diff --git a/app/Support/EnvAuditor.php b/app/Support/EnvAuditor.php
index 67de4aa82..95e1a5d0a 100644
--- a/app/Support/EnvAuditor.php
+++ b/app/Support/EnvAuditor.php
@@ -2,6 +2,10 @@
 
 namespace App\Support;
 
+use Illuminate\Support\Env;
+use InvalidArgumentException;
+use JsonException;
+
 /**
  * Scans the process environment against the DW_* contract from
  * config/dw-contract.php and produces a structured report.
@@ -139,4 +143,38 @@ public static function env(string $name, ?string $legacy, mixed $default = null)
 
         return $legacy === null ? $default : env($legacy, $default);
     }
+
+    /**
+     * Resolve a policy object without converting malformed JSON into defaults.
+     * Read the raw repository value so Laravel's special null/false/empty env
+     * conversions cannot hide an explicitly supplied invalid JSON value.
+     *
+     * @return array<array-key, mixed>
+     */
+    public static function jsonObject(string $name, ?string $legacy): array
+    {
+        $repository = Env::getRepository();
+        $raw = $repository->get($name);
+        if ($raw === null && $legacy !== null) {
+            $raw = $repository->get($legacy);
+            if ($raw !== null) {
+                $name = $legacy;
+            }
+        }
+        if ($raw === null) {
+            return [];
+        }
+
+        try {
+            $value = json_decode($raw, true, 512, JSON_THROW_ON_ERROR);
+        } catch (JsonException) {
+            throw new InvalidArgumentException($name.' must contain a valid JSON object.');
+        }
+
+        if (! is_array($value) || ! str_starts_with(ltrim($raw), '{')) {
+            throw new InvalidArgumentException($name.' must contain a valid JSON object.');
+        }
+
+        return $value;
+    }
 }
diff --git a/config/server.php b/config/server.php
index 8cda72d93..9e6c0d793 100644
--- a/config/server.php
+++ b/config/server.php
@@ -364,14 +364,10 @@
                 null,
             ),
         ],
-        'queue_overrides' => json_decode(
-            (string) EnvAuditor::env(
-                'DW_TASK_QUEUE_ADMISSION_OVERRIDES',
-                'WORKFLOW_SERVER_TASK_QUEUE_ADMISSION_OVERRIDES',
-                '{}',
-            ),
-            true,
-        ) ?: [],
+        'queue_overrides' => EnvAuditor::jsonObject(
+            'DW_TASK_QUEUE_ADMISSION_OVERRIDES',
+            'WORKFLOW_SERVER_TASK_QUEUE_ADMISSION_OVERRIDES',
+        ),
         'lock_ttl_seconds' => 5,
         'lock_wait_seconds' => 1,
     ],
@@ -409,14 +405,10 @@
             'WORKFLOW_SERVER_NAMESPACE_HARD_MAX_CONCURRENT_REQUESTS',
             null,
         ),
-        'overrides' => json_decode(
-            (string) EnvAuditor::env(
-                'DW_NAMESPACE_ADMISSION_OVERRIDES',
-                'WORKFLOW_SERVER_NAMESPACE_ADMISSION_OVERRIDES',
-                '{}',
-            ),
-            true,
-        ) ?: [],
+        'overrides' => EnvAuditor::jsonObject(
+            'DW_NAMESPACE_ADMISSION_OVERRIDES',
+            'WORKFLOW_SERVER_NAMESPACE_ADMISSION_OVERRIDES',
+        ),
         'lock_ttl_seconds' => 5,
         'lock_wait_seconds' => 1,
         'request_lease_ttl_seconds' => 120,
@@ -437,29 +429,17 @@
     */
 
     'namespace_durable_state' => [
-        'limits' => json_decode(
-            (string) EnvAuditor::env(
-                'DW_NAMESPACE_DURABLE_LIMITS',
-                'WORKFLOW_SERVER_NAMESPACE_DURABLE_LIMITS',
-                '{}',
-            ),
-            true,
+        'limits' => EnvAuditor::jsonObject(
+            'DW_NAMESPACE_DURABLE_LIMITS',
+            'WORKFLOW_SERVER_NAMESPACE_DURABLE_LIMITS',
         ),
-        'hard_limits' => json_decode(
-            (string) EnvAuditor::env(
-                'DW_NAMESPACE_DURABLE_HARD_LIMITS',
-                'WORKFLOW_SERVER_NAMESPACE_DURABLE_HARD_LIMITS',
-                '{}',
-            ),
-            true,
+        'hard_limits' => EnvAuditor::jsonObject(
+            'DW_NAMESPACE_DURABLE_HARD_LIMITS',
+            'WORKFLOW_SERVER_NAMESPACE_DURABLE_HARD_LIMITS',
         ),
-        'overrides' => json_decode(
-            (string) EnvAuditor::env(
-                'DW_NAMESPACE_DURABLE_OVERRIDES',
-                'WORKFLOW_SERVER_NAMESPACE_DURABLE_OVERRIDES',
-                '{}',
-            ),
-            true,
+        'overrides' => EnvAuditor::jsonObject(
+            'DW_NAMESPACE_DURABLE_OVERRIDES',
+            'WORKFLOW_SERVER_NAMESPACE_DURABLE_OVERRIDES',
         ),
     ],
 
