delete_thought

THE RISK

Critical Risk

Why delete_thought needs a policy

This tool permanently removes thoughts from TheBrain's hierarchical knowledge structure. Once deleted, the thought and its associated metadata cannot be recovered through normal means. This is a destructive operation that irreversibly eliminates user data.

From the tool's definition Tool is named "delete_thought" with description "Delete a thought" - the verb "delete" indicates irreversible removal of data from the knowledge management system.

Documented attack patterns abuse exactly the kind of access delete_thought gives an agent:

POLICY

How to control delete_thought

PolicyLayer is an MCP gateway — it sits between your AI agents and TheBrain MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for delete_thought:

policy.json

{
  "version": "1",
  "default": "deny",
  "hide": [
    "delete_thought"
  ]
}

delete_thought disappears from the agent's tool list entirely, and any attempt to call it is denied. The rest of the server keeps working.

Create a free account and register TheBrain MCP Server — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

RESTRICT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More TheBrain MCP Server tools

Destructive delete_attachment Delete an attachment Destructive delete_link Delete a link Write append_to_note Append content to an existing note Write add_file_attachment Add a file attachment (including images) to a thought Write add_url_attachment Add a URL attachment to a thought Write create_link Create a link between two thoughts with visual properties Write create_or_update_note Create or update a note with markdown content Write create_thought Create a new thought with optional visual properties

All 26 TheBrain MCP Server tools →

Destructive tools on other servers

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Go deeper

Critical-risk tools in TheBrain MCP Server → Every critical-risk tool this server exposes, in one view.
All critical-risk MCP tools → Every critical-risk tool across the catalogue, and the policy pattern that contains them.
The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Blast radius → How much damage one compromised or confused agent can do — and how to bound it.
Tool call approval → Approval gates on individual tool calls: auto-allow, prompt, or deny.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about delete_thought

What does the delete_thought tool do? +

Delete a thought. It is categorised as a Destructive tool in the TheBrain MCP Server MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.

How do I enforce a policy on delete_thought? +

Register the TheBrain MCP Server MCP server in PolicyLayer and add a rule for delete_thought: 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 TheBrain MCP Server. Nothing to install.

What risk level is delete_thought? +

delete_thought is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.

Can I rate-limit delete_thought? +

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

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

delete_thought is provided by the TheBrain MCP Server MCP server (redmorestudio/thebrain-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every TheBrain MCP Server tool call.

Start from TheBrain MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →