This record as markdown: /tools/karbassi-slack-mcp/apps-manifest-update.md
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 apps_manifest_update is rated Medium
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
The rule that runs apps_manifest_update safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Slack, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For apps_manifest_update, this is the rule to start with:
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.
The button opens the PolicyLayer dashboard: create your workspace, connect Slack, apply this rule, and every apps_manifest_update call is checked against it from then on.
Questions about apps_manifest_update
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.
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.
apps_manifest_update is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
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.
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.
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.
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