add yaml wire format and universal edit modes

.changeset/config.json

@@ -21,7 +21,8 @@
       "@json-render/mcp",
       "@json-render/svelte",
       "@json-render/solid",
-      "@json-render/react-three-fiber"
+      "@json-render/react-three-fiber",
+      "@json-render/yaml"
     ]
   ],
   "linked": [],

README.md

@@ -135,6 +135,7 @@ function Dashboard({ spec }) {
 | `@json-render/jotai`        | Jotai adapter for `StateStore`                                         |
 | `@json-render/xstate`       | XState Store (atom) adapter for `StateStore`                           |
 | `@json-render/mcp`          | MCP Apps integration for Claude, ChatGPT, Cursor, VS Code              |
+| `@json-render/yaml`         | YAML wire format with streaming parser, edit modes, AI SDK transform   |
 
 ## Renderers
 

apps/web/app/(main)/docs/api/core/page.mdx

@@ -76,6 +76,7 @@ interface PromptOptions {
   system?: string;           // Custom system message intro
   customRules?: string[];    // Additional rules to append
   mode?: "standalone" | "inline" | "generate" | "chat"; // Output mode (default: "standalone")
+  editModes?: EditMode[];    // Edit modes to document in prompt (default: ["patch"])
 }
 
 interface SpecValidationResult<T> {
@@ -480,9 +481,10 @@ function buildUserPrompt(options: UserPromptOptions): string
 
 interface UserPromptOptions {
   prompt: string;                        // The user's text prompt
-  currentSpec?: Spec | null;             // Existing spec to refine (triggers patch-only mode)
+  currentSpec?: Spec | null;             // Existing spec to refine (triggers edit mode)
   state?: Record<string, unknown> | null; // Runtime state context to include
   maxPromptLength?: number;              // Max length for user text (truncates before wrapping)
+  editModes?: EditMode[];                // Edit modes for refinement (default: ["patch"])
 }
 ```
 
@@ -492,14 +494,15 @@ interface UserPromptOptions {
 const userPrompt = buildUserPrompt({ prompt: "create a todo app" });
 ```
 
-### Refinement (patch-only mode)
+### Refinement (edit modes)
 
-When `currentSpec` is provided, the prompt instructs the AI to output only the patches needed for the change, not recreate the entire spec:
+When `currentSpec` is provided, the prompt instructs the AI to use the specified edit modes instead of recreating the entire spec. Available modes: `"patch"` (RFC 6902), `"merge"` (RFC 7396), and `"diff"` (unified diff).
 
 ```typescript
 const userPrompt = buildUserPrompt({
   prompt: "add a dark mode toggle",
   currentSpec: existingSpec,
+  editModes: ["patch", "merge"],
 });
 ```
 
