set_persona

Change the assistant

SERVERCoWork OS SOURCECoWork-OS/CoWork-OS

Medium RISK CLASS

Category Write

Parameters 00 required

Recommended Rate-limitedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/cowork-os/set-persona.md

WHAT IT DOES

What set_persona does on CoWork OS

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

RISK

Why set_persona is rated Medium

This tool modifies assistant behavior/personality settings, which is a reversible write operation. It doesn't delete data (not Destructive), execute arbitrary code (not Execute), or move money (not Financial). However, it ranks above Read because it creates or modifies persistent configuration state.

From the tool's definition Tool name 'set_persona' with description 'Change the assistant' indicates modification of system state/configuration.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs set_persona safely

PolicyLayer is an MCP gateway: it sits between your AI agents and CoWork OS, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For set_persona, this is the rule to start with:

set_persona Rate-limited

set_persona stays usable, but capped: an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "set_persona": {
      "limits": [
        {
          "counter": "set_persona_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect CoWork OS, apply this rule, and every set_persona call is checked against it from then on.

FAQ

Questions about set_persona

What does the set_persona tool do? +

Change the assistant. It is categorised as a Write tool in the CoWork OS MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on set_persona? +

Register the CoWork OS MCP server in PolicyLayer and add a rule for set_persona: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches CoWork OS. Nothing to install.

What risk level is set_persona? +

set_persona is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit set_persona? +

Yes. Add a rate_limit block to the set_persona rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block set_persona completely? +

Set action: deny in the PolicyLayer policy for set_persona. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides set_persona? +

set_persona is provided by the CoWork OS MCP server (CoWork-OS/CoWork-OS). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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