# UpdateOneMessageParticipant

A write tool on the Twenty MCP Server MCP server.

Agent View of the PolicyLayer registry record for `UpdateOneMessageParticipant`. HTML page: https://policylayer.com/tools/jdu278-twenty-mcp-server/updateonemessageparticipant

## Facts

- Tool: `UpdateOneMessageParticipant`
- Server: Twenty MCP Server (`jdu278/twenty-mcp-server`) — https://policylayer.com/tools/jdu278-twenty-mcp-server.md
- Homepage: https://github.com/Jdu278/twenty-mcp-server
- Risk category: Write (Medium risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 0
- Recommended policy verdict: Rate-limited

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "UpdateOneMessageParticipant",
    "arguments": {}
  }
}
```

## Why UpdateOneMessageParticipant is rated Medium

This tool modifies existing messageParticipant records within the Twenty CRM system. Update operations are classified as Write since they create or modify data reversibly.

From the tool's own definition: "Tool name contains 'UpdateOne' and description states 'Update One messageParticipant', indicating modification of existing CRM data (message participant records). The 'Update' action is reversible and does not delete data."

## Use case

AI agents use UpdateOneMessageParticipant to create or update resources in Twenty MCP Server, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Twenty MCP Server environment.

## Recommended policy (PolicyLayer)

Verdict: **Rate-limited**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Twenty MCP Server:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "UpdateOneMessageParticipant": {
      "limits": [
        {
          "counter": "updateonemessageparticipant_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}
```

## Other tools on Twenty MCP Server (218)

- `deleteOneAttachment` — Destructive — https://policylayer.com/tools/jdu278-twenty-mcp-server/deleteoneattachment.md
- `deleteOneBlocklist` — Destructive — https://policylayer.com/tools/jdu278-twenty-mcp-server/deleteoneblocklist.md
- `deleteOneCalendarChannel` — Destructive — https://policylayer.com/tools/jdu278-twenty-mcp-server/deleteonecalendarchannel.md
- `deleteOneCalendarChannelEventAssociation` — Destructive — https://policylayer.com/tools/jdu278-twenty-mcp-server/deleteonecalendarchanneleventassociation.md
- `deleteOneCalendarEvent` — Destructive — https://policylayer.com/tools/jdu278-twenty-mcp-server/deleteonecalendarevent.md
- `deleteOneCalendarEventParticipant` — Destructive — https://policylayer.com/tools/jdu278-twenty-mcp-server/deleteonecalendareventparticipant.md
- `deleteOneCompany` — Destructive — https://policylayer.com/tools/jdu278-twenty-mcp-server/deleteonecompany.md
- `deleteOneConnectedAccount` — Destructive — https://policylayer.com/tools/jdu278-twenty-mcp-server/deleteoneconnectedaccount.md
- `deleteOneFavorite` — Destructive — https://policylayer.com/tools/jdu278-twenty-mcp-server/deleteonefavorite.md
- `deleteOneFavoriteFolder` — Destructive — https://policylayer.com/tools/jdu278-twenty-mcp-server/deleteonefavoritefolder.md
- `deleteOneMessage` — Destructive — https://policylayer.com/tools/jdu278-twenty-mcp-server/deleteonemessage.md
- `deleteOneMessageChannel` — Destructive — https://policylayer.com/tools/jdu278-twenty-mcp-server/deleteonemessagechannel.md
- `deleteOneMessageChannelMessageAssociation` — Destructive — https://policylayer.com/tools/jdu278-twenty-mcp-server/deleteonemessagechannelmessageassociation.md
- `deleteOneMessageFolder` — Destructive — https://policylayer.com/tools/jdu278-twenty-mcp-server/deleteonemessagefolder.md
- `deleteOneMessageParticipant` — Destructive — https://policylayer.com/tools/jdu278-twenty-mcp-server/deleteonemessageparticipant.md
- `deleteOneMessageThread` — Destructive — https://policylayer.com/tools/jdu278-twenty-mcp-server/deleteonemessagethread.md
- `deleteOneNote` — Destructive — https://policylayer.com/tools/jdu278-twenty-mcp-server/deleteonenote.md
- `deleteOneNoteTarget` — Destructive — https://policylayer.com/tools/jdu278-twenty-mcp-server/deleteonenotetarget.md
- `deleteOneOpportunity` — Destructive — https://policylayer.com/tools/jdu278-twenty-mcp-server/deleteoneopportunity.md
- `deleteOnePerson` — Destructive — https://policylayer.com/tools/jdu278-twenty-mcp-server/deleteoneperson.md
- `deleteOneTask` — Destructive — https://policylayer.com/tools/jdu278-twenty-mcp-server/deleteonetask.md
- `deleteOneTaskTarget` — Destructive — https://policylayer.com/tools/jdu278-twenty-mcp-server/deleteonetasktarget.md
- `deleteOneTimelineActivity` — Destructive — https://policylayer.com/tools/jdu278-twenty-mcp-server/deleteonetimelineactivity.md
- `deleteOneView` — Destructive — https://policylayer.com/tools/jdu278-twenty-mcp-server/deleteoneview.md
- `deleteOneViewField` — Destructive — https://policylayer.com/tools/jdu278-twenty-mcp-server/deleteoneviewfield.md
- `deleteOneViewFilter` — Destructive — https://policylayer.com/tools/jdu278-twenty-mcp-server/deleteoneviewfilter.md
- `deleteOneWorkflow` — Destructive — https://policylayer.com/tools/jdu278-twenty-mcp-server/deleteoneworkflow.md
- `deleteOneWorkflowAutomatedTrigger` — Destructive — https://policylayer.com/tools/jdu278-twenty-mcp-server/deleteoneworkflowautomatedtrigger.md
- `deleteOneWorkflowRun` — Destructive — https://policylayer.com/tools/jdu278-twenty-mcp-server/deleteoneworkflowrun.md
- `deleteOneWorkflowVersion` — Destructive — https://policylayer.com/tools/jdu278-twenty-mcp-server/deleteoneworkflowversion.md
- …and 188 more: https://policylayer.com/tools/jdu278-twenty-mcp-server.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=jdu278-twenty-mcp-server · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/jdu278-twenty-mcp-server