developer-1px · developer-1px · Sep 8, 2026 · Sep 8, 2026 · Sep 8, 2026 · Sep 8, 2026
diff --git a/docs/api-reference/json-document.md b/docs/api-reference/json-document.md
@@ -26,6 +26,11 @@ buildPointer(segments: ReadonlyArray<string | number>, options?: { readonly uriF
 ```ts
 createJSONDocument(initial: unknown, options?: JSONDocumentOptions): JSONDocument
 ```
+## `isJSONValue`
+
+```ts
+isJSONValue(value: unknown): value is JSONValue
+```
 ## `JSONAppliedChange`
 
 ```ts
@@ -167,6 +172,11 @@ type QueryResult =
       readonly reason?: string;
     };
 ```
+## `readPointer`
+
+```ts
+readPointer(value: JSONValue, pointer: Pointer): ReadResult
+```
 ## `ReadResult`
 
 ```ts

diff --git a/docs/public/api.md b/docs/public/api.md
@@ -158,6 +158,14 @@ import { jsonEqual } from "@interactive-os/json-document";
 jsonEqual({ title: "Draft", tags: [] }, { tags: [], title: "Draft" }); // true
 ```
 
+## 문서 없이 JSON 값 검증·조회하기
+
+Snapshot 조회와 일반 JSON 값 검증에는 `readPointer(value, pointer)`와
+`isJSONValue(value)`를 사용합니다. 두 함수는 값을 복제하거나 정규화하지
+않습니다. 주소 조회는 `document.at`과 같은 문법·실패 결과를 사용하고 원본
+참조를 반환합니다. 상세 제약과 예제는 [Core package 문서](https://github.com/developer-1px/json-document/blob/main/packages/json-document/README.md)의
+순수 core 항목에서 확인할 수 있습니다.
+
 ## 문서 없이 patch 적용하기
 
 `applyPatch(value, operations)`는 document 상태를 만들지 않고 RFC 6902
@@ -287,6 +295,8 @@ type Failure = {
 | --- | --- | --- |
 | 현재 값 | `document.value` | `JSONValue` |
 | 한 위치 읽기 | `document.at(pointer)` | `ReadResult` |
+| snapshot에서 한 위치 읽기 | `readPointer(value, pointer)` | `ReadResult` |
+| JSON 값 검사 | `isJSONValue(value)` | boolean/type guard |
 | 여러 위치 찾기 | `document.query(jsonPath)` | `QueryResult` |
 | patch 검사 | `document.validatePatch(operations)` | `JSONPatchValidationResult` |
 | 상태 변경 | `document.commit(operations, options?)` | `JSONDocumentCommitResult` |
@@ -298,13 +308,13 @@ type Failure = {
 
 ## 공개 export
 
-Package root는 다음 23개 symbol을 공개합니다.
+Package root는 다음 25개 symbol을 공개합니다.
 
 ```txt
 values
   applyPatch, createJSONDocument
   appendSegment, buildPointer, parentPointer, parsePointer
-  jsonEqual, parseArrayIndex, trackPointer, tryParsePointer
+  isJSONValue, jsonEqual, parseArrayIndex, readPointer, trackPointer, tryParsePointer
 
 types
   JSONValue, Pointer, JSONPatchOperation

diff --git a/docs/public/llms.txt b/docs/public/llms.txt
@@ -23,12 +23,13 @@ import {
 ```
 
