feat(spec): assignment values may be a CEL value envelope — the expression ledger gains the value role (#15113)

* wip(spec): assignment value role — ledger entry, wildcard, envelope contract, pins, docs, changeset

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0174WZTU6XcFcS7g2kykC53i

* wip(spec): eager value schema so the xExpression marker reaches JSON Schema; array-form prescription on the record type error

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0174WZTU6XcFcS7g2kykC53i

* feat(spec): assignment value may be a CEL value envelope — the expression ledger gains the value role

FLOW_NODE_EXPRESSION_PATHS gains the assignment entry at assignments.* with the
new value role; ledger paths accept a * segment (every key of an object, the
sibling of []); resolveFlowNodeExpressions emits only envelope-shaped objects
for a value slot, so a plain string stays {token} interpolation and every
pre-existing entry resolves byte-identically. AssignmentConfigSchema /
AssignmentValueSchema / AssignmentExpressionValueSchema declare the assignment
node's value contract (ExpressionSchema, safeExtended to the cel dialect,
beside interpolation and literals); a malformed envelope is refused at the
variable's path with a fixed leading sentence; the map value carries
xExpression: value as the ledger's declaration channel. Docs page, generated
artifacts, and a spec minor changeset. The executor half (evaluation,
validateExpression value checks, the reconciliation ratchet's marker table)
is service-automation's and is reported, not edited.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0174WZTU6XcFcS7g2kykC53i

* fix(spec): ADR-0122 Parsed aliases for the assignment value types; ADR-0090 reserved word in the flows page

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0174WZTU6XcFcS7g2kykC53i

* wip(spec,service-automation): A2 — assignment value slot reaches the ledger ratchet; ratchet learns the value marker and the additionalProperties walk

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0174WZTU6XcFcS7g2kykC53i

* chore(spec): regenerate api-surface and export-origins for the ledger-declared node config map

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0174WZTU6XcFcS7g2kykC53i

* chore(spec): regenerate the unknown-key strictness ledger from the merged tree

The os-regen merge driver deferred docs/audits/2026-07-unknown-key-strictness-ledger.counts.md (changed on both sides since the merge base); regenerated with pnpm --filter @objectstack/spec gen:strictness-ledger on the merged tree.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0174WZTU6XcFcS7g2kykC53i

---------

Co-authored-by: Claude <noreply@anthropic.com>

Author: claude[bot]

.changeset/assignment-value-role-cel-envelope.md

@@ -0,0 +1,42 @@
+---
+"@objectstack/spec": minor
+---
+
+feat(spec): an `assignment` value may be a CEL value envelope — the expression ledger gains the `value` role
+
+An assignment's whole job is to compute a value into a variable, yet CEL was
+reachable from flow metadata only where the answer had to be a boolean
+(`condition`, `decision.conditions[].expression`, a screen field's
+`visibleWhen`): `FLOW_NODE_EXPRESSION_PATHS` declared two roles, `predicate`
+and `flow-template`, and the `assignment` node's values were `{token}`
+interpolation only. So the stdlib the platform already declares, documents and
+tests — `joinNonEmpty` and the rest of `CEL_STDLIB_FUNCTIONS` — could not be
+called from metadata, and the commonest outbound shape a business application
+has (one digest message listing a recipient's N records) needed a `script`
+node.
+
+Ruled (maintainer, 2026-09-02): the rendering half only, no new vocabulary.
+
+- `FlowNodeExpressionRole` gains `'value'`: a slot whose authored value may be a
+  `{ dialect: 'cel', source }` expression envelope evaluated by the expression
+  engine to the value the variable takes — not a predicate, not a template.
+  The ledger gains the `assignment` entry at `assignments.*`; ledger paths now
+  accept a `*` segment ("every key of this object", the sibling of `[]`), and
+  `resolveFlowNodeExpressions` emits only envelope-shaped objects for a `value`
+  slot — a plain string there stays `{token}` interpolation. Every entry that
+  existed before resolves byte-identically. `isExpressionEnvelopeShaped` is
+  the exported recognizer both halves discriminate on.
+- `AssignmentConfigSchema` / `AssignmentValueSchema` /
+  `AssignmentExpressionValueSchema` declare the `assignment` node's value
+  contract: a string (`{token}` interpolation), a CEL value envelope (the
+  `ExpressionSchema` spelling, narrowed to the `cel` dialect), or any other
+  literal. Every value that parsed before still parses; the one newly refused
+  shape is a malformed envelope (no `source`, an empty or non-string `source`,
+  a `template` / `cron` / unknown dialect), refused at the variable's path with
+  a fixed leading sentence. The map value carries `.meta({ xExpression:
+  'value' })`, the declaration channel the ledger reads for this slot.
+
+The executor half is a separate change in `@objectstack/service-automation`:
+until it lands, the built-in `assignment` executor still writes an envelope
+object into the variable verbatim and `notify` renders it as JSON, and the
+ledger's reconciliation ratchet there does not yet know the `value` marker.

