@@ -0,0 +1,25 @@
+---
+'@objectstack/spec': minor
+'@objectstack/runtime': minor
+'@objectstack/objectql': minor
+'@objectstack/cli': minor
+'@objectstack/lint': minor
+'@object-ui/i18n': patch
+'@object-ui/app-shell': patch
+---
+
+feat(spec): a hook declares its refusal catalogue, and its body refuses by code, answered in the caller's language
+
+Clause-②: yes (widening)
+Metadata-protocol: added
+
+A hook can now declare `refusals`: one entry per SCREAMING_SNAKE code, each with the `message` the user reads and an optional 4xx `status` (default `400`). A sandboxed `body` then refuses by code only: it throws an error carrying a declared `code`, and the body runner answers with the entry. The message is translated through `hooks.<hook>.refusals.<CODE>.message` in the caller's locale, the code reaches the caller's error envelope as `declaredCode` (beside the status's registered `code`), and the status is the entry's. The body's own error text and `status` are not what the caller reads.
+
+- **Spec.** `HookSchema.refusals` (`HookRefusalSchema`: `message`, `status?`). A new `hooks` group on the translation bundle, `hooks.<hook>.refusals.<CODE>.message`, and `hookRefusalMessageKey`. A message is plain text: a `{{ }}` hole is refused at save, so a later parameter slot stays additive. `HookContext.session.locale` declares the caller's locale.
+- **Undeclared codes are refused loudly.** A code the body throws literally (`{ code: 'X' }`, or `e.code = 'X'; throw e`) that the catalogue does not declare fails the save at `body.source`. Any other undeclared code, and a throw with no code, is a `500` fault at run time that names the hook and the code. A catalogue on a hook with no sandboxed `js` body (an in-process `handler`, an expression body) is refused at save, since nothing would answer it. All of this applies only to a hook that declares `refusals`; a hook without one is answered exactly as before.
+- **Runtime.** The body runner resolves the throw against the catalogue and picks the translation through the `i18n` service, negotiated against the locales it holds. An error a `ctx.api` call raised that the body lets leave unchanged, a crash, and the sandbox's own faults pass through untouched. ObjectQL copies the request's locale onto the hook session.
+- **CLI.** `os i18n extract` scaffolds one key per declared entry and `os i18n check` counts them, in a new `hook` coverage bucket.
+- **Lint.** A translation keyed to a hook the stack does not define, or to a code its `refusals` does not declare, is reported as `translation-target-unknown`.
+- **Console.** The translation preview shows a `hooks` category (en/zh labels), and the translation loader lists `hooks` among the spec groups.
+
+Nothing to do for existing hooks. To use it, declare `refusals` on a sandboxed hook and throw its codes.
@@ -406,7 +406,7 @@ Three rules the shape enforces, all of them closed since #4001:
 
 - **The top level is the declared group set and nothing else** — `objects`,
   `picklists`, `apps`, `messages`, `globalActions`, `dashboards`, `datasets`,
-  `reports`, `pages`, `flows`, `positions`, `permissions`, `books`,
+  `reports`, `pages`, `flows`, `hooks`, `positions`, `permissions`, `books`,
   `metadataForms`, `settingsCommon`. A group invented beside them
   (`"account"`, `"fields"`, `"list"`, `"industries"`) is rejected **by name**
   at both authoring doors, with the group to use instead named in the
@@ -496,7 +496,7 @@ what the overlay writes back as the node's `title`.
 The contract is `t(key, locale, params?)` — the target locale is always passed
 explicitly, and the key itself is returned when no translation is found (there
 is no `defaultValue` option). The key is a **dot path into `TranslationData`**,
-so it starts at one of the fifteen declared groups.
+so it starts at one of the sixteen declared groups.
 
 ```typescript
 const i18n = kernel.getService('i18n');
@@ -1077,6 +1077,8 @@ beneath an action entry are judged the same way under either.
 | `positions.{name}` | a position's `name`, declared, or an audience anchor (`everyone`, `guest`) |
 | `permissions.{name}` | a permission set's `name`, declared |
 | `reports.{name}` | a report's `name`, declared |
+| `hooks.{hook}` | a hook's `name`, declared |
+| `hooks.{hook}.refusals.{code}` | a code that hook's `refusals` declares |
 | `flows.{flow}.screens.{node}` | the `id` of a `type: 'screen'` node in that flow, nodes nested in loop, parallel and try/catch regions included |
 | `flows.{flow}.screens.{node}.fields.{field}` | a `config.fields[].name` on that screen — an object-form screen (`config.objectName`) declares none, and its input labels live under `objects.{objectName}.fields` |
 
 
@@ -1782,6 +1782,7 @@ The published metadata item body, opaque by ruling (1C). Shape is the item's own
 | **reports** | `Record<string, { label?: string; description?: string; blocks?: Record<string, object> }>` | optional | Report translations keyed by report name |
 | **pages** | `Record<string, { label?: string; description?: string; title?: string; subtitle?: string; … }>` | optional | Page translations keyed by page name |
 | **flows** | `Record<string, { label?: string; successMessage?: string; errorMessage?: string; screens?: Record<string, object>; … }>` | optional | Screen-flow translations keyed by flow name |
+| **hooks** | `Record<string, { refusals?: Record<string, object> }>` | optional | Hook translations keyed by hook name |
 | **positions** | `Record<string, { label?: string; description?: string }>` | optional | Position translations keyed by position name |
 | **permissions** | `Record<string, { label?: string; description?: string }>` | optional | Permission-set translations keyed by permission-set name |
 | **books** | `Record<string, { label?: string; description?: string; groups?: Record<string, object> }>` | optional | Doc-book translations keyed by book name |
 
@@ -1,7 +1,7 @@
 ---
 title: Hook schema — Data Protocol property reference
 navTitle: Hook
-description: "Hook schemas of the ObjectStack Data Protocol: Hook, HookContext, HookEvent — each property with its type, default and a TypeScript example."
+description: "Hook schemas of the ObjectStack Data Protocol: Hook, HookContext, HookEvent, HookRefusal — each property with its type, default and a TypeScript example."
 ---
 
 {/* ⚠️  AUTO-GENERATED — DO NOT EDIT. Run build-docs.ts to regenerate. Hand-written docs live in the module folders under content/docs/. */}
@@ -13,8 +13,8 @@ description: "Hook schemas of the ObjectStack Data Protocol: Hook, HookContext,
 ## TypeScript Usage
 
