MCP Sampling

A server asking the client to run a model on its behalf. Sampling inverts the usual direction — the server sends the request, your model and your budget answer it — so the messages are shown verbatim before the buttons.

src/components/ui/mcp-sampling.tsx

About

From the component's own source, where it was written.

A server asking the client to run a model on its behalf.

MCP sampling inverts the usual direction: the server sends a request, and the *client's* model and the *client's* budget answer it. That inversion is the whole risk. A server you installed for its file search can ask for a completion, and unless the client shows the request, nobody sees the prompt that was sent or the tokens that were spent.

So the messages are shown verbatim, before the buttons, in the order the server proposed them — the same rule as ToolApproval, for the same reason. maxTokens is displayed because it is what the request will cost, and a request that omits it is flagged rather than defaulted quietly.

Approve is not the primary action by default. This is a server spending your budget on its own initiative; the emphasis belongs on reading it first.

Install

npx astralyx-ui add mcp-sampling

Usage

import { McpSampling } from '@/components/ui/mcp-sampling'

<McpSampling server="git" messages={request.messages} maxTokens={512} onApprove={run} onDeny={deny} />

Composer

Change the props and the source below follows.

Props

maxTokens set

tsx

<McpSampling
  server="git"
  messages={request.messages}
  maxTokens={512}
  onApprove={run}
  onDeny={deny}
/>

Examples

A server asking for a completion

tsx

<McpSampling server="git" messages={messages} maxTokens={512} />

API

Generated from the source, so it cannot fall behind the code. One table per exported component, then hooks, functions and types.

`McpSampling`

A server asking the client to run a model on its behalf.

Extends Omit<ComponentProps<'div'>, 'onSelect'>.

Prop	Type	Default	Description
server	string	required	The server making the request.
messages	SamplingMessage[]	required	Shown verbatim, in the server’s order, above the buttons. A server you installed for file search can ask for a completion; unless the client shows it, nobody sees what was sent.
intent	ReactNode	—	The server's stated intent, when it sends one.
maxTokens	number	—	What the request will cost. Absent is flagged as unbounded rather than defaulted quietly.
modelHint	string	—	Model preference hints from the request.
onApprove	() => void	—	—
onDeny	() => void	—	—
busy	boolean	false	—
approveLabel	string	'Run it'	—
denyLabel	string	'Deny'	—
messagesLabel	string	'Messages the server wants sent'	—
unboundedLabel	string	'No token ceiling requested'	—

Types

`SamplingMessage`

Field	Type	Description
role	'user' \| 'assistant' \| 'system'	—
content	string	—

Behaviour

Topic	Detail	Description
approve styling	secondary, not primary	This is a server spending your budget on its own initiative. The emphasis belongs on reading it first.