apps_manifest_update · Slack MCP: Risk & Policy

WHAT IT DOES

What apps_manifest_update does on Slack

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

WHY IT NEEDS A POLICY

Why apps_manifest_update needs a policy

Updating an app manifest is a reversible write operation that modifies application configuration. It does not delete data (so not Destructive) and does not move money (so not Financial). However, it is Write rather than Execute because the tool itself performs the update action rather than executing arbitrary code.

From the tool's definition The tool is named 'apps_manifest_update' and described as 'Update an app from an app manifest.' This updates application configuration/manifest, which modifies app behavior and settings.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

apps_manifest_update Rate-limited

apps_manifest_update 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": {
    "apps_manifest_update": {
      "limits": [
        {
          "counter": "apps_manifest_update_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

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PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Slack, so you can run agents against it safely.

FAQ

Questions about apps_manifest_update

What does the apps_manifest_update tool do? +

Update an app from an app manifest. It is categorised as a Write tool in the Slack MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on apps_manifest_update? +

Register the Slack MCP server in PolicyLayer and add a rule for apps_manifest_update: 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 Slack. Nothing to install.

What risk level is apps_manifest_update? +

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

Can I rate-limit apps_manifest_update? +

Yes. Add a rate_limit block to the apps_manifest_update 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 apps_manifest_update completely? +

Set action: deny in the PolicyLayer policy for apps_manifest_update. 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 apps_manifest_update? +

apps_manifest_update is provided by the Slack MCP server (karbassi/slack-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.