 ```typescript
-import { HookSchema, HookContextSchema, HookEvent } from '@objectstack/spec/data';
-import type { Hook, HookContext } from '@objectstack/spec/data';
+import { HookSchema, HookContextSchema, HookEvent, HookRefusalSchema } from '@objectstack/spec/data';
+import type { Hook, HookContext, HookRefusal } from '@objectstack/spec/data';
 
 // Validate data
 const result = HookSchema.parse(data);
@@ -42,6 +42,7 @@ const result = HookSchema.parse(data);
 | **timeoutMs** | `number` | optional | Maximum execution time in milliseconds before the hook is aborted |
 | **timeout** | `never` | optional | [REMOVED] `hook.timeout` was removed in @objectstack/spec 17 — its unit (milliseconds) lived only in the description, beside a body-level `timeoutMs` and a `retryPolicy.backoffMs` that spell theirs, so the same number read as two conventions on one surface. Rename the key to `timeoutMs`; the value (milliseconds) is unchanged. Run `os migrate meta --from 17` to list the mechanical edits for existing sources; `--write` applies the ones it can prove, and you apply the rest by hand. |
 | **onError** | `Enum<'abort' \| 'log'>` | optional (default: `"abort"`) | Error handling strategy. abort: refuse the operation; a blocking hook's abort rolls the write back inside a unit of work, which the write door opens for an after* hook on an object on the default datasource whose driver declares transactions (elsewhere the caller is refused and the row stays stored). log: log the error and continue |
+| **refusals** | `Record<string, { message: string; status?: integer }>` | optional | Refusal catalogue keyed by the SCREAMING_SNAKE code the body throws: `{ message, status? }`. The body refuses by code only; the runtime answers with the declared message (translated through hooks.`<hook>`.refusals.`<CODE>`.message in the caller's locale) and status. A code not declared here is refused loudly — at save when the body throws it literally, otherwise at run time |
 | **runAs** | `Enum<'system' \| 'user' \| 'inherit'>` | optional (default: `"inherit"`) | Execution identity for the hook's ctx.api data operations: system = elevated (bypasses RLS), user = the triggering user (RLS-respecting), inherit = the context of the write that fired the hook (the pre-runAs behaviour; the default). A hook with no trigger user has no identity to scope to, so under user its ctx.api data operations are REFUSED — declare system to make the elevation explicit. This covers any hook fired by a write that carried no user (an isSystem plugin/service write; a system-elevated flow node). Elevation does not reach identity assignment: a system hook's governed writes (insert, update, delete, transfer, restore, purge) to sys_user_position, sys_user_permission_set, sys_invitation and sys_member are refused with PERMISSION_DENIED, and a system hook whose body names such a write is refused at save; declare user for position holdings and permission-set grants (the ADR-0090 D12 delegated-administration gate then judges the user the hook acts for), and change invitations and memberships through the organization endpoints. Scope: ctx.api only — condition evaluation, the readonly strip on ctx.input, ctx.session and async are unchanged. |
 | **_lock** | `Enum<'none' \| 'no-overlay' \| 'no-delete' \| 'full'>` | optional | Item-level lock — controls overlay & delete (ADR-0010). |
 | **_lockReason** | `string` | optional | Human-readable reason shown when a write is refused by _lock. |
@@ -79,6 +80,13 @@ L2 sandboxed JS body — runs inside an isolated VM with declared capabilities
 | **maxRetries** | `number` | optional (default: `3`) | Maximum retry attempts on failure |
 | **backoffMs** | `number` | optional (default: `1000`) | Backoff delay between retries in milliseconds |
 
