Manifest

Every block has a chatblocks.json manifest at the root of its file set. The manifest is the contract between your code and the platform: it declares the format, the canvas footprint, what data flows in, and what the iframe is allowed to do. The full Zod schema lives in packages/shared/src/manifest.ts. This page covers the shape; the schema there is the source of truth and what the server validates against.

Minimal manifest

A barebones code block with no widget or data binding:

{
  "schemaVersion": 1,
  "format": "code",
  "entry": "src/App.tsx",
  "defaultSize": { "width": 320, "height": 200 }
}

That’s all that’s required. Everything else has sensible defaults.

Top-level fields

Field	Type	Required	Notes
`schemaVersion`	`1`	yes	Currently always `1`. Schema bumps go through a coordinated migration.
`format`	`"code"` \| `"embed"`	no (defaults to `"code"`)	See Formats.
`entry`	string	yes for `code`, must be absent for `embed`	Relative path ending in `.js`, `.jsx`, `.ts`, `.tsx`, or `.html`. No URLs, absolute paths, parent traversal, or backslashes.
`defaultSize`	`{ width, height }`	yes	Canvas footprint in pixels. Each dimension is an integer in `[50, 2000]`.
`constraints`	object	no	Min/max resize bounds. Defaults to 0.6×/2.5× of `defaultSize`, clamped to `[50, 2000]`.
`resizable`	boolean	no (defaults `true`)	Set `false` for fixed-shape blocks like a stamp or a specific-aspect-ratio widget.
`permissions`	array	no (defaults `[]`)	See Permissions.
`network`	object	no	`{ allowedOrigins: [] }`. Required when `"network"` permission is declared.
`embed`	object	yes for `embed`, must be absent for `code`	See Formats.

Formats

New blocks use the code or embed format. Legacy store manifests remain parseable.

code
embed

Vibe-coded block. Your file set is built into an iframe-loaded artifact via Vercel Sandbox. Strict CSP, no cross-origin framing, sandboxed iframe.Required: entry must be a relative path to a file in your set. Conventional: src/App.tsx.

{
  "schemaVersion": 1,
  "format": "code",
  "entry": "src/App.tsx",
  "defaultSize": { "width": 320, "height": 200 }
}

First-class live-website embed. The manifest declares a URL; the platform renders a fixed sandboxed iframe shell pointing at it. URL is visible in the block chrome and probed for framability at publish time.Required: embed.url (HTTPS, public hostname, no credentials). Optional: embed.sandbox ("scripts-only" default, or "strict" for no JS).

{
  "schemaVersion": 1,
  "format": "embed",
  "defaultSize": { "width": 600, "height": 400 },
  "embed": {
    "url": "https://example.com/dashboard",
    "sandbox": "scripts-only"
  }
}

Embed blocks can’t declare permissions or network.allowedOrigins — the embedded site manages its own network, and the iframe sandbox is platform-enforced.

Permissions

Declare the capabilities your code block needs. Each is opt-in.

Permission	Grants
`viewer.profile`	Read the viewer’s display name and avatar (when permitted by visibility).
`storage.kv`	Per-block key/value storage scoped to the viewer.
`assets`	Upload and serve static assets via Convex storage.
`events`	Emit custom events into the audit log.
`forms`	Render `<form>` elements with submission posting back to the platform.
`network`	Make outbound HTTP requests. Requires `network.allowedOrigins` to be set.

The network permission and network.allowedOrigins are coupled — declaring one without the other is a validation error. Origins must be HTTPS, origin-only (no path/query/hash/credentials, no wildcards).

{
  "permissions": ["network"],
  "network": {
    "allowedOrigins": ["https://api.example.com"]
  }
}

Constraints reference

constraints.min* and constraints.max* set the block’s resize bounds on a canvas. Defaults are derived from defaultSize:

min* = defaultSize.* × 0.6, clamped to ≥ 50.
max* = defaultSize.* × 2.5, clamped to ≤ 2000.

Override explicitly when your block has a tighter aesthetic range:

{
  "defaultSize": { "width": 320, "height": 200 },
  "constraints": {
    "minWidth": 280,
    "minHeight": 160,
    "maxWidth": 500,
    "maxHeight": 320
  }
}

The validator enforces min ≤ max for each axis, and defaultSize must lie within [min, max].

Validation errors

When validation fails, the API returns a list of issues, each with a stable code:

Code	Meaning
`missing_entry`	`code` format requires `entry`.
`invalid_entry`	`entry` path failed the relative-path / extension check.
`unexpected_entry`	`embed` format must not declare `entry`.
`missing_embed`	`embed` format requires `embed.url`.
`invalid_embed_url`	URL is not HTTPS, has credentials, or has a non-public hostname.
`unexpected_embed`	`code` format must not declare `embed`.
`invalid_constraint`	`min > max` on width or height.
`default_size_out_of_bounds`	`defaultSize` falls outside `constraints`.
`duplicate_permission`	Same permission listed twice.
`missing_network_permission`	`network.allowedOrigins` declared without the `"network"` permission.
`missing_network_origins`	`"network"` permission declared without any origins.
`invalid_origin`	An origin failed the HTTPS-origin-only check.
`unsupported_permissions`	`embed` format must not declare permissions.
`unsupported_network`	`embed` format must not declare `network.allowedOrigins`.
`unrecognized_field`	Unknown top-level field.

What’s next

Runtime

What happens at render time — render paths, sandbox, data injection.

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Concepts

Authoring blocks

MCP server