content/docs/automation/flows.mdx

@@ -176,6 +176,47 @@ or missing-`required` violation (#4277). A node type that publishes no
 }
 ```
 
+**Assignment (set variables):**
+
+```typescript
+{
+  id: 'build_digest',
+  type: 'assignment',
+  label: 'Build digest',
+  config: {
+    assignments: {
+      // `{token}` flow interpolation — a sole token keeps the token's type,
+      // text with holes stays text
+      owner_name: '{manager.name}',
+      // CEL value envelope — evaluated by the expression engine to a value, so
+      // the declared CEL stdlib is reachable from metadata: one line per task
+      digest: { dialect: 'cel', source: 'joinNonEmpty(overdue_tasks.map(t, t.subject), "\\n")' },
+    },
+  },
+}
+```
+
+A value's **shape** selects its form — there is no mode key. A plain string is
+always `{token}` interpolation (a bare `a + b` is the literal text `a + b`, not
+CEL); an object that names a `dialect` is an expression envelope and must be a
+valid `cel` one — a missing or empty `source`, or a `template` / `cron`
+dialect, is refused at the variable's path. Numbers, booleans, arrays and plain
+objects are assigned as literals. A later `notify` node renders the variable as
+any other: `message: '{digest}'`.
+
+<Callout type="warn" title="The contract landed first; the executor half follows">
+
+The envelope form is what `@objectstack/spec` declares — the expression
+ledger's `value` entry and `AssignmentConfigSchema`, the half ruled in
+[#14149]. Until the matching `@objectstack/service-automation` change lands,
+the built-in `assignment` executor still writes an envelope object into the
+variable verbatim and `notify` renders it as JSON. For a digest body today,
+call a registered function from a `script` node.
+
+[#14149]: https://github.com/objectstack-ai/objectstack/issues/14149
+
+</Callout>
+
 **Create Record:**
 
 ```typescript

content/docs/references/automation/builtin-node-config.mdx

@@ -7,8 +7,9 @@ description: Builtin Node Config protocol schemas
 
 Config contracts for the remaining flat builtins — the CRUD quartet
 (`get_record` / `create_record` / `update_record` / `delete_record`),
-`screen`, and `map` (#4045). Sibling of `io-node-config.zod.ts`
-(notify / http) and `control-flow.zod.ts` (loop / parallel / try_catch).
+`screen`, `map` (#4045) and, since #14149, `assignment`'s value contract.
+Sibling of `io-node-config.zod.ts` (notify / http) and `control-flow.zod.ts`
+(loop / parallel / try_catch).
 
 ## Provenance — written from the executors, not from the forms
 
@@ -58,11 +59,15 @@ finding is that a bespoke guard's detection generalizes for free the moment
 a default flips, while its PROSE does not, so the prose is copied to the new
 door rather than left behind at the old one.
 
+`assignment` is described by its VALUES, not by a key set (#14149): the
+canonical `assignments` map's keys are the author's variable names, and with
+no `assignments` wrapper the TOP-LEVEL config keys are (logic-nodes.ts), so
+`AssignmentConfigSchema` below declares one key and an open catchall and puts
+the contract on what a value may be. The form↔Zod ledger test still pins the
+descriptor's free-form `assignments` map as the openness it is; that pin and
+this contract describe the same surface from the two sides.
+
 Deliberately absent:
- - `assignment` — its config cannot be described by a fixed key set: with no
-   `assignments` wrapper the TOP-LEVEL config keys ARE the author's variable
-   names (logic-nodes.ts). The ledger test pins that exemption with its
-   reason instead of pretending a shape.
  - `decision` / `script` / `subflow` / `wait` / `connector_action` — the
    descriptor-schemaless class (config-schemas.test.ts). `wait` and
    `connector_action` keep their contracts in FlowNodeSchema's sibling
@@ -79,13 +84,47 @@ Deliberately absent:
 ## TypeScript Usage
 
 ```typescript
-import { CreateRecordConfigSchema, DeleteRecordConfigSchema, GetRecordConfigSchema, MapConfigSchema, ScreenConfigSchema, ScreenFieldConfigSchema, UpdateRecordConfigSchema } from '@objectstack/spec/automation';
-import type { CreateRecordConfig, DeleteRecordConfig, GetRecordConfig, MapConfig, ScreenConfig, ScreenFieldConfig, UpdateRecordConfig } from '@objectstack/spec/automation';
+import { AssignmentConfigSchema, AssignmentExpressionValueSchema, AssignmentValueSchema, CreateRecordConfigSchema, DeleteRecordConfigSchema, GetRecordConfigSchema, MapConfigSchema, ScreenConfigSchema, ScreenFieldConfigSchema, UpdateRecordConfigSchema } from '@objectstack/spec/automation';
+import type { AssignmentConfig, AssignmentExpressionValue, AssignmentValue, CreateRecordConfig, DeleteRecordConfig, GetRecordConfig, MapConfig, ScreenConfig, ScreenFieldConfig, UpdateRecordConfig } from '@objectstack/spec/automation';
 
 // Validate data
-const result = CreateRecordConfigSchema.parse(data);
+const result = AssignmentConfigSchema.parse(data);
 ```
 