@@ -540,13 +520,9 @@
             'WORKFLOW_SERVER_EXTERNAL_PAYLOAD_HARD_MAX_OBJECTS_PER_NAMESPACE',
             null,
         ),
-        'namespace_overrides' => json_decode(
-            (string) EnvAuditor::env(
-                'DW_EXTERNAL_PAYLOAD_NAMESPACE_OVERRIDES',
-                'WORKFLOW_SERVER_EXTERNAL_PAYLOAD_NAMESPACE_OVERRIDES',
-                '{}',
-            ),
-            true,
+        'namespace_overrides' => EnvAuditor::jsonObject(
+            'DW_EXTERNAL_PAYLOAD_NAMESPACE_OVERRIDES',
+            'WORKFLOW_SERVER_EXTERNAL_PAYLOAD_NAMESPACE_OVERRIDES',
         ),
     ],
 
diff --git a/docs/server-reference.md b/docs/server-reference.md
index d57afc063..fdf7d4b1f 100644
--- a/docs/server-reference.md
+++ b/docs/server-reference.md
@@ -1741,6 +1741,16 @@ fine; renames require a major bump with the old name alias-honored for
 one major. Set `DW_ENV_AUDIT_STRICT=1` to fail container boot when the
 audit finds drift.
 
+Admission policy values must be JSON objects. The queue admission, namespace
+request, namespace durable-state and external-payload namespace maps reject
+malformed JSON, arrays, scalars and explicit `null` during configuration loading
+and `config:cache`, regardless of `DW_ENV_AUDIT_STRICT`. An omitted setting or
+`{}` retains its empty-map default. A supplied `DW_*` value takes precedence
+over its legacy alias even when it is invalid; an invalid primary does not
+silently select the legacy policy. The error names the selected variable
+without printing its value. Correct that variable, rebuild cached configuration
+and restart every role that uses it.
+
 #### Environment variable reference
 
