---
title: "Review deprecated client requirements"
description: "Some client capability forms remain recognized but are deprecated in later MCP protocol versions. The warning does not invalidate the document. Review the requirement against the s"
source: "https://mcpdesc.org/docs/rules/0.9.0-rc.3/mcp/client-capabilities-deprecated/"
---

Some client capability forms remain recognized but are deprecated in later MCP protocol versions. The warning does not invalidate the document. Review the requirement against the selected protocol version rather than assuming an older advertisement model still applies.

## Requirement

A client capability requirement that the applicable protocol version deprecates is reported.

## Details

**Rule ID:** `mcp.client-capabilities.deprecated`  
**Owner:** mcp  
**Surface:** ClientCapabilities · **Path:** `clientRequirements`  
**Kind:** semantic  
**Requirement level:** should  
**Status:** internal · **Enforcement:** internal

## Protocol version applicability

| 2024-11-05     | 2025-03-26     | 2025-06-18     | 2025-11-25 | 2026-07-28 |
| -------------- | -------------- | -------------- | ---------- | ---------- |
| not-applicable | not-applicable | not-applicable | applies    | applies    |

## Required by

* **MCP Description 0.9.0, Section 8.5**  
  * 8\. Capabilities: [req-client-requirements-deprecated](https://mcpdesc.org/docs/specification/0.9.0-rc.3/capabilities#req-client-requirements-deprecated)

## Based on

* **Tier 1 — MCP schema.ts and normative specification text:** MCP 2025-11-25 schema.ts, CreateMessageRequest includeContext (“thisServer” and “allServers” are soft-deprecated; tied to ClientCapabilities.sampling.context)  
  * [validation/mcp-schemas/2025-11-25/schema.ts#L1588-L1595](https://github.com/modelcontextprotocol/modelcontextprotocol/blob/dae694f61a31f7a3ec2af3aff709e11f70f61e48/schema/2025-11-25/schema.ts#L1588-L1595)
* **Tier 1 — MCP schema.ts and normative specification text:** MCP 2026-07-28 schema.ts, ClientCapabilities roots and sampling (@deprecated, SEP-2577)  
  * [validation/mcp-schemas/2026-07-28/schema.ts#L732-L732](https://github.com/modelcontextprotocol/modelcontextprotocol/blob/dae694f61a31f7a3ec2af3aff709e11f70f61e48/schema/2026-07-28/schema.ts#L732-L732)
  * [validation/mcp-schemas/2026-07-28/schema.ts#L733-L759](https://github.com/modelcontextprotocol/modelcontextprotocol/blob/dae694f61a31f7a3ec2af3aff709e11f70f61e48/schema/2026-07-28/schema.ts#L733-L759)

## Examples

### Accepted with a warning

Source: [expected-warning/deprecated-client-capability-requirements.json](https://github.com/mcpdesc/mcpdesc-specification/blob/v0.9.0-rc.3/spec/draft/fixtures/expected-warning/deprecated-client-capability-requirements.json) · Selected: `/prompts/0/clientRequirements`

```json
{
  "sampling": {
    "context": {}
  },
  "extensions": {
    "io.modelcontextprotocol/future-capability": {}
  }
}
```

## Rule Source Code

[capabilities.yaml](https://github.com/mcpdesc/mcpdesc-specification/blob/v0.9.0-rc.3/spec/draft/validation/rules/capabilities.yaml) at immutable tag [v0.9.0-rc.3](https://github.com/mcpdesc/mcpdesc-specification/blob/v0.9.0-rc.3/spec/draft).