 Root는 React, Zod, selection, clipboard, history, DOM을 import하지 않는다.
-공개 Root는 정확히 다음 23개 symbol이다.
+공개 Root는 정확히 다음 25개 symbol이다.
 
 ```txt
 values
   appendSegment, applyPatch, buildPointer, createJSONDocument
-  jsonEqual, parentPointer, parseArrayIndex, parsePointer, trackPointer, tryParsePointer
+  isJSONValue, jsonEqual, parentPointer, parseArrayIndex, parsePointer
+  readPointer, trackPointer, tryParsePointer
 
 types
   JSONAppliedChange, JSONPatchValidationResult

diff --git a/package-lock.json b/package-lock.json
diff --git a/packages/json-document-editing/src/clipboard.ts b/packages/json-document-editing/src/clipboard.ts
@@ -19,9 +19,3 @@ export function cutEditingClipboard<Payload, Result>(
 export function isClipboardRecord(value: unknown): value is Record<string, unknown> {
   return typeof value === "object" && value !== null && !Array.isArray(value);
 }
-
-export function isClipboardJSONValue(value: unknown): boolean {
-  if (value === null || typeof value === "string" || typeof value === "number" || typeof value === "boolean") return true;
-  if (Array.isArray(value)) return value.every(isClipboardJSONValue);
-  return isClipboardRecord(value) && Object.values(value).every(isClipboardJSONValue);
-}
diff --git a/packages/json-document-editing/src/database.ts b/packages/json-document-editing/src/database.ts
@@ -1,5 +1,6 @@
 import {
   buildPointer,
+  isJSONValue,
   jsonEqual,
   type JSONPatchOperation,
   type JSONValue,
@@ -13,7 +14,7 @@ import {
 import { resolveDocumentSource, type EditingDocumentSource } from "./document-source.js";
 import type { EditingHistoryOptions } from "./history.js";
 import { reconcileRangeSelection } from "./range-selection.js";
-import { isClipboardJSONValue, isClipboardRecord } from "./clipboard.js";
+import { isClipboardRecord } from "./clipboard.js";
 import { gridCellsInRange, gridPointIndex, gridPointKey, gridRangeBounds } from "./topology.js";
 import { acceptsDatabaseValue, defaultDatabaseValue } from "./database-property-value.js";
 import { assertDatabaseDocument, assertDatabaseView } from "./database-validation.js";
@@ -121,10 +122,10 @@ export interface DatabaseClipboard extends Record<string, JSONValue> {
 export const databaseClipboardFormat = {
   mimeType: "application/vnd.interactive-os.database+json" as const,
   parse(value: unknown): DatabaseClipboard | null {
-    if (!isClipboardRecord(value) || value.type !== this.mimeType || typeof value.text !== "string") return null;
+    if (!isJSONValue(value) || !isClipboardRecord(value) || value.type !== this.mimeType || typeof value.text !== "string") return null;
     if (!Array.isArray(value.cells) || value.cells.length === 0 || !Array.isArray(value.cells[0])) return null;
     const width = value.cells[0].length;
-    return width > 0 && value.cells.every((row) => Array.isArray(row) && row.length === width && row.every(isClipboardJSONValue))
+    return width > 0 && value.cells.every((row) => Array.isArray(row) && row.length === width)
       ? value as DatabaseClipboard : null;
   },
 };
@@ -341,6 +342,7 @@ function paste(
   topology?: DatabaseTopology,
   index?: DatabaseIndex,
 ): EditingResult<DatabaseSelection> {
+  if (!isJSONValue(clipboard)) return failure("clipboard.invalid");
   const focus = session.snapshot.selection.focus;
   if (focus === null) return failure("selection.empty");
   if (clipboard.cells.length === 0 || clipboard.cells.some((row) => row.length === 0)) {

diff --git a/packages/json-document-editing/src/sheet.ts b/packages/json-document-editing/src/sheet.ts
@@ -1,5 +1,6 @@
 import {
   buildPointer,
+  isJSONValue,
   type JSONPatchOperation,
   type JSONValue,
 } from "@interactive-os/json-document";
@@ -12,7 +13,7 @@ import {
 import { resolveDocumentSource, type EditingDocumentSource } from "./document-source.js";
 import type { EditingHistoryOptions } from "./history.js";