 The full table below is generated from `config/dw-contract.php` and lists
diff --git a/tests/Unit/AdmissionPolicyEnvironmentTest.php b/tests/Unit/AdmissionPolicyEnvironmentTest.php
new file mode 100644
index 000000000..b04244160
--- /dev/null
+++ b/tests/Unit/AdmissionPolicyEnvironmentTest.php
@@ -0,0 +1,157 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Unit;
+
+use Illuminate\Container\Container;
+use Illuminate\Foundation\Application;
+use InvalidArgumentException;
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\TestCase;
+
+class AdmissionPolicyEnvironmentTest extends TestCase
+{
+    /** @return iterable<string, array{string, string}> */
+    public static function policyVariables(): iterable
+    {
+        yield 'queue admission' => ['DW_TASK_QUEUE_ADMISSION_OVERRIDES', 'admission.queue_overrides'];
+        yield 'namespace admission' => ['DW_NAMESPACE_ADMISSION_OVERRIDES', 'namespace_admission.overrides'];
+        yield 'durable limits' => ['DW_NAMESPACE_DURABLE_LIMITS', 'namespace_durable_state.limits'];
+        yield 'durable hard limits' => ['DW_NAMESPACE_DURABLE_HARD_LIMITS', 'namespace_durable_state.hard_limits'];
+        yield 'durable overrides' => ['DW_NAMESPACE_DURABLE_OVERRIDES', 'namespace_durable_state.overrides'];
+        yield 'payload overrides' => ['DW_EXTERNAL_PAYLOAD_NAMESPACE_OVERRIDES', 'external_payload_transport.namespace_overrides'];
+    }
+
+    /** @return iterable<string, array{string, string}> */
+    public static function invalidPolicyValues(): iterable
+    {
+        foreach (self::policyVariables() as $policy => [$name]) {
+            $invalid = [
+                'unfinished' => '{"private-policy":',
+                'null' => 'null',
+                'array' => '[]',
+                'string' => '"private-policy"',
+                'number' => '0',
+                'boolean' => 'false',
+                'blank' => '',
+            ];
+            foreach ($invalid as $kind => $value) {
+                yield $policy.' / '.$kind => [$name, $value];
+            }
+        }
+    }
+
+    #[DataProvider('invalidPolicyValues')]
+    public function test_invalid_primary_policy_refuses_without_printing_its_value(string $name, string $value): void
+    {
+        $this->withEnvironment([$name => $value], function () use ($name): void {
+            try {
+                require dirname(__DIR__, 2).'/config/server.php';
+                self::fail('Invalid policy configuration was silently accepted.');
+            } catch (InvalidArgumentException $exception) {
+                self::assertStringContainsString($name, $exception->getMessage());
+                self::assertStringNotContainsString('private-policy', $exception->getMessage());
+                self::assertNull($exception->getPrevious());
+            }
+        });
+    }
+
+    #[DataProvider('policyVariables')]
+    public function test_empty_objects_and_valid_primary_policies_keep_their_values(string $name, string $path): void
+    {
+        $legacy = str_replace('DW_', 'WORKFLOW_SERVER_', $name);
+        $this->withEnvironment([$name => '{}', $legacy => '{invalid'], function () use ($path): void {
+            $config = require dirname(__DIR__, 2).'/config/server.php';
+            self::assertSame([], $this->atPath($config, $path));
+        });
+        $this->withEnvironment([$name => '{"default":{"max_requests_per_minute":1}}'], function () use ($path): void {
+            $config = require dirname(__DIR__, 2).'/config/server.php';
+            self::assertSame(['default' => ['max_requests_per_minute' => 1]], $this->atPath($config, $path));
+        });
+    }
+
+    #[DataProvider('policyVariables')]
+    public function test_omitted_policy_and_valid_legacy_policy_keep_existing_resolution(string $name, string $path): void
+    {
+        $legacy = str_replace('DW_', 'WORKFLOW_SERVER_', $name);
+        $this->withEnvironment([$name => null, $legacy => null], function () use ($path): void {
+            $config = require dirname(__DIR__, 2).'/config/server.php';
+            self::assertSame([], $this->atPath($config, $path));
+        });
+        $this->withEnvironment([$name => null, $legacy => '{"payments":{"max_requests_per_minute":1}}'], function () use ($path): void {
+            $config = require dirname(__DIR__, 2).'/config/server.php';
+            self::assertSame(['payments' => ['max_requests_per_minute' => 1]], $this->atPath($config, $path));
+        });
+    }
+
+    #[DataProvider('policyVariables')]
+    public function test_invalid_primary_does_not_fall_back_to_legacy(string $name, string $path): void
+    {
+        $legacy = str_replace('DW_', 'WORKFLOW_SERVER_', $name);
+        $this->withEnvironment([$name => 'null', $legacy => '{}'], function () use ($name): void {
+            $this->expectException(InvalidArgumentException::class);
+            $this->expectExceptionMessage($name);
+            require dirname(__DIR__, 2).'/config/server.php';
+        });
+    }
+
+    #[DataProvider('policyVariables')]
+    public function test_invalid_legacy_policy_names_the_selected_legacy_variable(string $name, string $path): void
+    {
+        $legacy = str_replace('DW_', 'WORKFLOW_SERVER_', $name);
+        $this->withEnvironment([$name => null, $legacy => '{invalid'], function () use ($legacy): void {
+            $this->expectException(InvalidArgumentException::class);
+            $this->expectExceptionMessage($legacy);
+            require dirname(__DIR__, 2).'/config/server.php';
+        });
+    }
+
+    /** @param array<string, string|null> $values */
+    private function withEnvironment(array $values, callable $action): void
+    {
+        $application = Container::getInstance();
+        new Application(dirname(__DIR__, 2));
+        $previous = [];
+        foreach ($values as $name => $value) {
+            $previous[$name] = [getenv($name), $_ENV[$name] ?? null, $_SERVER[$name] ?? null];
+            if ($value === null) {
+                putenv($name);
+                unset($_ENV[$name], $_SERVER[$name]);
+            } else {
+                putenv($name.'='.$value);
+                $_ENV[$name] = $value;
+                $_SERVER[$name] = $value;
+            }
+        }
+
+        try {
+            $action();
+        } finally {
+            Container::setInstance($application);
+            foreach ($previous as $name => [$process, $environment, $server]) {
+                $process === false ? putenv($name) : putenv($name.'='.$process);
+                if ($environment === null) {
+                    unset($_ENV[$name]);
+                } else {
+                    $_ENV[$name] = $environment;
+                }
+                if ($server === null) {
+                    unset($_SERVER[$name]);
+                } else {
+                    $_SERVER[$name] = $server;
+                }
+            }
+        }
+    }
+
+    /** @param array<string, mixed> $config */
+    private function atPath(array $config, string $path): mixed
+    {
+        foreach (explode('.', $path) as $key) {
+            $config = $config[$key];
+        }
+
+        return $config;
+    }
+}