+---
+
+## AssignmentConfig
+
+### Properties
+
+| Property | Type | Required | Description |
+| :--- | :--- | :--- | :--- |
+| **assignments** | `Record<string, any>` | optional | Variables to set: each key is a variable name, each value a `{token}` template, a CEL value envelope, or a literal |
+
+
+---
+
+## AssignmentExpressionValue
+
+CEL value envelope `{ dialect: 'cel', source }` — evaluated by the expression engine to the value the variable takes; the whole CEL stdlib (`joinNonEmpty`, …) is reachable
+
+### Properties
+
+| Property | Type | Required | Description |
+| :--- | :--- | :--- | :--- |
+| **dialect** | `'cel'` | ✅ |  |
+| **source** | `string` | optional |  |
+| **ast** | `any` | optional |  |
+| **meta** | `{ rationale?: string; generatedBy?: string }` | optional |  |
+
+
+---
+
+## AssignmentValue
+
+Value the variable takes: a string (`{token}` flow interpolation — a sole token keeps its type), a CEL value envelope `{ dialect: 'cel', source }` evaluated by the expression engine (the CEL stdlib such as `joinNonEmpty` is reachable), or any other literal
+
+
 ---
 
 ## CreateRecordConfig

content/docs/references/index.mdx

@@ -1,6 +1,6 @@
 ---
 title: Protocol Reference
-description: Every schema published by @objectstack/spec — 1589 schemas across 14 protocol modules
+description: Every schema published by @objectstack/spec — 1592 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/. */}
@@ -21,7 +21,7 @@ counts are sums of the rows they head. Regenerate with
 | :--- | ---: | ---: | :--- |
 | [AI Protocol](/docs/references/ai) | 11 | 66 | Agents, tools, skills, RAG and knowledge sources, model registry, conversations. |
 | [API Protocol](/docs/references/api) | 31 | 436 | REST contracts, endpoints, routing, realtime, batch, discovery. |
-| [Automation Protocol](/docs/references/automation) | 13 | 69 | Flows and their nodes, approvals, ETL pipelines, webhooks, state machines, execution records. |
+| [Automation Protocol](/docs/references/automation) | 13 | 72 | Flows and their nodes, approvals, ETL pipelines, webhooks, state machines, execution records. |
 | [Cloud Protocol](/docs/references/cloud) | 11 | 94 | Environments, packages and versions, marketplace, developer portal, tenancy. |
 | [Data Protocol](/docs/references/data) | 29 | 166 | Objects, fields, queries, filters, datasources and drivers — the ObjectQL layer. |
 | [Identity Protocol](/docs/references/identity) | 5 | 27 | Users and accounts, organizations, positions, SCIM provisioning. |
@@ -33,7 +33,7 @@ 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) | 36 | 291 | The runtime environment — logging, jobs, cache, metrics, notifications, i18n and compliance. |
 | [UI Protocol](/docs/references/ui) | 16 | 153 | Apps, pages, views, dashboards, reports, actions and themes — the ObjectUI layer. |
-| **Total** | **199** | **1589** | 14 protocol modules |
+| **Total** | **199** | **1592** | 14 protocol modules |
 
 ---
 
@@ -103,15 +103,15 @@ REST contracts, endpoints, routing, realtime, batch, discovery.
 