 import { reconcileRangeSelection, replaceRangeSelection } from "./range-selection.js";
-import { cutEditingClipboard, isClipboardJSONValue, isClipboardRecord } from "./clipboard.js";
+import { cutEditingClipboard, isClipboardRecord } from "./clipboard.js";
 import { gridCellsInRange, gridPointIndex, gridPointKey, gridRangeBounds, type GridTopology } from "./topology.js";
 import { assertSheetDocument, assertUniqueSheetIds } from "./sheet-validation.js";
 import {
@@ -74,10 +75,10 @@ export interface SheetClipboard extends Record<string, JSONValue> {
 export const sheetClipboardFormat = {
   mimeType: "application/vnd.interactive-os.sheet+json" as const,
   parse(value: unknown): SheetClipboard | null {
-    if (!isClipboardRecord(value) || value.type !== this.mimeType || typeof value.text !== "string") return null;
+    if (!isJSONValue(value) || !isClipboardRecord(value) || value.type !== this.mimeType || typeof value.text !== "string") return null;
     if (!Array.isArray(value.cells) || value.cells.length === 0 || !Array.isArray(value.cells[0])) return null;
     const width = value.cells[0].length;
-    return width > 0 && value.cells.every((row) => Array.isArray(row) && row.length === width && row.every(isClipboardJSONValue))
+    return width > 0 && value.cells.every((row) => Array.isArray(row) && row.length === width)
       ? value as SheetClipboard : null;
   },
 };
@@ -304,6 +305,7 @@ function paste(
   topology?: SheetTopology,
   index?: SheetIndex,
 ): EditingResult<SheetSelection> {
+  if (!isJSONValue(clipboard)) return failure("clipboard.invalid");
   const focus = session.snapshot.selection.focus;
   if (focus === null) return failure("selection.empty");
   if (clipboard.cells.length === 0 || clipboard.cells.some((row) => row.length === 0)) {

diff --git a/packages/json-document-editing/tests/clipboard-surface.test.ts b/packages/json-document-editing/tests/clipboard-surface.test.ts
@@ -1,13 +1,41 @@
 import { describe, expect, test } from "vitest";
+import { applyPatch, type JSONValue } from "@interactive-os/json-document";
 import {
   createDatabaseEditor,
   createDocumentEditor,
   createObjectEditor,
   createOrderEditor,
   createSheetEditor,
   createTreeEditor,
+  sheetClipboardFormat,
+  databaseClipboardFormat,
 } from "../src/index.js";
 
+describe.each([sheetClipboardFormat, databaseClipboardFormat])("$mimeType JSON boundary", (format) => {
+  const cycle: unknown[] = [];
+  cycle.push(cycle);
+  const invalidValues = [NaN, Infinity, new Date(0), Array(1), cycle, { nested: undefined }];
+
+  test.each(invalidValues.map((value, index) => ({ value, index })))("rejects non-JSON cell $index as Core does", ({ value }) => {
+    expect(applyPatch(null, [{ op: "replace", path: "", value: value as JSONValue }]).ok).toBe(false);
+    expect(format.parse({ type: format.mimeType, cells: [[value]], text: "x" })).toBeNull();
+  });
+
+  test("rejects holes in either matrix dimension and does not invoke cell accessors", () => {
+    let reads = 0;
+    const cell = Object.defineProperty({}, "value", { enumerable: true, get: () => { reads++; return 1; } });
+    for (const cells of [Array(1), [Array(1)], [[cell]]]) {
+      expect(format.parse({ type: format.mimeType, cells, text: "x" })).toBeNull();
+    }
+    expect(reads).toBe(0);
+  });
+
+  test("preserves valid nested JSON without normalization", () => {
+    const payload = { type: format.mimeType, cells: [[{ "a/b~": [1, true, null] }]], text: "x" };
+    expect(format.parse(payload)).toBe(payload);
+  });
+});
+
 describe("editing clipboard surface", () => {
   test("every domain editor copies a structured payload and a text projection", () => {
     const document = createDocumentEditor({ blocks: [{ id: "a", text: "A" }] });

diff --git a/packages/json-document-editing/tests/database-editor.test.ts b/packages/json-document-editing/tests/database-editor.test.ts
@@ -1,3 +1,4 @@
