---
title: "Keep completion result members within MCP fields"
description: "The nested completion object is closed even when its surrounding result is open. It accepts values, total, and hasMore, not arbitrary pagination or vendor fields. Remove additional"
source: "https://mcpdesc.org/docs/rules/0.9.0-rc.3/mcp/completion-result-closed/"
---

The nested completion object is closed even when its surrounding result is open. It accepts values, total, and hasMore, not arbitrary pagination or vendor fields. Remove additional members or explicitly review a different metadata destination.

## Requirement

The completion object of a completion result contains only values, total, and hasMore.

## Details

**Rule ID:** `mcp.completion.result-closed`  
**Owner:** mcp  
**Surface:** CompleteResult · **Path:** `completion`  
**Kind:** structural  
**Requirement level:** must  
**Protocol versions:** independent of the MCP protocol version  
**Document schema locations:** `#/$defs/completionResult`  
**Status:** internal · **Enforcement:** internal

## Required by

* **MCP Description 0.9.0, Sections 10.4.6 and 11.4**  
  * 3\. Document Structure: [req-carried-nested-closed](https://mcpdesc.org/docs/specification/0.9.0-rc.3/document-structure#req-carried-nested-closed)
  * 1. Document Structure: [req-carried-closed-reject](https://mcpdesc.org/docs/specification/0.9.0-rc.3/document-structure#req-carried-closed-reject)

## Based on

* **Tier 1 — MCP schema.ts and normative specification text:** MCP 2024-11-05 to 2026-07-28 schema.ts, interface CompleteResult, completion (no index signature)  
  * [validation/mcp-schemas/2024-11-05/schema.ts#L974-L992](https://github.com/modelcontextprotocol/modelcontextprotocol/blob/dae694f61a31f7a3ec2af3aff709e11f70f61e48/schema/2024-11-05/schema.ts#L974-L992)
  * [validation/mcp-schemas/2025-03-26/schema.ts#L1115-L1133](https://github.com/modelcontextprotocol/modelcontextprotocol/blob/dae694f61a31f7a3ec2af3aff709e11f70f61e48/schema/2025-03-26/schema.ts#L1115-L1133)
  * [validation/mcp-schemas/2025-06-18/schema.ts#L1342-L1362](https://github.com/modelcontextprotocol/modelcontextprotocol/blob/dae694f61a31f7a3ec2af3aff709e11f70f61e48/schema/2025-06-18/schema.ts#L1342-L1362)
  * [validation/mcp-schemas/2025-11-25/schema.ts#L2037-L2057](https://github.com/modelcontextprotocol/modelcontextprotocol/blob/dae694f61a31f7a3ec2af3aff709e11f70f61e48/schema/2025-11-25/schema.ts#L2037-L2057)
  * [validation/mcp-schemas/2026-07-28/schema.ts#L2633-L2661](https://github.com/modelcontextprotocol/modelcontextprotocol/blob/dae694f61a31f7a3ec2af3aff709e11f70f61e48/schema/2026-07-28/schema.ts#L2633-L2661)

## Examples

### Valid example

Source: [expected-valid/named-completion-examples.json](https://github.com/mcpdesc/mcpdesc-specification/blob/v0.9.0-rc.3/spec/draft/fixtures/expected-valid/named-completion-examples.json) · Selected: `/resourceTemplates/0/completionExamples`

```json
{
  "issue-prefix": {
    "argument": {
      "name": "issue",
      "value": "12"
    },
    "result": {
      "completion": {
        "values": [
          "120",
          "121",
          "129"
        ],
        "hasMore": true,
        "total": 14
      }
    }
  }
}
```

### Invalid example

Source: [expected-invalid/completion-result-extra-field.json](https://github.com/mcpdesc/mcpdesc-specification/blob/v0.9.0-rc.3/spec/draft/fixtures/expected-invalid/completion-result-extra-field.json) · Selected: `/resourceTemplates/0/completionExamples/issue-prefix/result/completion`

```json
{
  "values": [
    "120",
    "121"
  ],
  "acmeRank": 1
}
```

## Rule Source Code

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