marketplace-announce

Publish a kind 31402 service announcement on Nostr.

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/marketplace-announce.md

WHAT IT DOES

What marketplace-announce does on Nostr Bray

AI agents use marketplace-announce 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 marketplace-announce is rated Medium

This tool publishes a service announcement to the Nostr network, which is a write operation creating a new post/event. It is reversible in principle (the announcement can be deleted), so it falls under Write rather than Destructive. Severity is medium because a misused announcement could spread misinformation or spam to the network, but it does not directly destroy data or move funds.

From the tool's definition Publish a kind 31402 service announcement on Nostr

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs marketplace-announce 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 marketplace-announce, this is the rule to start with:

marketplace-announce Rate-limited

marketplace-announce 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": {
    "marketplace-announce": {
      "limits": [
        {
          "counter": "marketplace-announce_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 marketplace-announce call is checked against it from then on.

FAQ

Questions about marketplace-announce

What does the marketplace-announce tool do? +

Publish a kind 31402 service announcement on Nostr. 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 marketplace-announce? +

Register the Nostr Bray MCP server in PolicyLayer and add a rule for marketplace-announce: 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 marketplace-announce? +

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

Can I rate-limit marketplace-announce? +

Yes. Add a rate_limit block to the marketplace-announce 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 marketplace-announce completely? +

Set action: deny in the PolicyLayer policy for marketplace-announce. 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 marketplace-announce? +

marketplace-announce 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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