@@ -514,6 +517,93 @@ const userPrompt = buildUserPrompt({
 });
 ```
 
+## Edit Modes
+
+Universal edit mode utilities for modifying existing specs. Used by `buildUserPrompt` internally and available for direct use.
+
+```typescript
+import {
+  buildEditInstructions,
+  buildEditUserPrompt,
+  isNonEmptySpec,
+  type EditMode,
+  type EditConfig,
+} from '@json-render/core';
+
+type EditMode = "patch" | "merge" | "diff";
+```
+
+### buildEditInstructions
+
+Generate the prompt section describing available edit modes. Supports both JSON and YAML formats.
+
+```typescript
+function buildEditInstructions(config: EditConfig, format: "json" | "yaml"): string
+
+const instructions = buildEditInstructions({ modes: ["patch", "merge"] }, "json");
+```
+
+### buildEditUserPrompt
+
+Build a user prompt for editing an existing spec. Includes the current spec (with line numbers when diff mode is enabled) and mode-specific instructions.
+
+```typescript
+function buildEditUserPrompt(options: BuildEditUserPromptOptions): string
+
+interface BuildEditUserPromptOptions {
+  prompt: string;
+  currentSpec?: Spec | null;
+  config?: EditConfig;
+  format: "json" | "yaml";
+  maxPromptLength?: number;
+  serializer?: (spec: Spec) => string;
+}
+```
+
+### isNonEmptySpec
+
+Check whether a value is a non-empty spec (has a root string and at least one element).
+
+```typescript
+function isNonEmptySpec(spec: unknown): spec is Spec
+```
+
+## Deep Merge and Diff
+
+Format-agnostic utilities for merging and diffing spec objects.
+
+### deepMergeSpec
+
+Deep-merge with RFC 7396 semantics: `null` deletes, arrays replace, objects recurse. Neither input is mutated.
+
+```typescript
+import { deepMergeSpec } from '@json-render/core';
+
+function deepMergeSpec(
+  base: Record<string, unknown>,
+  patch: Record<string, unknown>
+): Record<string, unknown>
+
+const merged = deepMergeSpec(currentSpec, { elements: { main: { props: { title: "New" } } } });
+```
+
+### diffToPatches
+
+Generate RFC 6902 JSON Patch operations that transform one object into another. Arrays are compared shallowly and replaced atomically; plain objects recurse.
+
+```typescript
+import { diffToPatches } from '@json-render/core';
+
+function diffToPatches(
+  oldObj: Record<string, unknown>,
+  newObj: Record<string, unknown>,
+  basePath?: string
+): JsonPatch[]
+
+const patches = diffToPatches(oldSpec, newSpec);
+// [{ op: "replace", path: "/elements/main/props/title", value: "New Title" }]
+```
+
 ## evaluateVisibility
 
 Evaluates a visibility condition against the state model.

apps/web/app/(main)/docs/api/yaml/page.mdx

@@ -0,0 +1,232 @@
+import { pageMetadata } from "@/lib/page-metadata"
+export const metadata = pageMetadata("docs/api/yaml")
+
+# @json-render/yaml
+
+YAML wire format for json-render. Progressive rendering and surgical edits via streaming YAML.
+
+## Prompt Generation
+
+### yamlPrompt
+
+Generate a YAML-format system prompt from any json-render catalog. Works with catalogs from any renderer.
+
+```typescript
+function yamlPrompt(
+  catalog: Catalog,
+  options?: YamlPromptOptions
+): string
+```
+
+```typescript
+import { yamlPrompt } from "@json-render/yaml";
+
+const systemPrompt = yamlPrompt(catalog, {
+  mode: "standalone",
+  customRules: ["Always use dark theme"],
+  editModes: ["merge"],
+});
+```
+
+### YamlPromptOptions
+
+<table>
+  <thead>
+    <tr>
+      <th>Option</th>
+      <th>Type</th>
+      <th>Default</th>
+      <th>Description</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <td><code>system</code></td>
+      <td><code>string</code></td>
+      <td><code>{'\"You are a UI generator that outputs YAML.\"'}</code></td>
+      <td>Custom system message intro</td>
+    </tr>
+    <tr>
+      <td><code>mode</code></td>
+      <td><code>{'\"standalone\" | \"inline\"'}</code></td>
+      <td><code>{'\"standalone\"'}</code></td>
+      <td>Standalone outputs only YAML; inline allows conversational responses with embedded YAML fences</td>
+    </tr>
+    <tr>
+      <td><code>customRules</code></td>
+      <td><code>{'string[]'}</code></td>
+      <td><code>{'[]'}</code></td>
+      <td>Additional rules appended to the prompt</td>
+    </tr>
+    <tr>
+      <td><code>editModes</code></td>
+      <td><code>{'EditMode[]'}</code></td>
+      <td><code>{'[\"merge\"]'}</code></td>
+      <td>Edit modes to document in the prompt (patch, merge, diff)</td>
+    </tr>
+  </tbody>
+</table>
+
+## AI SDK Transform
+
+### createYamlTransform
+
+Creates a `TransformStream` that intercepts AI SDK stream chunks and converts YAML spec/edit blocks into json-render patch data parts.
+
+```typescript
+function createYamlTransform(
+  options?: YamlTransformOptions
+): TransformStream<StreamChunk, StreamChunk>
+```
+
+Recognized fence types:
+
+- <code>{'```yaml-spec'}</code> -- Full YAML spec, parsed progressively
+- <code>{'```yaml-edit'}</code> -- Partial YAML, deep-merged with current spec
+- <code>{'```yaml-patch'}</code> -- RFC 6902 JSON Patch lines
+- <code>{'```diff'}</code> -- Unified diff against serialized spec
+
+### pipeYamlRender
+
+Convenience wrapper that pipes an AI SDK stream through the YAML transform. Drop-in replacement for `pipeJsonRender` from `@json-render/core`.
+
+```typescript
+function pipeYamlRender<T>(
+  stream: ReadableStream<T>,
+  options?: YamlTransformOptions
