Mark a todo item as completed
AI agents use Mark-Todo-Done to create or update resources in Todos — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Todos environment.
This tool modifies data (changes a todo's completion status) but the change is reversible—the todo can be unmarked as done or updated back to pending status. This fits the Write category (creates or modifies data reversibly). The blast radius is minimal since completing a todo has no destructive, financial, or code-execution consequences.
From the tool's definition Tool name 'Mark-Todo-Done' and description 'Mark a todo item as completed' indicate modification of a todo item's status field from incomplete to complete.
Documented attack patterns abuse exactly the kind of access Mark-Todo-Done gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Todos, and nothing reaches the server without passing your rules. This is the rule we recommend for Mark-Todo-Done:
{
"version": "1",
"default": "deny",
"tools": {
"Mark-Todo-Done": {
"limits": [
{
"counter": "mark-todo-done_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}Mark-Todo-Done 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.
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Mark a todo item as completed. It is categorised as a Write tool in the Todos MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Todos MCP server in PolicyLayer and add a rule for Mark-Todo-Done: 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 Todos. Nothing to install.
Mark-Todo-Done 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 Mark-Todo-Done 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 Mark-Todo-Done. 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.
Mark-Todo-Done is provided by the Todos MCP server (tomelliot/todos-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Todos, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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11 Todos tools catalogued and risk-classified — across an index of 43,000+ MCP servers.