diff --git a/backend/tests/test_role_matrix.py b/backend/tests/test_role_matrix.py
index 622a63a..8ec7eb3 100644
--- a/backend/tests/test_role_matrix.py
+++ b/backend/tests/test_role_matrix.py
@@ -2,8 +2,7 @@
 
 Catches regressions where a writer-required endpoint silently accepts
 viewer or outsider credentials. Admin is excluded on purpose: admins
-bypass every check, so admin coverage hides role bugs (see TG2 in
-PRE-RELEASE_V1.0.md).
+bypass every check, so admin coverage hides role bugs.
 """
 import pytest
 
diff --git a/frontend/src/__tests__/CustomFieldInput.test.jsx b/frontend/src/__tests__/CustomFieldInput.test.jsx
index 0685185..00b3cf9 100644
--- a/frontend/src/__tests__/CustomFieldInput.test.jsx
+++ b/frontend/src/__tests__/CustomFieldInput.test.jsx
@@ -1,6 +1,6 @@
 import { useState } from "react"
 import { describe, it, expect, vi } from "vitest"
-import { render, screen } from "@testing-library/react"
+import { fireEvent, render, screen } from "@testing-library/react"
 import userEvent from "@testing-library/user-event"
 
 import "../i18n"
@@ -50,16 +50,39 @@ describe("CustomFieldsForm", () => {
     expect(onChange).toHaveBeenLastCalledWith({ priority: "P0" })
   })
 
-  it("toggles boolean fields via checkbox", async () => {
+  it("emits true when the user picks Yes from the tri-state bool select", async () => {
     const onChange = vi.fn()
     const definitions = [buildDefinition({ key: "is_blocker", label: "Blocker", type: "bool" })]
 
     render(<CustomFieldsForm definitions={definitions} values={{}} onChange={onChange} />)
-    await userEvent.click(screen.getByRole("checkbox"))
+    fireEvent.click(screen.getByRole("combobox"))
+    fireEvent.click(screen.getByRole("option", { name: "Yes" }))
 
     expect(onChange).toHaveBeenLastCalledWith({ is_blocker: true })
   })
 
+  it("emits false explicitly when the user picks No (distinguishing it from unset)", async () => {
+    const onChange = vi.fn()
+    const definitions = [buildDefinition({ key: "is_blocker", label: "Blocker", type: "bool" })]
+
+    render(<CustomFieldsForm definitions={definitions} values={{}} onChange={onChange} />)
+    fireEvent.click(screen.getByRole("combobox"))
+    fireEvent.click(screen.getByRole("option", { name: "No" }))
+
+    expect(onChange).toHaveBeenLastCalledWith({ is_blocker: false })
+  })
+
+  it("surfaces the declared default value inside the unset option label", async () => {
+    const definitions = [buildDefinition({
+      key: "is_blocker", label: "Blocker", type: "bool", default_value: false,
+    })]
+
+    render(<CustomFieldsForm definitions={definitions} values={{}} onChange={vi.fn()} />)
+    fireEvent.click(screen.getByRole("combobox"))
+
+    expect(screen.getByRole("option", { name: /Default \(No\)/i })).toBeInTheDocument()
+  })
+
   it("removes the key when the value becomes empty", async () => {
     const onChange = vi.fn()
     const definitions = [buildDefinition()]
diff --git a/frontend/src/__tests__/customFieldDefaults.test.js b/frontend/src/__tests__/customFieldDefaults.test.js
new file mode 100644
index 0000000..b1758ac
--- /dev/null
+++ b/frontend/src/__tests__/customFieldDefaults.test.js
@@ -0,0 +1,48 @@
+import { describe, it, expect } from "vitest"
+import { coerceDefault } from "../lib/customFieldDefaults"
+
+describe("coerceDefault bool", () => {
+  it.each(["true", "True", "TRUE", "  true  ", "1", "yes", "y", "on", "sí", "Si", "S"])(
+    "treats %p as true", input => {
+      expect(coerceDefault("bool", input)).toBe(true)
+    },
+  )
+
+  it.each(["false", "False", "FALSE", "0", "no", "N", "off", "  no  "])(
+    "treats %p as false", input => {
+      expect(coerceDefault("bool", input)).toBe(false)
+    },
+  )
+
+  it("treats anything unrecognized as false", () => {
+    expect(coerceDefault("bool", "maybe")).toBe(false)
+    expect(coerceDefault("bool", "")).toBe(false)
+  })
+})
+
+describe("coerceDefault multi_select", () => {
+  it("splits on the pipe character so commas inside values survive", () => {
+    expect(coerceDefault("multi_select", "web, mobile|api|desktop"))
+      .toEqual(["web, mobile", "api", "desktop"])
+  })
+
+  it("trims whitespace and drops empty segments", () => {
+    expect(coerceDefault("multi_select", " p0 |  | p1 "))
+      .toEqual(["p0", "p1"])
+  })
+
+  it("returns a single-element array for a value without separators", () => {
+    expect(coerceDefault("multi_select", "p0")).toEqual(["p0"])
+  })
+})
+
+describe("coerceDefault other types", () => {
+  it("parses number defaults", () => {
+    expect(coerceDefault("number", "42")).toBe(42)
+  })
+
+  it("returns text defaults verbatim", () => {
+    expect(coerceDefault("text", "anything"))
+      .toBe("anything")
+  })
+})
diff --git a/frontend/src/components/customField/CustomFieldInput.jsx b/frontend/src/components/customField/CustomFieldInput.jsx
index d39327b..4a902f0 100644
--- a/frontend/src/components/customField/CustomFieldInput.jsx
+++ b/frontend/src/components/customField/CustomFieldInput.jsx
@@ -73,14 +73,8 @@ function FieldControl({ definition, value, onChange }) {
         />
       )
     case "bool":
-      return (
-        <input
-          type="checkbox"
-          checked={!!value}
-          onChange={event => onChange(event.target.checked)}
-          className="h-4 w-4"
-        />
-      )
+      return <BoolControl definition={definition} value={value} onChange={onChange} />
+
     case "date":
       return (
         <Input
@@ -98,6 +92,34 @@ function FieldControl({ definition, value, onChange }) {
   }
 }
 
