Unblock a card that was previously blocked (reversible). Restores card to ACTIVE status. Cannot be used on permanently CANCELED cards.
AI agents use unblock_card to create or update resources in Mcp Ap2 — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Mcp Ap2 environment.
This tool modifies the state of a payment card from blocked to active. It is explicitly reversible, so it does not qualify as Destructive. However, restoring a card to ACTIVE status has significant financial security implications — it re-enables spending capability on a card that was intentionally blocked.
From the tool's definition Unblock a card that was previously blocked (reversible). Restores card to ACTIVE status.
Documented attack patterns abuse exactly the kind of access unblock_card gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Mcp Ap2, and nothing reaches the server without passing your rules. This is the rule we recommend for unblock_card:
{
"version": "1",
"default": "deny",
"tools": {
"unblock_card": {
"limits": [
{
"counter": "unblock_card_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
} unblock_card 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.
Free to start. No card required.
Unblock a card that was previously blocked (reversible). Restores card to ACTIVE status. Cannot be used on permanently CANCELED cards. It is categorised as a Write tool in the Mcp Ap2 MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Mcp Ap2 MCP server in PolicyLayer and add a rule for unblock_card: 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 Mcp Ap2. Nothing to install.
unblock_card 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 unblock_card 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 unblock_card. 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.
unblock_card is provided by the Mcp Ap2 MCP server (@codespar/mcp-ap2). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Mcp Ap2, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
1300 Mcp Ap2 tools catalogued and risk-classified — across an index of 43,000+ MCP servers.