+### Nested Shape: `Hook.refusals[string]`
+
+| Property | Type | Required | Description |
+| :--- | :--- | :--- | :--- |
+| **message** | `string` | ✅ | The sentence the user reads when the body throws this code — plain text in the source locale, translated whole through hooks.`<hook>`.refusals.`<CODE>`.message in the caller's locale; a `{{ }}` hole is refused |
+| **status** | `integer` | optional | HTTP status the refusal is answered with (4xx; a refusal is never a fault). Absent: 400. A status the body itself sets on the throw is not read — the catalogue decides |
+
 
 ---
 
@@ -126,6 +134,7 @@ L2 sandboxed JS body — runs inside an isolated VM with declared capabilities
 | **skipAutomations** | `boolean` | optional | True when metadata-bound automation hooks must be suppressed for this write — e.g. a data import the system principal runs with "run automations" unchecked, or the system principal's import undo. Implies skipTriggers; code-registered system hooks (audit, security) still run. Only the system principal may take an app's declared controls off a write, and the import undo door is not an exception: an undo by any other caller runs under the object's hooks, record-change triggers and state machine. |
 | **positions** | `string[]` | optional | Position names held by the caller (ADR-0090 D3; formerly `roles`), copied from ExecutionContext.positions. For hook READS only — e.g. tailoring a message, or branching a business rule the hook runs through its own `ctx.api` channel. Authorization is decided by the security service on the ExecutionContext (permissions / positions / derived posture); this is NOT an authorization input and a hook must not gate a write by testing it. A hook context carries no `services` key, so the sharing service cannot be called from one either — the sharing gates already ran inside the engine before the hook chain. |
 | **preserveAudit** | `boolean` | optional | True when this write is a historical import that must KEEP its caller-supplied updated_at/updated_by (and the readonly audit family) instead of being stamped with the import instant. Server-set, opt-in, absent on normal writes; read by the built-in audit hook. A stamping policy, not an authorization input. |
+| **locale** | `string` | optional | The caller's locale (BCP-47), copied from ExecutionContext.locale: the request's Accept-Language, else the localization setting; absent on a write no person asked for. The body runner answers a declared refusal (HookSchema.refusals) in it. Descriptive only — not an authorization input. |
 | **roles** | `never` | optional | [REMOVED] `HookContext.session.roles` was removed in @objectstack/spec 17.0.0 (ADR-0049 D2) — it was declared, read by two dead exemption branches, and never produced: ObjectQL's `buildSession()` builds the session field by field and has never written `roles`, so every read resolved `undefined` and a guard keyed on it was dead code that merely LOOKED like an authorization decision. Delete the key. To gate a hook on the caller, read `ctx.session.userId` / `ctx.session.isSystem`; to judge PRIVILEGE, ask the security service, which evaluates the ADR-0095 vocabulary on the execution context — capability grants (`permissions`), placements (`positions`) and the derived posture — never a role-name string comparison (ADR-0090 D3 bans the `role` spelling outright). Nothing to migrate: a HookContext is built per operation by the engine and never stored, so no metadata source carries this key. NOTE an ACTION body's `ctx.session` is a different object and still carries its own `roles` array today; that surface is tracked separately and is not what this key was. |
 
 ### Nested Shape: `HookContext.provenance`
@@ -164,3 +173,15 @@ L2 sandboxed JS body — runs inside an isolated VM with declared capabilities
 
 ---
 
+## HookRefusal
+
+### Properties
+
+| Property | Type | Required | Description |
+| :--- | :--- | :--- | :--- |
+| **message** | `string` | ✅ | The sentence the user reads when the body throws this code — plain text in the source locale, translated whole through hooks.`<hook>`.refusals.`<CODE>`.message in the caller's locale; a `{{ }}` hole is refused |
+| **status** | `integer` | optional | HTTP status the refusal is answered with (4xx; a refusal is never a fault). Absent: 400. A status the body itself sets on the throw is not read — the catalogue decides |
+
+
+---
+
@@ -1,7 +1,7 @@
 ---
 title: Protocol reference — every schema by module
 navTitle: Protocol Reference
-description: Every schema published by @objectstack/spec — 1556 schemas across 14 protocol modules
+description: Every schema published by @objectstack/spec — 1557 schemas across 14 protocol modules
 ---
 
