AI agents use update_message to create or update resources in Basecamp MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Basecamp MCP Server environment.
This tool modifies existing message content in Basecamp, which is a reversible write operation. It does not delete data (would be Destructive), execute arbitrary code (would be Execute), involve financial transactions (would be Financial), or retrieve data without modification (would be Read).
From the tool's definition Tool name 'update_message' and description 'Update an existing message' indicate modification of existing data.
Documented attack patterns abuse exactly the kind of access update_message gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Basecamp MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for update_message:
{
"version": "1",
"default": "deny",
"tools": {
"update_message": {
"limits": [
{
"counter": "update_message_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}update_message 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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Update an existing message. It is categorised as a Write tool in the Basecamp MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Basecamp MCP Server MCP server in PolicyLayer and add a rule for update_message: 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 Basecamp MCP Server. Nothing to install.
update_message 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 update_message 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 update_message. 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.
update_message is provided by the Basecamp MCP Server MCP server (qusaiisaleem/basecamp-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Basecamp MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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56 Basecamp MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.