# key-public

Derive a public key (hex + npub) from a secret key (nsec or hex). WARNING: the secret key is transmitted through the MCP transport — use only for local/trusted setups.

Agent View of the PolicyLayer registry record for `key-public`. HTML page: https://policylayer.com/tools/dev-forgesworn-bray/key-public

## Facts

- Tool: `key-public`
- Server: Nostr Bray (`nostr-bray`) — https://policylayer.com/tools/dev-forgesworn-bray.md
- Install: `npx -y nostr-bray`
- Homepage: https://github.com/forgesworn/bray
- Risk category: Read (Low risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 0
- Recommended policy verdict: Allowed

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "key-public",
    "arguments": {}
  }
}
```

## Why key-public is rated Low

This tool performs deterministic key derivation (a one-way mathematical operation on input to produce output) with no side effects on data or external systems. It is categorized as Read because it retrieves computed cryptographic material.

From the tool's own definition: "Tool 'derives' a public key from a secret key — it retrieves/computes and returns cryptographic data without modifying, deleting, or executing external operations."

## Use case

AI agents call key-public 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.

## Recommended policy (PolicyLayer)

Verdict: **Allowed**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Nostr Bray:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "key-public": {}
  }
}
```

## Other tools on Nostr Bray (239)

- `blossom-delete` — Destructive — https://policylayer.com/tools/dev-forgesworn-bray/blossom-delete.md
- `group-remove-user` — Destructive — https://policylayer.com/tools/dev-forgesworn-bray/group-remove-user.md
- `label-remove` — Destructive — https://policylayer.com/tools/dev-forgesworn-bray/label-remove.md
- `marketplace-credentials-clear` — Destructive — https://policylayer.com/tools/dev-forgesworn-bray/marketplace-credentials-clear.md
- `marketplace-retire` — Destructive — https://policylayer.com/tools/dev-forgesworn-bray/marketplace-retire.md
- `social-delete` — Destructive — https://policylayer.com/tools/dev-forgesworn-bray/social-delete.md
- `tombstone` — Destructive — https://policylayer.com/tools/dev-forgesworn-bray/tombstone.md
- `trust-revoke` — Destructive — https://policylayer.com/tools/dev-forgesworn-bray/trust-revoke.md
- `vault-revoke` — Destructive — https://policylayer.com/tools/dev-forgesworn-bray/vault-revoke.md
- `zap-wallet-clear` — Destructive — https://policylayer.com/tools/dev-forgesworn-bray/zap-wallet-clear.md
- `cast-spell` — Execute — https://policylayer.com/tools/dev-forgesworn-bray/cast-spell.md
- `execute-action` — Execute — https://policylayer.com/tools/dev-forgesworn-bray/execute-action.md
- `identity-restore-shamir` — Execute — https://policylayer.com/tools/dev-forgesworn-bray/identity-restore-shamir.md
- `identity-switch` — Execute — https://policylayer.com/tools/dev-forgesworn-bray/identity-switch.md
- `marketplace-probe` — Execute — https://policylayer.com/tools/dev-forgesworn-bray/marketplace-probe.md
- `nip44-encrypt` — Execute — https://policylayer.com/tools/dev-forgesworn-bray/nip44-encrypt.md
- `onboard-verified` — Execute — https://policylayer.com/tools/dev-forgesworn-bray/onboard-verified.md
- `relay-auth` — Execute — https://policylayer.com/tools/dev-forgesworn-bray/relay-auth.md
- `trust-attest-chain` — Execute — https://policylayer.com/tools/dev-forgesworn-bray/trust-attest-chain.md
- `trust-ring-lsag-sign` — Execute — https://policylayer.com/tools/dev-forgesworn-bray/trust-ring-lsag-sign.md
- `trust-ring-prove` — Execute — https://policylayer.com/tools/dev-forgesworn-bray/trust-ring-prove.md
- `trust-spoken-verify` — Execute — https://policylayer.com/tools/dev-forgesworn-bray/trust-spoken-verify.md
- `vault-encrypt` — Execute — https://policylayer.com/tools/dev-forgesworn-bray/vault-encrypt.md
- `marketplace-pay` — Financial — https://policylayer.com/tools/dev-forgesworn-bray/marketplace-pay.md
- `zap-make-invoice` — Financial — https://policylayer.com/tools/dev-forgesworn-bray/zap-make-invoice.md
- `zap-send` — Financial — https://policylayer.com/tools/dev-forgesworn-bray/zap-send.md
- `article-list` — Read — https://policylayer.com/tools/dev-forgesworn-bray/article-list.md
- `article-read` — Read — https://policylayer.com/tools/dev-forgesworn-bray/article-read.md
- `badge-list` — Read — https://policylayer.com/tools/dev-forgesworn-bray/badge-list.md
- `blossom-check` — Read — https://policylayer.com/tools/dev-forgesworn-bray/blossom-check.md
- …and 209 more: https://policylayer.com/tools/dev-forgesworn-bray.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=dev-forgesworn-bray · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/dev-forgesworn-bray