+import type { JSONValue } from "@interactive-os/json-document";
 import { describe, expect, test } from "vitest";
 import {
   acceptsDatabaseValue,
@@ -36,6 +37,28 @@ const initial: DatabaseDocument = {
 };
 
 describe("Database editor", () => {
+
+  test("rejects non-JSON paste before cloning and preserves selection, redo, and publication", () => {
+    const editor = createDatabaseEditor(initial);
+    expect(editor.dispatch({ type: "cell.commit", recordId: "r1", propertyId: "score", value: 9 }).ok).toBe(true);
+    expect(editor.undo().ok).toBe(true);
+    const before = editor.snapshot;
+    let publications = 0;
+    const unsubscribe = editor.subscribe(() => { publications++; });
+    const cycle: unknown[] = [];
+    cycle.push(cycle);
+    for (const value of [NaN, Infinity, new Date(0), Array(1), cycle, { nested: undefined }]) {
+      expect(editor.dispatch({
+        type: "clipboard.paste",
+        clipboard: { type: "application/vnd.interactive-os.database+json", cells: [[value as JSONValue]], text: "x" },
+      })).toMatchObject({ ok: false, code: "clipboard.invalid" });
+      expect(editor.snapshot).toEqual(before);
+    }
+    expect(publications).toBe(0);
+    expect(editor.snapshot.canRedo).toBe(true);
+    expect(editor.redo().ok).toBe(true);
+    unsubscribe();
+  });
   test("owns the canonical property value semantics", () => {
     const [, , score, status, done] = initial.schema.properties;
     expect(defaultDatabaseValue(score!)).toBe(0);

diff --git a/packages/json-document-editing/tests/sheet-editor.test.ts b/packages/json-document-editing/tests/sheet-editor.test.ts
@@ -1,3 +1,4 @@
+import type { JSONValue } from "@interactive-os/json-document";
 import { describe, expect, test } from "vitest";
 import { createSheetEditor, type SheetDocument } from "../src/index.js";
 
@@ -15,6 +16,28 @@ const initial: SheetDocument = {
 };
 
 describe("sheet editing vertical slice", () => {
+
+  test("rejects non-JSON paste before cloning and preserves selection, redo, and publication", () => {
+    const editor = createSheetEditor(initial);
+    expect(editor.dispatch({ type: "cell.commit", rowId: "r1", columnId: "score", value: 9 }).ok).toBe(true);
+    expect(editor.undo().ok).toBe(true);
+    const before = editor.snapshot;
+    let publications = 0;
+    const unsubscribe = editor.subscribe(() => { publications++; });
+    const cycle: unknown[] = [];
+    cycle.push(cycle);
+    for (const value of [NaN, Infinity, new Date(0), Array(1), cycle, { nested: undefined }]) {
+      expect(editor.dispatch({
+        type: "clipboard.paste",
+        clipboard: { type: "application/vnd.interactive-os.sheet+json", cells: [[value as JSONValue]], text: "x" },
+      })).toMatchObject({ ok: false, code: "clipboard.invalid" });
+      expect(editor.snapshot).toEqual(before);
+    }
+    expect(publications).toBe(0);
+    expect(editor.snapshot.canRedo).toBe(true);
+    expect(editor.redo().ok).toBe(true);
+    unsubscribe();
+  });
   test("selects a rectangular range and copies row-major JSON with TSV", () => {
     const editor = createSheetEditor(initial);
 

diff --git a/packages/json-document-rich-text-react/README.md b/packages/json-document-rich-text-react/README.md
@@ -6,6 +6,11 @@ scope whose copy text comes from the canonical Rich Text model projection.
 
 Official React renderer and `contenteditable` surface for the json-document Rich Text v1 profile.
 
+An editor's `pointer` may bind the root, a nested JSON Pointer, or its URI
+fragment form. The surface reads that snapshot through Core's `readPointer`
+without cloning the document. Escaped keys and fragment addresses retain the
+same rendering, change observation, and history behavior as ordinary pointers.
+
 `RichTextRenderer` renders canonical semantic HTML. `RichTextEditorSurface` connects that rendering to the official editor, DOM Selection, `beforeinput`, IME, Clipboard, and history integration.
 