 ## Automation Protocol
 
-**Source:** `packages/spec/src/automation/` · **Import:** `@objectstack/spec/automation` · **13 pages, 69 schemas**
+**Source:** `packages/spec/src/automation/` · **Import:** `@objectstack/spec/automation` · **13 pages, 72 schemas**
 
 Flows and their nodes, approvals, ETL pipelines, webhooks, state machines, execution records.
 
 | File | Schemas |
 | :--- | :--- |
 | [`approval.zod.ts`](/docs/references/automation/approval) | `ApprovalDecision`, `ApprovalEscalation`, `ApprovalNodeApprover`, `ApprovalNodeConfig`, `ApproverType`, `DecisionOutputDef` |
 | [`bpmn-interop.zod.ts`](/docs/references/automation/bpmn-interop) | `BpmnDiagnostic`, `BpmnElementMapping`, `BpmnExportOptions`, `BpmnImportOptions`, `BpmnInteropResult`, `BpmnUnmappedStrategy`, `BpmnVersion` |
-| [`builtin-node-config.zod.ts`](/docs/references/automation/builtin-node-config) | `CreateRecordConfig`, `DeleteRecordConfig`, `GetRecordConfig`, `MapConfig`, `ScreenConfig`, `ScreenFieldConfig`, `UpdateRecordConfig` |
+| [`builtin-node-config.zod.ts`](/docs/references/automation/builtin-node-config) | `AssignmentConfig`, `AssignmentExpressionValue`, `AssignmentValue`, `CreateRecordConfig`, `DeleteRecordConfig`, `GetRecordConfig`, `MapConfig`, `ScreenConfig`, `ScreenFieldConfig`, `UpdateRecordConfig` |
 | [`control-flow.zod.ts`](/docs/references/automation/control-flow) | `FlowRegion`, `LoopConfig`, `ParallelBranch`, `ParallelConfig`, `RetryPolicy`, `TryCatchConfig`, `TryCatchErrorValue` |
 | [`execution.zod.ts`](/docs/references/automation/execution) | `Checkpoint`, `ConcurrencyPolicy`, `ExecutionError`, `ExecutionErrorSeverity`, `ExecutionLog`, `ExecutionStatus`, `ExecutionStepLog`, `ExecutionStepMetrics`, `ExecutionStepSkipReason`, `FlowRunGateSummary`, `FlowRunNodeSummary`, `FlowRunSummary`, `ScheduleState` |
 | [`flow.zod.ts`](/docs/references/automation/flow) | `Flow`, `FlowEdge`, `FlowNode`, `FlowNodeAction`, `FlowVariable`, `FlowVersionHistory` |

docs/audits/2026-07-unknown-key-strictness-ledger.counts.md

@@ -21,7 +21,7 @@ regenerate.
 | Measure | Value |
 |---|---|
 | Triaged directories | 5 |
-| Object sites in them | 439 |
+| Object sites in them | 440 |
 | Still-open (strip) sites | 124 |
 | Files carrying at least one | 22 |
 
@@ -46,10 +46,10 @@ The `strict` column is the one the campaign schedules against; it counts both th
 |---|---|---|---|---|---|
 | `ui/` | 169 | 157 | 5 | 0 | 7 |
 | `data/` | 157 | 76 | 1 | 0 | 80 |
-| `automation/` | 66 | 42 | 0 | 0 | 24 |
+| `automation/` | 67 | 42 | 0 | 1 | 24 |
 | `security/` | 20 | 7 | 0 | 0 | 13 |
 | `studio/` | 27 | 27 | 0 | 0 | 0 |
-| **total** | **439** | **309** | **6** | **0** | **124** |
+| **total** | **440** | **309** | **6** | **1** | **124** |
 
 ## File-level triage — site counts
 
@@ -115,7 +115,7 @@ classify and is not listed (it becomes reportable the day it grows its first sit
 |---|---|
 | `approval.zod.ts` | 4 |
 | `bpmn-interop.zod.ts` | 5 |
-| `builtin-node-config.zod.ts` | 8 |
+| `builtin-node-config.zod.ts` | 9 |
 | `control-flow.zod.ts` | 6 |
 | `execution.zod.ts` | 13 |
 | `flow-function.zod.ts` | 1 |
@@ -126,7 +126,7 @@ classify and is not listed (it becomes reportable the day it grows its first sit
 | `state-machine.zod.ts` | 6 |
 | `time-relative-trigger.zod.ts` | 1 |
 | `webhook.zod.ts` | 1 |
-| **total** | **66** |
+| **total** | **67** |
 
 ### `security/` — sites
 
@@ -204,7 +204,7 @@ over it is here.
 
