relay-count
Count events matching a filter without fetching them (NIP-45). Sends a COUNT request to each relay. Falls back to fetch-and-count (capped at 1000) if the relay does not support NIP-45. Results show per-relay counts with fallback/estimated flags. Filter fields may be supplied either as top-level a...
This record as markdown: /tools/dev-forgesworn-bray/relay-count.md
What relay-count does on Nostr Bray
AI agents call relay-count to retrieve information from Nostr Bray without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
Why relay-count is rated Low
This tool performs a read-only count operation on Nostr relay events based on supplied filter criteria. While it may fetch events as a fallback mechanism when NIP-45 is unsupported, the core function is data retrieval with no side effects that could modify state, execute code, or cause irreversible changes. The fallback behavior (fetch-and-count capped at 1000) remains within read semantics.
From the tool's definition Tool description states it 'Count events matching a filter without fetching them' and 'Sends a COUNT request to each relay'. These are query/retrieval operations with no data modification, deletion, or execution of arbitrary code.
Attacks that exploit this kind of access
The rule that runs relay-count 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 relay-count, this is the rule to start with:
relay-count is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Nostr Bray, apply this rule, and every relay-count call is checked against it from then on.
Questions about relay-count
Count events matching a filter without fetching them (NIP-45). Sends a COUNT request to each relay. Falls back to fetch-and-count (capped at 1000) if the relay does not support NIP-45. Results show per-relay counts with fallback/estimated flags. Filter fields may be supplied either as top-level arguments or wrapped in a single. It is categorised as a Read tool in the Nostr Bray MCP Server, which means it retrieves data without modifying state.
Register the Nostr Bray MCP server in PolicyLayer and add a rule for relay-count: 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.
relay-count 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 relay-count 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 relay-count. 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.
relay-count 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.
More on Nostr Bray, and thousands of servers like it.
This server
Across the catalogue