diff --git a/packages/plugins/sandbox-providers/daytona/src/manifest.ts b/packages/plugins/sandbox-providers/daytona/src/manifest.ts
index d1ebbc70960..b1815acb511 100644
--- a/packages/plugins/sandbox-providers/daytona/src/manifest.ts
+++ b/packages/plugins/sandbox-providers/daytona/src/manifest.ts
@@ -24,6 +24,10 @@ const manifest: PaperclipPluginManifestV1 = {
       description:
         "Provisions Daytona sandboxes with configurable image or snapshot selection, startup timeouts, and lease reuse.",
       supportsReusableLeases: true,
+      isolation: {
+        kind: "container",
+        hardBoundary: true,
+      },
       configSchema: {
         type: "object",
         properties: {
diff --git a/packages/shared/src/types/plugin.ts b/packages/shared/src/types/plugin.ts
index 20ea2c2ecef..f4517816d06 100644
--- a/packages/shared/src/types/plugin.ts
+++ b/packages/shared/src/types/plugin.ts
@@ -144,6 +144,15 @@ export interface PluginEnvironmentDriverDeclaration {
    * behavior even if their config schema exposes a reuse-like setting.
    */
   supportsReusableLeases?: boolean;
+  /**
+   * Optional isolation claim used by the host to decide whether runtime secret
+   * material may be described as protected by a hard boundary. Omit this unless
+   * the driver actually runs work behind the declared boundary.
+   */
+  isolation?: {
+    kind: "separate_uid" | "namespace" | "container" | "vm" | "remote";
+    hardBoundary?: boolean;
+  };
   /** JSON Schema describing the driver's provider-specific configuration. */
   configSchema: JsonSchema;
 }
diff --git a/packages/shared/src/validators/plugin.ts b/packages/shared/src/validators/plugin.ts
index 3462d9d656d..17378793201 100644
--- a/packages/shared/src/validators/plugin.ts
+++ b/packages/shared/src/validators/plugin.ts
@@ -126,6 +126,10 @@ export const pluginEnvironmentDriverDeclarationSchema = z.object({
   displayName: z.string().min(1).max(100),
   description: z.string().max(500).optional(),
   supportsReusableLeases: z.boolean().optional(),
+  isolation: z.object({
+    kind: z.enum(["separate_uid", "namespace", "container", "vm", "remote"]),
+    hardBoundary: z.boolean().optional(),
+  }).optional(),
   configSchema: jsonSchemaSchema,
 });
 
diff --git a/server/src/__tests__/environment-runtime.test.ts b/server/src/__tests__/environment-runtime.test.ts
index 4ec89cbe1c6..d085e007e3b 100644
--- a/server/src/__tests__/environment-runtime.test.ts
+++ b/server/src/__tests__/environment-runtime.test.ts
@@ -277,6 +277,83 @@ describeEmbeddedPostgres("environmentRuntimeService", () => {
     };
   }
 
+  it("reports hard secret posture only for plugin-backed sandbox providers with a hard isolation claim", async () => {
+    await db.insert(plugins).values({
+      id: randomUUID(),
+      pluginKey: "acme.hard-sandbox-provider",
+      packageName: "@acme/hard-sandbox-provider",
+      version: "1.0.0",
+      apiVersion: 1,
+      categories: ["automation"],
+      manifestJson: {
+        id: "acme.hard-sandbox-provider",
+        apiVersion: 1,
+        version: "1.0.0",
+        displayName: "Hard Sandbox Provider",
+        description: "Test provider with a declared container boundary",
+        author: "Paperclip",
+        categories: ["automation"],
+        capabilities: ["environment.drivers.register"],
+        entrypoints: { worker: "dist/worker.js" },
+        environmentDrivers: [
+          {
+            driverKey: "hard-plugin",
+            kind: "sandbox_provider",
+            displayName: "Hard Plugin",
+            isolation: {
+              kind: "container",
+              hardBoundary: true,
+            },
+            configSchema: {
+              type: "object",
+              properties: {
+                image: { type: "string" },
+              },
+            },
+          },
+        ],
+      },
+      status: "ready",
+      installOrder: 1,
+      config: {},
+      createdAt: new Date(),
+      updatedAt: new Date(),
+    });
+    const { environment } = await seedEnvironment({
+      driver: "sandbox",
+      config: {
+        provider: "hard-plugin",
+        image: "paperclip:test",
+      },
+    });
+
+    await expect(runtime.resolveSecretPosture(environment)).resolves.toBe("hard");
+  });
+
+  it("reports soft secret posture for the built-in fake sandbox provider", async () => {
+    const { environment } = await seedEnvironment({
+      driver: "sandbox",
+      config: {
+        provider: "fake",
+        image: "ubuntu:24.04",
+      },
+    });
+
+    await expect(runtime.resolveSecretPosture(environment)).resolves.toBe("soft");
+  });
+
+  it("defaults unknown sandbox providers to soft secret posture", async () => {
+    const { environment } = await seedEnvironment({
+      driver: "sandbox",
+      config: {
+        provider: "missing-plugin",
+        image: "paperclip:test",
+      },
+    });
+
+    await expect(runtime.resolveSecretPosture(environment)).resolves.toBe("soft");
+  });
+
   async function seedReusablePluginSandboxLease() {
     const pluginId = randomUUID();
     const { companyId, agentId, environment: baseEnvironment, runId } = await seedEnvironment();
diff --git a/server/src/__tests__/heartbeat-project-env.test.ts b/server/src/__tests__/heartbeat-project-env.test.ts
index 3fd5112a324..abe1275f8a9 100644
--- a/server/src/__tests__/heartbeat-project-env.test.ts
+++ b/server/src/__tests__/heartbeat-project-env.test.ts
@@ -118,6 +118,7 @@ describe("resolveExecutionRunAdapterConfig", () => {
       "secret-project",
       "secret-routine",
     ]);
+    expect(result.secretManifest.every((entry) => entry.posture === "soft")).toBe(true);
     expect(JSON.stringify(result.secretManifest)).not.toContain("agent-only");
     expect(JSON.stringify(result.secretManifest)).not.toContain("environment-only");
     expect(JSON.stringify(result.secretManifest)).not.toContain("project-only");
@@ -132,6 +133,44 @@ describe("resolveExecutionRunAdapterConfig", () => {
     });
   });
 