 ### `automation/` — open
 
-**24 strip of 66**, in 5 file(s).
+**24 strip of 67**, in 5 file(s).
 
 | File | Strip | Sites |
 |---|---|---|
@@ -213,7 +213,7 @@ over it is here.
 | `execution.zod.ts` | 13 | 13 |
 | `flow.zod.ts` | 1 | 11 |
 | `node-executor.zod.ts` | 4 | 4 |
-| **total** | **24** | **66** |
+| **total** | **24** | **67** |
 
 | Bucket | Sites |
 |---|---|

packages/services/service-automation/src/builtin/config-expression-ledger.test.ts

@@ -46,6 +46,8 @@ interface SchemaNode {
   type?: string;
   properties?: Record<string, SchemaNode>;
   items?: SchemaNode;
+  /** `true` = an open map with untyped values; an object = the schema every value takes. */
+  additionalProperties?: boolean | SchemaNode;
   xExpression?: string;
 }
 
@@ -57,15 +59,26 @@ interface SchemaNode {
  * enforces the ADR-0032 §3 double-brace text template, a different dialect that
  * rejects a single `{x}`. Conflating the two would fail every valid
  * `loop.collection`.
+ *
+ * `'value'` (#14149) maps to the ledger's `value` role: a slot whose authored
+ * value may be a `{ dialect: 'cel', source }` envelope evaluated by the
+ * expression engine to a value — the `assignment` node's `assignments.*`. It
+ * IS `validateExpression`'s `'value'` role (CEL, any result type); what makes
+ * it a distinct ledger role is the slot's shape rule: only an envelope-shaped
+ * object is an expression there, a plain string stays `{var}` interpolation.
  */
 const ROLE_BY_MARKER: Record<string, FlowNodeExpressionRole> = {
   expression: 'predicate',
   template: 'flow-template',
+  value: 'value',
 };
 
 /**
  * Collect every `xExpression`-marked property in a configSchema, as the same
- * `key[].nested` path syntax the ledger uses.
+ * `key[].nested` path syntax the ledger uses — and, since #14149, the same
+ * `key.*` syntax: an object-valued `additionalProperties` is the schema every
+ * value of an open map takes, so a marker there declares "every authored key
+ * of this map", the sibling of `items` for arrays.
  */
 function collectExpressionProps(
   schema: SchemaNode | undefined,
@@ -88,6 +101,18 @@ function collectExpressionProps(
       else out.push(...collectExpressionProps(prop, here));
     }
   }
+
+  // An open map whose VALUES carry a schema contributes `key.*` — the ledger's
+  // spelling for "every authored key of this map" (`assignments.*`). A bare
+  // `additionalProperties: true` (untyped values — the `assignment`
+  // DESCRIPTOR's own shape) declares nothing, so the descriptor channel and
+  // the spec channel cannot double-declare the same slot.
+  const values = schema.additionalProperties;
+  if (values && typeof values === 'object') {
+    const here = prefix ? `${prefix}.*` : '*';
+    if (typeof values.xExpression === 'string') out.push({ path: here, marker: values.xExpression });
+    out.push(...collectExpressionProps(values, here));
+  }
   return out;
 }
 
@@ -203,6 +228,23 @@ describe('configSchema ↔ expression-ledger reconciliation (#4027)', () => {
     expect(declaredFromDescriptors().map(key)).not.toContain(key(decision!));
   });
 
+  it('assignment.assignments.* is covered — the #14149 value slot, declared where the descriptor cannot carry it', () => {
+    const assignment = FLOW_NODE_EXPRESSION_PATHS.find(
+      (e) => e.nodeType === 'assignment' && e.path === 'assignments.*',
+    );
+    expect(assignment, 'the ruled slot: an assignment value may be a CEL envelope').toBeDefined();
+    expect(assignment!.role).toBe('value');
+    // The descriptor declares `assignments` as `additionalProperties: true`
+    // (the openness IS its contract, pinned by the form↔Zod ledger), so the
+    // marker rides the spec Zod's map value and reaches this ratchet through
+    // the JSON map — never through the descriptor channel.
+    expect(declaredFromSchemalessConfigs().map(key)).toContain(key(assignment!));
+    expect(declaredFromDescriptors().map(key)).not.toContain(key(assignment!));
+    // And the marker is mapped, not merely tolerated: an unknown marker still
+    // fails `roleOf`, and a ledger entry with no declaration still reads stale.
+    expect(ROLE_BY_MARKER.value).toBe('value');
+  });
+
   it('screen.fields[].visibleWhen is covered — the #3528 regression', () => {
     const screen = FLOW_NODE_EXPRESSION_PATHS.find(
       (e) => e.nodeType === 'screen' && e.path === 'fields[].visibleWhen',