> ## Documentation Index
> Fetch the complete documentation index at: https://docs.chatblocks.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Interactive block views

> Display published code blocks in clients that support MCP Apps.

`blocks.view` displays a published Chatblocks code block inside an MCP Apps-compatible chat client. Connect your workspace using the [agent setup guide](/mcp/setup), then ask your agent to list your published blocks and show one with `blocks.view`.

The tool accepts the block's opaque `id` from `blocks.list`. It is read-only, available on every signed-in plan, and only reads blocks owned by that API key's workspace. Anonymous playground keys do not expose this tool yet.

## Supported blocks

This first version supports self-contained native code blocks: HTML, CSS, JavaScript, and bundled assets, including interactive 3D scenes. Publish the block before displaying it.

External network access, third-party script imports, nested websites, stores, live-data widgets, workers, and code requiring dynamic evaluation are not supported in this view. Blocks that declare external network access or a platform-managed format return an explanation instead. Undeclared dependencies can still fail at runtime; this viewer is not an automatic compatibility test.

The block runs in a separate sandbox without access to the host's MCP tools, cookies, storage, forms, popups, or parent page. The host may impose additional restrictions.

## Client support

Clients without MCP Apps support receive a text response identifying the block and published version, with a link to the Chatblocks workspace. Support depends on the host, not on whether its MCP connection works.

The provider implements the stable [MCP Apps specification](https://github.com/modelcontextprotocol/ext-apps/blob/main/specification/2026-01-26/apps.mdx): `blocks.view` advertises `_meta.ui.resourceUri`, and the host fetches the HTML through authenticated `resources/read`. No API key is put in the HTML or a public URL.

This integration is separate from X Player Cards. It does not change X embedding or certify a website's runtime compatibility.

## Plugin packaging

OpenAI's current [plugin architecture](https://developers.openai.com/plugins/concepts/plugins) can package skills, an MCP connection, and optional MCP Apps UI together for ChatGPT and Codex. A Chatblocks plugin could make installation easier while keeping the same server. Chatblocks currently authenticates MCP requests with `cb_live_*` API keys; OpenAI’s [authenticated plugin flow](https://developers.openai.com/plugins/build/auth) expects MCP OAuth 2.1. OAuth onboarding and directory packaging are follow-up work, not shipped by this UI provider.

Public submission has separate [UI and nested-frame review requirements](https://developers.openai.com/plugins/build/chatgpt-ui). This viewer uses an opaque `srcdoc` child for isolation, declares no remote `frameDomains`, and has only been exercised in a local SDK host. Actual ChatGPT/Codex support and directory acceptance still require host-specific testing and review. Do not treat a working MCP connection or this local harness as approval for public distribution.


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