Register an agent with daily and weekly budget limits. Free tool - call this before using check_spend or report_spend. Upserts if agent already exists.
Part of the Zero Core Budget server.
Free to start. No card required.
AI agents use register_agent to create or modify resources in Zero Core Budget. Write operations carry medium risk because an autonomous agent could trigger bulk unintended modifications. Rate limits prevent a single agent session from making hundreds of changes in rapid succession. Argument validation ensures the agent passes expected values.
Without a policy, an AI agent could call register_agent repeatedly, creating or modifying resources faster than any human could review. PolicyLayer's rate limiting ensures write operations happen at a controlled pace, and argument validation catches malformed or unexpected inputs before they reach Zero Core Budget.
Write tools can modify data. A rate limit prevents runaway bulk operations from AI agents.
{
"version": "1",
"default": "deny",
"tools": {
"register_agent": {
"limits": [
{
"counter": "register_agent_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}See the full Zero Core Budget policy for all 6 tools.
These attack patterns abuse exactly the kind of access register_agent gives an agent. Each links to the full case and the policy that stops it:
Other write tools across the catalogue. The same approach applies to each: rate-limit and validate the arguments.
Register an agent with daily and weekly budget limits. Free tool - call this before using check_spend or report_spend. Upserts if agent already exists.. It is categorised as a Write tool in the Zero Core Budget MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Zero Core Budget MCP server in PolicyLayer and add a rule for register_agent: 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 Zero Core Budget. Nothing to install.
register_agent 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 register_agent 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 register_agent. 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.
register_agent is provided by the Zero Core Budget MCP server (@meltingpixels/zero-core-budget). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 6 Zero Core Budget tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
4,600+ MCP servers and 31,000+ tools scanned and risk-classified.