handler-publish

SERVERNostr Bray SOURCEnostr-bray

Medium RISK CLASS

Category Write

Parameters 00 required

Recommended Rate-limitedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/dev-forgesworn-bray/handler-publish.md

WHAT IT DOES

What handler-publish does on Nostr Bray

AI agents use handler-publish to create or update resources in Nostr Bray, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Nostr Bray environment.

RISK

Why handler-publish is rated Medium

This tool creates and publishes metadata about MCP server endpoints on a distributed network. While the action modifies the network state, it is reversible and does not delete data or execute arbitrary code. The severity is medium because a compromised agent could advertise malicious MCP servers or inject false handler information, potentially directing other agents to untrusted endpoints.

From the tool's definition Tool description states: 'Publish a NIP-XX Machine Application Handler card (kind 31990)' — this creates and publishes a new event/record on the Nostr network.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs handler-publish safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Nostr Bray, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For handler-publish, this is the rule to start with:

handler-publish Rate-limited

handler-publish 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.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "handler-publish": {
      "limits": [
        {
          "counter": "handler-publish_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Nostr Bray, apply this rule, and every handler-publish call is checked against it from then on.

FAQ

Questions about handler-publish

What does the handler-publish tool do? +

Publish a NIP-XX Machine Application Handler card (kind 31990) advertising MCP transport endpoints. Lets other agents and tools discover MCP servers on Nostr by the event kinds they support. Provide at least one of stdio_command or http_url. It is categorised as a Write tool in the Nostr Bray MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on handler-publish? +

Register the Nostr Bray MCP server in PolicyLayer and add a rule for handler-publish: 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 Nostr Bray. Nothing to install.

What risk level is handler-publish? +

handler-publish is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit handler-publish? +

Yes. Add a rate_limit block to the handler-publish 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.

How do I block handler-publish completely? +

Set action: deny in the PolicyLayer policy for handler-publish. 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.

What MCP server provides handler-publish? +

handler-publish is provided by the Nostr Bray MCP server (nostr-bray). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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