Patch title / tags / producer / providers after the fact. Safe to call multiple times; each call replaces the specified fields. Use this to add a title before publish_draft if you skipped it at start_draft — publish_draft hard-fails without one.
Part of the Prxhub server.
Free to start. No card required.
AI agents use set_metadata to create or modify resources in Prxhub. 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 set_metadata 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 Prxhub.
Write tools can modify data. A rate limit prevents runaway bulk operations from AI agents.
{
"version": "1",
"default": "deny",
"tools": {
"set_metadata": {
"limits": [
{
"counter": "set_metadata_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}See the full Prxhub policy for all 19 tools.
These attack patterns abuse exactly the kind of access set_metadata 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.
Patch title / tags / producer / providers after the fact. Safe to call multiple times; each call replaces the specified fields. Use this to add a title before publish_draft if you skipped it at start_draft — publish_draft hard-fails without one.. It is categorised as a Write tool in the Prxhub MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Prxhub MCP server in PolicyLayer and add a rule for set_metadata: 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 Prxhub. Nothing to install.
set_metadata 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 set_metadata 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 set_metadata. 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.
set_metadata is provided by the Prxhub MCP server (https://prxhub.com/api/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 19 Prxhub 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.