From 6297e3b3e090d8f4057d66da69e3cc5ce0d72ea0 Mon Sep 17 00:00:00 2001
From: Claude <noreply@anthropic.com>
Date: Tue, 18 Aug 2026 20:17:22 +0000
Subject: [PATCH] docs(blocks): teach a validation shape the input node
 actually declares (#5229)
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The "Add Validation" section of content/docs/blocks/forms.mdx taught a
`validation` object on a `"type": "input"` node, carrying a flat string
`pattern` and a sibling `message` key.

`InputSchema` declares no `validation` key at all, and `BaseSchema` is
`.passthrough()`, so the whole object rode through unvalidated: `objectui
validate` accepted it (it accepts `"validation": {"pattern": 12345,
"message": false}` just as happily), `InputRenderer` never reads
`schema.validation`, and form.tsx's #5099 diagnostic walks a form node's
`fields[]` rather than standalone input nodes. A reader copying the example
got zero validation and zero diagnostics from every tool we ship.

Replaced with the keys the node actually declares and the renderer actually
reads: `required` and `pattern` (a string), forwarded to the native HTML
input attributes at input.tsx:56. Added the `form` component's
`fields[].validation` route for rule objects with custom messages, in the
`{ value, message }` shape FieldConstraintsSchema pins, and stated why
`pattern` alone cannot come from JSON there — react-hook-form runs it only
when `value instanceof RegExp` — pointing at the field-metadata route and
the TypeScript form instead.

Swept the whole file: this was the only occurrence of the dialect.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RV6yuVCxymHYE16PL9vQkE
---
 content/docs/blocks/forms.mdx | 47 ++++++++++++++++++++++++++++++++---
 1 file changed, 43 insertions(+), 4 deletions(-)

diff --git a/content/docs/blocks/forms.mdx b/content/docs/blocks/forms.mdx
index c299981c10..da9be706f2 100644
--- a/content/docs/blocks/forms.mdx
+++ b/content/docs/blocks/forms.mdx
@@ -39,19 +39,58 @@ Customize form blocks for your application:
 
 ### Add Validation
 
+The blocks on this page are built from plain `input` nodes, and an `input`
+declares its own validation keys — `required`, `pattern`, `maxLength`, `min`,
+`max` and `step` — which the renderer forwards to the native HTML input
+attributes:
+
 ```json
 {
   "type": "input",
   "name": "email",
   "inputType": "email",
   "required": true,
-  "validation": {
-    "pattern": "^[a-z0-9._%+-]+@[a-z0-9.-]+\\.[a-z]{2,}$",
-    "message": "Please enter a valid email address"
-  }
+  "pattern": "^[a-z0-9._%+-]+@[a-z0-9.-]+\\.[a-z]{2,}$"
+}
+```
+
+`inputType: "email"` already gets the browser's own email check; `pattern`
+tightens it. The browser enforces these constraints when the input is submitted
+inside a `<form>`.
+
+An `input` node has **no `validation` key**. Rule objects with custom messages
+belong to the [form component](/docs/components/form/form), whose `fields[]`
+entries carry them. Every rule there is a `{ value, message }` object, and
+`validation.required` supplies the message only — whether the field is required
+is decided by `required` on the field itself:
+
+```json
+{
+  "type": "form",
+  "fields": [
+    {
+      "name": "message",
+      "type": "textarea",
+      "label": "How can we help?",
+      "required": true,
+      "validation": {
+        "required": "Please tell us how we can help",
+        "minLength": { "value": 20, "message": "Please use at least 20 characters" },
+        "maxLength": { "value": 2000, "message": "Please keep it under 2000 characters" }
+      }
+    }
+  ]
 }
 ```
 
+`pattern` is the one rule that route cannot take from JSON: react-hook-form runs
+it only when the rule's `value` is a compiled `RegExp`, and no JSON document can
+hold one. Declare the pattern on the object field's metadata instead (`pattern`,
+a string, which `@object-ui/fields` compiles before the rule reaches the form),
+or in a TypeScript-authored schema pass the real thing —
+`pattern: { value: /.../, message: '...' }`. The full rule table is in the
+[Form Plugin](/docs/plugins/plugin-form) reference.
+
 ### Add Submit Action
 
 ```json