+): ReadableStream<T>
+```
+
+```typescript
+import { pipeYamlRender } from "@json-render/yaml";
+import { createUIMessageStream, createUIMessageStreamResponse } from "ai";
+
+const stream = createUIMessageStream({
+  execute: async ({ writer }) => {
+    writer.merge(pipeYamlRender(result.toUIMessageStream()));
+  },
+});
+return createUIMessageStreamResponse({ stream });
+```
+
+## Streaming Parser
+
+### createYamlStreamCompiler
+
+Create a streaming YAML compiler that incrementally parses YAML text and emits JSON Patch operations by diffing each successful parse against the previous snapshot.
+
+```typescript
+function createYamlStreamCompiler<T>(
+  initial?: Partial<T>
+): YamlStreamCompiler<T>
+```
+
+```typescript
+import { createYamlStreamCompiler } from "@json-render/yaml";
+
+const compiler = createYamlStreamCompiler<Spec>();
+
+compiler.push("root: main\n");
+compiler.push("elements:\n  main:\n    type: Card\n");
+
+const { result, newPatches } = compiler.flush();
+```
+
+### YamlStreamCompiler
+
+<table>
+  <thead>
+    <tr>
+      <th>Method</th>
+      <th>Returns</th>
+      <th>Description</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <td><code>push(chunk)</code></td>
+      <td><code>{'{ result: T; newPatches: JsonPatch[] }'}</code></td>
+      <td>Push a chunk of text, returns current result and new patches</td>
+    </tr>
+    <tr>
+      <td><code>flush()</code></td>
+      <td><code>{'{ result: T; newPatches: JsonPatch[] }'}</code></td>
+      <td>Flush remaining buffer, return final result</td>
+    </tr>
+    <tr>
+      <td><code>getResult()</code></td>
+      <td><code>T</code></td>
+      <td>Get the current compiled result</td>
+    </tr>
+    <tr>
+      <td><code>getPatches()</code></td>
+      <td><code>{'JsonPatch[]'}</code></td>
+      <td>Get all patches applied so far</td>
+    </tr>
+    <tr>
+      <td><code>reset(initial?)</code></td>
+      <td><code>void</code></td>
+      <td>Reset to initial state</td>
+    </tr>
+  </tbody>
+</table>
+
+## Fence Constants
+
+Exported string constants for fence detection in custom parsers:
+
+<table>
+  <thead>
+    <tr>
+      <th>Constant</th>
+      <th>Value</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <td><code>YAML_SPEC_FENCE</code></td>
+      <td><code>{'\"```yaml-spec\"'}</code></td>
+    </tr>
+    <tr>
+      <td><code>YAML_EDIT_FENCE</code></td>
+      <td><code>{'\"```yaml-edit\"'}</code></td>
+    </tr>
+    <tr>
+      <td><code>YAML_PATCH_FENCE</code></td>
+      <td><code>{'\"```yaml-patch\"'}</code></td>
+    </tr>
+    <tr>
+      <td><code>DIFF_FENCE</code></td>
+      <td><code>{'\"```diff\"'}</code></td>
+    </tr>
+    <tr>
+      <td><code>FENCE_CLOSE</code></td>
+      <td><code>{'\"```\"'}</code></td>
+    </tr>
+  </tbody>
+</table>
+
+## Re-exports from @json-render/core
+
+### diffToPatches
+
+Generate RFC 6902 JSON Patch operations that transform one object into another.
+
+```typescript
+function diffToPatches(
+  oldObj: Record<string, unknown>,
+  newObj: Record<string, unknown>,
+  basePath?: string
+): JsonPatch[]
+```
+
+### deepMergeSpec
+
+Deep-merge with RFC 7396 semantics: `null` deletes, arrays replace, objects recurse.
+
+```typescript
+function deepMergeSpec(
+  base: Record<string, unknown>,
+  patch: Record<string, unknown>
+): Record<string, unknown>
+```

apps/web/app/api/docs-chat/route.ts

@@ -16,8 +16,8 @@ const SYSTEM_PROMPT = `You are a helpful documentation assistant for json-render
 
 GitHub repository: https://github.com/vercel-labs/json-render
 Documentation: https://json-render.dev/docs
-npm packages: @json-render/core, @json-render/react, @json-render/vue, @json-render/svelte, @json-render/solid, @json-render/shadcn, @json-render/react-three-fiber, @json-render/react-native, @json-render/react-email, @json-render/react-pdf, @json-render/image, @json-render/remotion, @json-render/codegen, @json-render/mcp, @json-render/redux, @json-render/zustand, @json-render/jotai, @json-render/xstate
-Skills: json-render ships AI agent skills that teach coding agents how to use each package. Install with "npx skills add vercel-labs/json-render --skill <name>". Available skills: core, react, react-pdf, react-email, react-native, shadcn, react-three-fiber, image, remotion, vue, svelte, solid, codegen, mcp, redux, zustand, jotai, xstate. See /docs/skills for details.
+npm packages: @json-render/core, @json-render/react, @json-render/vue, @json-render/svelte, @json-render/solid, @json-render/shadcn, @json-render/react-three-fiber, @json-render/react-native, @json-render/react-email, @json-render/react-pdf, @json-render/image, @json-render/remotion, @json-render/codegen, @json-render/mcp, @json-render/redux, @json-render/zustand, @json-render/jotai, @json-render/xstate, @json-render/yaml
+Skills: json-render ships AI agent skills that teach coding agents how to use each package. Install with "npx skills add vercel-labs/json-render --skill <name>". Available skills: core, react, react-pdf, react-email, react-native, shadcn, react-three-fiber, image, remotion, vue, svelte, solid, codegen, mcp, redux, zustand, jotai, xstate, yaml. See /docs/skills for details.
 
 You have access to the full json-render documentation via the bash and readFile tools. The docs are available as markdown files in the /workspace/docs/ directory.