diff --git a/apps/supervisor/src/env.ts b/apps/supervisor/src/env.ts
index cd9bf5bead..2921e5e35b 100644
--- a/apps/supervisor/src/env.ts
+++ b/apps/supervisor/src/env.ts
@@ -1,7 +1,7 @@
 import { randomUUID } from "crypto";
 import { env as stdEnv } from "std-env";
 import { z } from "zod";
-import { AdditionalEnvVars, BoolEnv } from "./envUtil.js";
+import { AdditionalEnvVars, BoolEnv, CoercedBoolean } from "./envUtil.js";
 
 const Env = z.object({
   // This will come from `spec.nodeName` in k8s
@@ -45,7 +45,7 @@ const Env = z.object({
   // Used by the workload manager, e.g docker/k8s
   DOCKER_NETWORK: z.string().default("host"),
   OTEL_EXPORTER_OTLP_ENDPOINT: z.string().url(),
-  ENFORCE_MACHINE_PRESETS: z.coerce.boolean().default(false),
+  ENFORCE_MACHINE_PRESETS: CoercedBoolean.default(false),
   KUBERNETES_IMAGE_PULL_SECRETS: z.string().optional(), // csv
 
   // Used by the resource monitor
diff --git a/apps/supervisor/src/envUtil.ts b/apps/supervisor/src/envUtil.ts
index 41dd5ca22a..623af865b6 100644
--- a/apps/supervisor/src/envUtil.ts
+++ b/apps/supervisor/src/envUtil.ts
@@ -37,3 +37,12 @@ export const AdditionalEnvVars = z.preprocess((val) => {
     return undefined;
   }
 }, z.record(z.string(), z.string()).optional());
+
+/**
+ * Zod's `z.coerce.boolean()` doesn't work as _expected_ with "true" and "false" strings.
+ * as it coerces both to `true`. This type is a workaround for that.
+ */
+export const CoercedBoolean = z.union([
+  z.boolean(),
+  z.enum(["true", "false"]).transform((v) => v === "true"),
+]);
diff --git a/apps/webapp/app/components/runs/v3/RunFilters.tsx b/apps/webapp/app/components/runs/v3/RunFilters.tsx
index 393acb7616..8c6fa9c0b4 100644
--- a/apps/webapp/app/components/runs/v3/RunFilters.tsx
+++ b/apps/webapp/app/components/runs/v3/RunFilters.tsx
@@ -53,6 +53,7 @@ import {
   TaskRunStatusCombo,
 } from "./TaskRunStatus";
 import { TaskTriggerSourceIcon } from "./TaskTriggerSource";
+import { CoercedBoolean } from "~/utils/zod";
 
 export const TaskAttemptStatus = z.enum(allTaskRunStatuses);
 
@@ -83,7 +84,7 @@ export const TaskRunListSearchFilters = z.object({
   period: z.preprocess((value) => (value === "all" ? undefined : value), z.string().optional()),
   from: z.coerce.number().optional(),
   to: z.coerce.number().optional(),
-  rootOnly: z.coerce.boolean().optional(),
+  rootOnly: CoercedBoolean.optional(),
   batchId: z.string().optional(),
   runId: z.string().optional(),
   scheduleId: z.string().optional(),
diff --git a/apps/webapp/app/env.server.ts b/apps/webapp/app/env.server.ts
index beceac9a5f..b869274501 100644
--- a/apps/webapp/app/env.server.ts
+++ b/apps/webapp/app/env.server.ts
@@ -2,6 +2,7 @@ import { z } from "zod";
 import { SecretStoreOptionsSchema } from "./services/secrets/secretStoreOptionsSchema.server";
 import { isValidDatabaseUrl } from "./utils/db";
 import { isValidRegex } from "./utils/regex";
+import { CoercedBoolean } from "./utils/zod";
 
 const EnvironmentSchema = z.object({
   NODE_ENV: z.union([z.literal("development"), z.literal("production"), z.literal("test")]),
@@ -50,7 +51,7 @@ const EnvironmentSchema = z.object({
   RESEND_API_KEY: z.string().optional(),
   SMTP_HOST: z.string().optional(),
   SMTP_PORT: z.coerce.number().optional(),
-  SMTP_SECURE: z.coerce.boolean().optional(),
+  SMTP_SECURE: CoercedBoolean.optional(),
   SMTP_USER: z.string().optional(),
   SMTP_PASSWORD: z.string().optional(),
 
@@ -338,7 +339,7 @@ const EnvironmentSchema = z.object({
   ALERT_RESEND_API_KEY: z.string().optional(),
   ALERT_SMTP_HOST: z.string().optional(),
   ALERT_SMTP_PORT: z.coerce.number().optional(),
-  ALERT_SMTP_SECURE: z.coerce.boolean().optional(),
+  ALERT_SMTP_SECURE: CoercedBoolean.optional(),
   ALERT_SMTP_USER: z.string().optional(),
   ALERT_SMTP_PASSWORD: z.string().optional(),
   ALERT_RATE_LIMITER_EMISSION_INTERVAL: z.coerce.number().int().default(2_500),
@@ -378,7 +379,7 @@ const EnvironmentSchema = z.object({
   MAX_SEQUENTIAL_INDEX_FAILURE_COUNT: z.coerce.number().default(96),
 
   LOOPS_API_KEY: z.string().optional(),
-  MARQS_DISABLE_REBALANCING: z.coerce.boolean().default(false),
+  MARQS_DISABLE_REBALANCING: CoercedBoolean.default(false),
   MARQS_VISIBILITY_TIMEOUT_MS: z.coerce
     .number()
     .int()
@@ -452,7 +453,7 @@ const EnvironmentSchema = z.object({
   RUN_ENGINE_TIMEOUT_PENDING_CANCEL: z.coerce.number().int().default(60_000),
   RUN_ENGINE_TIMEOUT_EXECUTING: z.coerce.number().int().default(60_000),
   RUN_ENGINE_TIMEOUT_EXECUTING_WITH_WAITPOINTS: z.coerce.number().int().default(60_000),
-  RUN_ENGINE_DEBUG_WORKER_NOTIFICATIONS: z.coerce.boolean().default(false),
+  RUN_ENGINE_DEBUG_WORKER_NOTIFICATIONS: CoercedBoolean.default(false),
   RUN_ENGINE_PARENT_QUEUE_LIMIT: z.coerce.number().int().default(1000),
   RUN_ENGINE_CONCURRENCY_LIMIT_BIAS: z.coerce.number().default(0.75),
   RUN_ENGINE_AVAILABLE_CAPACITY_BIAS: z.coerce.number().default(0.3),
diff --git a/apps/webapp/app/utils/zod.ts b/apps/webapp/app/utils/zod.ts
index 950b2ddc25..c932b9d6d6 100644
--- a/apps/webapp/app/utils/zod.ts
+++ b/apps/webapp/app/utils/zod.ts
@@ -20,3 +20,12 @@ export const CoercedDate = z.preprocess((arg) => {
 
   return arg;
 }, z.date().optional());
+
+/**
+ * Zod's `z.coerce.boolean()` doesn't work as _expected_ with "true" and "false" strings.
+ * as it coerces both to `true`. This type is a workaround for that.
+ */
+export const CoercedBoolean = z.union([
+  z.boolean(),
+  z.enum(["true", "false"]).transform((v) => v === "true"),
+]);