+  it("labels runtime secret manifest entries with the selected environment posture", async () => {
+    const resolveAdapterConfigForRuntime = vi.fn().mockResolvedValue({
+      config: { env: { AGENT_SECRET: "resolved" } },
+      secretKeys: new Set(["AGENT_SECRET"]),
+      manifest: [
+        {
+          configPath: "env.AGENT_SECRET",
+          envKey: "AGENT_SECRET",
+          secretId: "secret-agent",
+          secretKey: "agent-secret",
+          version: 1,
+          provider: "local_encrypted",
+          posture: "soft",
+          outcome: "success",
+        },
+      ],
+    });
+
+    const result = await resolveExecutionRunAdapterConfig({
+      companyId: "company-1",
+      agentId: "agent-1",
+      executionRunConfig: { env: { AGENT_SECRET: { type: "secret_ref", secretId: "secret-agent" } } },
+      projectEnv: null,
+      secretPosture: "hard",
+      secretsSvc: {
+        resolveAdapterConfigForRuntime,
+        resolveEnvBindings: vi.fn(),
+      } as any,
+    });
+
+    expect(result.secretManifest).toEqual([
+      expect.objectContaining({
+        secretId: "secret-agent",
+        posture: "hard",
+      }),
+    ]);
+  });
+
   it("drops Paperclip runtime-owned env before resolving environment, agent, project, and routine overlays", async () => {
     const resolveAdapterConfigForRuntime = vi.fn(async (_companyId, config: Record<string, unknown>) => ({
       config: {
diff --git a/server/src/services/environment-runtime.ts b/server/src/services/environment-runtime.ts
index c5323085e5a..57c1c8fbf4f 100644
--- a/server/src/services/environment-runtime.ts
+++ b/server/src/services/environment-runtime.ts
@@ -8,6 +8,7 @@ import type {
   EnvironmentLeaseStatus,
   ExecutionWorkspace,
   PluginEnvironmentConfig,
+  PluginEnvironmentDriverDeclaration,
   SandboxEnvironmentConfig,
 } from "@paperclipai/shared";
 import type {
@@ -1113,6 +1114,53 @@ function sandboxConfigForLeaseMetadata(config: SandboxEnvironmentConfig): Record
   return { ...config };
 }
 
+export type RuntimeSecretPosture = "hard" | "soft";
+
+function pluginDriverReportsHardIsolation(
+  driver: PluginEnvironmentDriverDeclaration | null | undefined,
+): boolean {
+  return driver?.isolation?.hardBoundary === true;
+}
+
+async function resolvePluginEnvironmentHardIsolation(input: {
+  db: Db;
+  config: PluginEnvironmentConfig;
+}): Promise<boolean> {
+  const plugin = await pluginRegistryService(input.db).getByKey(input.config.pluginKey);
+  if (!plugin || plugin.status !== "ready") return false;
+  const driver = plugin.manifestJson.environmentDrivers?.find(
+    (candidate) => candidate.driverKey === input.config.driverKey,
+  );
+  return pluginDriverReportsHardIsolation(driver);
+}
+
+export async function resolveEnvironmentRuntimeSecretPosture(input: {
+  db: Db;
+  environment: Pick<Environment, "driver" | "config">;
+}): Promise<RuntimeSecretPosture> {
+  try {
+    const parsed = parseEnvironmentDriverConfig(input.environment as Environment);
+    if (parsed.driver === "sandbox") {
+      if (isBuiltinSandboxProvider(parsed.config.provider)) return "soft";
+      const resolved = await resolvePluginSandboxProviderDriverByKey({
+        db: input.db,
+        driverKey: parsed.config.provider,
+        requireRunning: false,
+      });
+      return pluginDriverReportsHardIsolation(resolved?.driver) ? "hard" : "soft";
+    }
+    if (parsed.driver === "plugin") {
+      return await resolvePluginEnvironmentHardIsolation({
+        db: input.db,
+        config: parsed.config,
+      }) ? "hard" : "soft";
+    }
+  } catch {
+    return "soft";
+  }
+  return "soft";
+}
+
 function tryParseCurrentPluginConfig(environment: Environment): PluginEnvironmentConfig | null {
   if (environment.driver !== "plugin") {
     return null;
@@ -1438,6 +1486,10 @@ export function environmentRuntimeService(
   return {
     getDriver,
 
