AI agents use add_holding to create or update resources in Crypto Portfolio — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Crypto Portfolio environment.
The 'add_holding' function creates or modifies portfolio data by adding new cryptocurrency positions. This is a Write operation as it reversibly creates data entries. Severity is medium because misuse could lead to incorrect portfolio records and poor investment decisions, but the effects are not irreversible (holdings can be removed) and no financial transactions occur.
From the tool's definition Tool name 'add_holding' indicates creation/modification of portfolio data. Server context describes 'managing cryptocurrency portfolio allocations,' and this tool's name suggests adding new cryptocurrency holdings to the portfolio.
Documented attack patterns abuse exactly the kind of access add_holding gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Crypto Portfolio, and nothing reaches the server without passing your rules. This is the rule we recommend for add_holding:
{
"version": "1",
"default": "deny",
"tools": {
"add_holding": {
"limits": [
{
"counter": "add_holding_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}add_holding 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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add_holding. It is categorised as a Write tool in the Crypto Portfolio MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Crypto Portfolio MCP server in PolicyLayer and add a rule for add_holding: 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 Crypto Portfolio. Nothing to install.
add_holding 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 add_holding 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 add_holding. 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.
add_holding is provided by the Crypto Portfolio MCP server (kukapay/crypto-portfolio-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Crypto Portfolio, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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4 Crypto Portfolio tools catalogued and risk-classified — across an index of 43,000+ MCP servers.