+const BOOL_TRUE = "__true__"
+const BOOL_FALSE = "__false__"
+
+function BoolControl({ definition, value, onChange }) {
+  const { t } = useTranslation("customFields")
+  const selected = value === true ? BOOL_TRUE : value === false ? BOOL_FALSE : NONE_VALUE
+  const hasDefault = definition.default_value === true || definition.default_value === false
+  const unsetLabel = hasDefault
+    ? t("bool.unsetWithDefault", { value: definition.default_value ? t("bool.yes") : t("bool.no") })
+    : t("bool.unset")
+  const pickValue = next => {
+    if (next === BOOL_TRUE) onChange(true)
+    else if (next === BOOL_FALSE) onChange(false)
+    else onChange(undefined)
+  }
+  return (
+    <Select value={selected} onValueChange={pickValue}>
+      <SelectTrigger><SelectValue /></SelectTrigger>
+      <SelectContent>
+        <SelectItem value={NONE_VALUE}>{unsetLabel}</SelectItem>
+        <SelectItem value={BOOL_TRUE}>{t("bool.yes")}</SelectItem>
+        <SelectItem value={BOOL_FALSE}>{t("bool.no")}</SelectItem>
+      </SelectContent>
+    </Select>
+  )
+}
+
+
 function SingleSelectControl({ definition, value, onChange }) {
   const { t } = useTranslation("customFields")
   const selected = value ?? NONE_VALUE
diff --git a/frontend/src/components/customField/CustomFieldsPanel.jsx b/frontend/src/components/customField/CustomFieldsPanel.jsx
index 33495c4..57675ec 100644
--- a/frontend/src/components/customField/CustomFieldsPanel.jsx
+++ b/frontend/src/components/customField/CustomFieldsPanel.jsx
@@ -14,6 +14,7 @@ import {
   useReorderCustomFields,
   useUnarchiveCustomField,
 } from "../../hooks/useCustomFields"
+import { coerceDefault } from "../../lib/customFieldDefaults"
 import { Button } from "../ui/button"
 import { Dialog, DialogContent, DialogHeader, DialogTitle } from "../ui/dialog"
 import { EmptyState } from "../ui/empty-state"
@@ -332,9 +333,15 @@ function CreateFieldDialog({ open, onOpenChange, projectId, defaultEntityType, o
             <Input
               value={defaultValue}
               onChange={event => setDefaultValue(event.target.value)}
-              placeholder={isSelect ? "value" : ""}
+              placeholder={defaultValuePlaceholder(type)}
             />
-            <p className="text-xs text-gray-500 dark:text-gray-400">{t("fields.defaultHint")}</p>
+            <p className="text-xs text-gray-500 dark:text-gray-400">
+              {type === "multi_select"
+                ? t("fields.defaultHintMultiSelect")
+                : type === "bool"
+                  ? t("fields.defaultHintBool")
+                  : t("fields.defaultHint")}
+            </p>
           </div>
           <label className="flex items-center gap-2 text-sm">
             <input
@@ -358,6 +365,14 @@ function CreateFieldDialog({ open, onOpenChange, projectId, defaultEntityType, o
   )
 }
 
