  isAgentBasePreset,
   isMessagingChannelPolicyPreset,
   listCustomPresets,
   listPresets,