 ```tsx

diff --git a/packages/json-document-rich-text-react/package.json b/packages/json-document-rich-text-react/package.json
@@ -29,12 +29,14 @@
     "verify": "npm run typecheck && npm test && npm run build"
   },
   "peerDependencies": {
+    "@interactive-os/json-document": "^3.0.0",
     "@interactive-os/json-document-react": "^0.1.0-rc.0",
     "@interactive-os/json-document-rich-text": "^0.1.0-rc.0",
     "@interactive-os/json-document-rich-text-web": "^0.1.0-rc.0",
     "react": "^18.0.0 || ^19.0.0"
   },
   "devDependencies": {
+    "@interactive-os/json-document": "*",
     "@interactive-os/json-document-react": "*",
     "@interactive-os/json-document-rich-text": "*",
     "@interactive-os/json-document-rich-text-web": "*",

diff --git a/packages/json-document-rich-text-react/src/render-store.ts b/packages/json-document-rich-text-react/src/render-store.ts
@@ -1,3 +1,4 @@
+import { buildPointer, parsePointer, readPointer, type JSONValue } from "@interactive-os/json-document";
 import {
   appliedOperationsFor,
   hasRichTextContent,
@@ -22,7 +23,7 @@ export interface RichTextRenderStore {
 }
 
 export function createRichTextRenderStore(editor: RichTextEditor): RichTextRenderStore {
-  const pointer = editor.pointer ?? "";
+  const pointer = buildPointer(parsePointer(editor.pointer ?? ""));
   let document = documentAtPointer(editor.snapshot.value, pointer);
   let blockIds: ReadonlyArray<string> = document.content.map((node) => node.id);
   let placeholderBlockId: string | null = null;
@@ -231,14 +232,10 @@ function relativeOperations(
   });
 }
 
-function documentAtPointer(value: unknown, pointer: string): RichTextDocument {
-  if (pointer === "") return value as RichTextDocument;
-  let current = value;
-  for (const segment of pointer.slice(1).split("/").map((part) => part.replaceAll("~1", "/").replaceAll("~0", "~"))) {
-    if (current === null || typeof current !== "object") throw new TypeError(`Rich Text document was not found at ${JSON.stringify(pointer)}.`);
-    current = (current as Readonly<Record<string, unknown>>)[segment];
-  }
-  return current as RichTextDocument;
+function documentAtPointer(value: JSONValue, pointer: string): RichTextDocument {
+  const result = readPointer(value, pointer);
+  if (!result.ok) throw new TypeError(`Rich Text document was not found at ${JSON.stringify(pointer)}.`);
+  return result.value as RichTextDocument;
 }
 
 function contentStructureChanged(

diff --git a/packages/json-document-rich-text-react/tests/render-locality.test.tsx b/packages/json-document-rich-text-react/tests/render-locality.test.tsx
@@ -2,7 +2,7 @@
 
 (globalThis as { IS_REACT_ACT_ENVIRONMENT?: boolean }).IS_REACT_ACT_ENVIRONMENT = true;
 
-import { createJSONDocument } from "@interactive-os/json-document";
+import { buildPointer, createJSONDocument } from "@interactive-os/json-document";
 import {
   createRichTextBlockFixture,
   createRichTextEditor,
@@ -20,6 +20,32 @@ import {
 import { createRichTextRenderStore } from "../src/render-store.js";
 
 describe("Rich Text React locality", () => {
+  it.each([false, true])("observes nested edits, history, and external changes (fragment: %s)", (uriFragment) => {
+    const key = "a/b~ #한";
+    const value = createRichTextBlockFixture(3, { idPrefix: "nested" });
+    const document = createJSONDocument({ [key]: value });
+    const pointer = buildPointer([key], { uriFragment });
+    const editor = createRichTextEditor({ document, pointer, selection: collapsed("nested-text-1", 1) });
+    const store = createRichTextRenderStore(editor);
+    let changed = 0;
+    const unsubscribe = store.subscribeNode("nested-text-1", () => { changed++; });
+    const untouched = store.getNode("nested-0");
+    expect(editor.dispatch({ type: "text.insert", text: "y" }).ok).toBe(true);
+    expect(changed).toBe(1);
+    expect(store.getNode("nested-text-1")).toMatchObject({ text: "xy" });
+    expect(store.getNode("nested-0")).toBe(untouched);
+    expect(lastRenderStoreBlockScan()).toBe(1);
+    expect(editor.undo().ok).toBe(true);
+    expect(store.getNode("nested-text-1")).toMatchObject({ text: "x" });
+    expect(editor.redo().ok).toBe(true);
+    expect(store.getNode("nested-text-1")).toMatchObject({ text: "xy" });
+    expect(document.commit([{ op: "replace", path: buildPointer([key, "content", 1, "content", 0, "text"]), value: "remote" }]).ok).toBe(true);
+    expect(store.getNode("nested-text-1")).toMatchObject({ text: "remote" });
+    expect(store.getNode("nested-0")).toBe(untouched);
+    expect(editor.pointer).toBe(pointer);
+    unsubscribe();
+  });
+
   it("catches up after disconnected structural and leaf edits", () => {
     const editor = createRichTextEditor({
       document: createJSONDocument(createRichTextBlockFixture(3, { idPrefix: "offline" })),