+function defaultValuePlaceholder(type) {
+  if (type === "multi_select") return "p0|p1|p2"
+  if (type === "bool") return "true / false"
+  if (type === "single_select") return "value"
+  return ""
+}
+
+
 function parseOptions(text) {
   return text
     .split("\n")
@@ -369,9 +384,3 @@ function parseOptions(text) {
     })
 }
 
-function coerceDefault(type, raw) {
-  if (type === "number") return Number(raw)
-  if (type === "bool") return raw === "true" || raw === "1"
-  if (type === "multi_select") return raw.split(",").map(item => item.trim()).filter(Boolean)
-  return raw
-}
diff --git a/frontend/src/i18n/locales/en/customFields.json b/frontend/src/i18n/locales/en/customFields.json
index 9107b52..61a7e95 100644
--- a/frontend/src/i18n/locales/en/customFields.json
+++ b/frontend/src/i18n/locales/en/customFields.json
@@ -25,7 +25,9 @@
     "optionsHint": "One per line — value | label",
     "required": "Required on create",
     "default": "Default value",
-    "defaultHint": "Pre-fills new records. Required for executions with required=true."
+    "defaultHint": "Pre-fills new records. Required for executions with required=true.",
+    "defaultHintBool": "Pre-fills new records. Accepts true/false/yes/no/1/0 (case-insensitive).",
+    "defaultHintMultiSelect": "Pre-fills new records. Use | to separate values when they contain commas."
   },
   "actions": {
     "save": "Save",
@@ -70,5 +72,11 @@
   "columns": {
     "title": "Columns",
     "subtitle": "Show custom fields"
+  },
+  "bool": {
+    "yes": "Yes",
+    "no": "No",
+    "unset": "Not set",
+    "unsetWithDefault": "Default ({{value}})"
   }
 }
diff --git a/frontend/src/i18n/locales/es/customFields.json b/frontend/src/i18n/locales/es/customFields.json
index af8a529..76f314e 100644
--- a/frontend/src/i18n/locales/es/customFields.json
+++ b/frontend/src/i18n/locales/es/customFields.json
@@ -25,7 +25,9 @@
     "optionsHint": "Una por línea — valor | etiqueta",
     "required": "Obligatorio al crear",
     "default": "Valor por defecto",
-    "defaultHint": "Pre-rellena los nuevos registros. Obligatorio para ejecuciones con required=true."
+    "defaultHint": "Pre-rellena los nuevos registros. Obligatorio para ejecuciones con required=true.",
+    "defaultHintBool": "Pre-rellena los nuevos registros. Acepta true/false/sí/no/1/0 (sin distinguir mayúsculas).",
+    "defaultHintMultiSelect": "Pre-rellena los nuevos registros. Usa | para separar valores cuando contienen comas."
   },
   "actions": {
     "save": "Guardar",
@@ -70,5 +72,11 @@
   "columns": {
     "title": "Columnas",
     "subtitle": "Mostrar campos personalizados"
+  },
+  "bool": {
+    "yes": "Sí",
+    "no": "No",
+    "unset": "Sin establecer",
+    "unsetWithDefault": "Por defecto ({{value}})"
   }
 }
diff --git a/frontend/src/lib/customFieldDefaults.js b/frontend/src/lib/customFieldDefaults.js
new file mode 100644
index 0000000..6bc0395
--- /dev/null
+++ b/frontend/src/lib/customFieldDefaults.js
@@ -0,0 +1,28 @@
+// Coerce admin-typed "default value" strings from the custom-field
+// dialog into the typed payload the API expects. Lives apart from
+// `CustomFieldsPanel.jsx` so the rules are unit-testable and a single
+// fix covers every entry point.
+
+const TRUE_STRINGS = new Set(["true", "1", "yes", "y", "on", "sí", "si", "s"])
+const FALSE_STRINGS = new Set(["false", "0", "no", "n", "off"])
+const MULTI_SELECT_SEPARATOR = "|"
+
+
+export function coerceDefault(type, raw) {
+  if (type === "number") return Number(raw)
+  if (type === "bool") return coerceBool(raw)
+  if (type === "multi_select") {
+    return String(raw)
+      .split(MULTI_SELECT_SEPARATOR)
+      .map(item => item.trim())
+      .filter(Boolean)
+  }
+  return raw
+}
+
+
+function coerceBool(raw) {
+  const normalized = String(raw).toLowerCase().trim()
+  if (FALSE_STRINGS.has(normalized)) return false
+  return TRUE_STRINGS.has(normalized)
+}