A brief and concise explanation of the hmr library. This tool provides information on how to use reactive programming or use hot module reloading in Python. As long as the user mentions HMR / Reactive Programming, this tool must be called first! Don't manually view the resource, call this tool in...
Part of the Hmr server.
Free to start. No card required.
AI agents call learn-hmr-basics to retrieve information from Hmr without modifying any data. This is common in research, monitoring, and reporting workflows where the agent needs context before taking action. Because read operations don't change state, they are generally safe to allow without restrictions -- but you may still want rate limits to control API costs.
Even though learn-hmr-basics only reads data, uncontrolled read access can leak sensitive information or rack up API costs. An agent caught in a retry loop could make thousands of calls per minute. A rate limit gives you a safety net without blocking legitimate use.
Read-only tools are safe to allow by default. No rate limit needed unless you want to control costs.
{
"version": "1",
"default": "deny",
"tools": {
"learn-hmr-basics": {}
}
} See the full Hmr policy for all 3 tools.
These attack patterns abuse exactly the kind of access learn-hmr-basics gives an agent. Each links to the full case and the policy that stops it:
Other read tools across the catalogue. The same approach applies to each: allow, with a rate cap to control cost.
A brief and concise explanation of the hmr library. This tool provides information on how to use reactive programming or use hot module reloading in Python. As long as the user mentions HMR / Reactive Programming, this tool must be called first! Don't manually view the resource, call this tool instead.. It is categorised as a Read tool in the Hmr MCP Server, which means it retrieves data without modifying state.
Register the Hmr MCP server in PolicyLayer and add a rule for learn-hmr-basics: 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 Hmr. Nothing to install.
learn-hmr-basics is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the learn-hmr-basics 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 learn-hmr-basics. 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.
learn-hmr-basics is provided by the Hmr MCP server (https://pyth-on-line.promplate.dev/hmr/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 3 Hmr tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
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