+    async resolveSecretPosture(environment: Pick<Environment, "driver" | "config">): Promise<RuntimeSecretPosture> {
+      return await resolveEnvironmentRuntimeSecretPosture({ db, environment });
+    },
+
     async acquireRunLease(input: {
       companyId: string;
       environment: Environment;
diff --git a/server/src/services/heartbeat.ts b/server/src/services/heartbeat.ts
index 197b11d8c6e..e6071dbfb3d 100644
--- a/server/src/services/heartbeat.ts
+++ b/server/src/services/heartbeat.ts
@@ -192,7 +192,7 @@ import {
 import { extractSkillMentionIds, isUuidLike } from "@paperclipai/shared";
 import { environmentService } from "./environments.js";
 import { parseExecutionPolicyBootstrapEnv } from "./execution-policy-bootstrap.js";
-import { environmentRuntimeService } from "./environment-runtime.js";
+import { environmentRuntimeService, type RuntimeSecretPosture } from "./environment-runtime.js";
 import { skillVersionSelectionMap } from "./runtime-skill-selections.js";
 import { environmentRunOrchestrator } from "./environment-run-orchestrator.js";
 import { isUnsafeSessionWorkspaceCwd } from "./session-workspace-cwd.js";
@@ -504,6 +504,7 @@ export async function resolveExecutionRunAdapterConfig(input: {
   projectEnv: unknown;
   routineEnv?: unknown;
   secretsSvc: RuntimeConfigSecretResolver;
+  secretPosture?: RuntimeSecretPosture;
   trustPreset?: TrustPresetResolution;
   requiredScopedEnvBinding?: {
     keys: string[];
@@ -728,6 +729,7 @@ export async function resolveExecutionRunAdapterConfig(input: {
       secretKeys.add(key);
     }
   }
+  const secretPosture = input.secretPosture ?? "soft";
   return {
     resolvedConfig,
     secretKeys,
@@ -736,7 +738,7 @@ export async function resolveExecutionRunAdapterConfig(input: {
       ...(manifest ?? []),
       ...(projectEnvResolution.manifest ?? []),
       ...(routineEnvResolution.manifest ?? []),
-    ],
+    ].map((entry) => ({ ...entry, posture: secretPosture })),
   };
 }
 
@@ -8905,6 +8907,9 @@ export function heartbeatService(db: Db, options: HeartbeatServiceOptions = {})
       : selectedEnvironmentId
         ? await environmentsSvc.getById(selectedEnvironmentId)
         : null;
+    const runtimeSecretPosture = selectedEnvironmentForConfig
+      ? await environmentRuntime.resolveSecretPosture(selectedEnvironmentForConfig)
+      : "soft";
     const runScopedMentionedSkillKeys = await resolveRunScopedMentionedSkillKeys({
       db,
       companyId: agent.companyId,
@@ -8928,6 +8933,7 @@ export function heartbeatService(db: Db, options: HeartbeatServiceOptions = {})
       projectEnv: projectContext?.env ?? null,
       routineEnv: routineEnvContext.env,
       secretsSvc,
+      secretPosture: runtimeSecretPosture,
       trustPreset,
       requiredScopedEnvBinding: pushCapabilityPreflightRequired
         ? {
diff --git a/server/src/services/secrets.ts b/server/src/services/secrets.ts
index 8d8b7a418c3..dfa22c2914c 100644
--- a/server/src/services/secrets.ts
+++ b/server/src/services/secrets.ts
@@ -246,6 +246,7 @@ export type RuntimeSecretManifestEntry = {
   secretKey: string;
   version: number;
   provider: SecretProvider;
+  posture: "hard" | "soft";
   outcome: "success" | "failure";
   errorCode?: string | null;
 };
@@ -819,6 +820,7 @@ export function secretService(db: Db) {
           secretKey: secret.key,
           version: resolvedVersion,
           provider: providerId,
+          posture: "soft",
           outcome: "success",
         },
       };
@@ -864,6 +866,7 @@ export function secretService(db: Db) {
           secretKey: input.secret.key,
           version: 0,
           provider: input.secret.provider,
+          posture: "soft",
           outcome: "success",
         },
       };
@@ -915,6 +918,7 @@ export function secretService(db: Db) {
         secretKey: input.secret.key,
         version: 0,
         provider: input.secret.provider,
+        posture: "soft",
         outcome: "success",
       },
     };