 {/* ⚠️  AUTO-GENERATED — DO NOT EDIT. Run build-docs.ts to regenerate. Hand-written docs live in the module folders under content/docs/. */}
@@ -23,7 +23,7 @@ counts are sums of the rows they head. Regenerate with
 | [AI Protocol](/docs/references/ai) | 12 | 68 | Agents, tools, skills, RAG and knowledge sources, model registry, conversations. |
 | [API Protocol](/docs/references/api) | 32 | 438 | REST contracts, endpoints, routing, realtime, batch, discovery. |
 | [Automation Protocol](/docs/references/automation) | 15 | 77 | Flows and their nodes, approvals, ETL pipelines, webhooks, state machines, execution records. |
-| [Data Protocol](/docs/references/data) | 31 | 184 | Objects, fields, queries, filters, datasources and drivers — the ObjectQL layer. |
+| [Data Protocol](/docs/references/data) | 31 | 185 | Objects, fields, queries, filters, datasources and drivers — the ObjectQL layer. |
 | [Identity Protocol](/docs/references/identity) | 5 | 27 | Users and accounts, organizations, positions, SCIM provisioning. |
 | [Integration Protocol](/docs/references/integration) | 1 | 12 | The single connector protocol (ADR-0097) — catalog descriptors and provider-bound instances. |
 | [Kernel Protocol](/docs/references/kernel) | 29 | 151 | Plugin lifecycle and manifests, capabilities and security, metadata loading, service registry. |
@@ -34,7 +34,7 @@ counts are sums of the rows they head. Regenerate with
 | [Studio Protocol](/docs/references/studio) | 3 | 35 | Studio designer metadata — the authoring surfaces for the protocols above. |
 | [System Protocol](/docs/references/system) | 37 | 287 | The runtime environment — logging, jobs, cache, metrics, notifications, i18n and compliance. |
 | [UI Protocol](/docs/references/ui) | 16 | 171 | Apps, pages, views, dashboards, reports, actions and themes — the ObjectUI layer. |
-| **Total** | **202** | **1556** | 14 protocol modules |
+| **Total** | **202** | **1557** | 14 protocol modules |
 
 ---
 
@@ -132,7 +132,7 @@ Flows and their nodes, approvals, ETL pipelines, webhooks, state machines, execu
 
 ## Data Protocol
 
-**Source:** `packages/spec/src/data/` · **Import:** `@objectstack/spec/data` · **31 pages, 184 schemas**
+**Source:** `packages/spec/src/data/` · **Import:** `@objectstack/spec/data` · **31 pages, 185 schemas**
 
 Objects, fields, queries, filters, datasources and drivers — the ObjectQL layer.
 
@@ -159,7 +159,7 @@ Objects, fields, queries, filters, datasources and drivers — the ObjectQL laye
 | [`field.zod.ts`](/docs/references/data/field) | `CurrencyConfig`, `CurrencyValue`, `Field`, `FieldMaskingKeep`, `FieldMaskingRule`, `FieldType`, `InlineGridColumn`, `LocationCoordinates`, `SelectOption`, `UniqueScope` |
 | [`field-value.zod.ts`](/docs/references/data/field-value) | `Address`, `AddressValue`, `CalendarDateValue`, `ClockTimeValue`, `FileLikeValue`, `FileReferenceIdValue`, `FileRefusedValue`, `FileValue`, `InstantValue`, `LocationValue`, `ReferenceIdValue` |
 | [`filter.zod.ts`](/docs/references/data/filter) | `ComparisonOperator`, `EqualityOperator`, `FieldOperators`, `FieldReference`, `FilterArray`, `FilterCondition`, `NormalizedFilter`, `NowAnchor`, `QueryFilter`, `RangeOperator`, `SetOperator`, `SpecialOperator`, `StringOperator` |
-| [`hook.zod.ts`](/docs/references/data/hook) | `Hook`, `HookContext`, `HookEvent` |
+| [`hook.zod.ts`](/docs/references/data/hook) | `Hook`, `HookContext`, `HookEvent`, `HookRefusal` |
 | [`hook-body.zod.ts`](/docs/references/data/hook-body) | `ExpressionBody`, `HookBody`, `HookBodyCapability`, `ScriptBody` |
 | [`mapping.zod.ts`](/docs/references/data/mapping) | `ImportFieldMapping`, `Mapping`, `TransformType` |
 | [`object.zod.ts`](/docs/references/data/object) | `ApiMethod`, `ApiOperation`, `Index`, `Lifecycle`, `LifecycleClass`, `Object`, `ObjectAccessConfig`, `ObjectCapabilities`, `ObjectExtension`, `ObjectExternalBinding`, `ObjectFieldGroup`, `ObjectOwnershipEnum`, `ObjectRequiredPermissions`, `PerOperationRequiredPermissions`, `RowCrudActionOverride`, `TenancyConfig` |