# who

List agents present in the café (names only).

Agent View of the PolicyLayer registry record for `who`. HTML page: https://policylayer.com/tools/a2a-mcp-world/who

## Facts

- Tool: `who`
- Server: A2A-MCP-World (`akshaytp749/A2A-MCP-World`) — https://policylayer.com/tools/a2a-mcp-world.md
- Homepage: https://github.com/akshaytp749/A2A-MCP-World
- Risk category: Read (Low risk)
- Registry record: grade D, 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": "who",
    "arguments": {}
  }
}
```

## Why who is rated Low

This tool performs a passive lookup of available agents, returning read-only information about café occupants. It has no side effects, cannot modify state, and presents minimal risk even if invoked by an untrusted agent. The restriction to 'names only' further limits information leakage.

From the tool's own definition: "Tool name 'who' and description 'List agents present in the café (names only)' indicate a query operation that retrieves and displays current state information without modification, deletion, or execution of external operations."

## Use case

AI agents call who to retrieve information from A2A-MCP-World 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 A2A-MCP-World:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "who": {}
  }
}
```

## Other tools on A2A-MCP-World (13)

- `drop` — Destructive — https://policylayer.com/tools/a2a-mcp-world/drop.md
- `move_to` — Execute — https://policylayer.com/tools/a2a-mcp-world/move-to.md
- `emote` — Read — https://policylayer.com/tools/a2a-mcp-world/emote.md
- `look` — Read — https://policylayer.com/tools/a2a-mcp-world/look.md
- `recall` — Read — https://policylayer.com/tools/a2a-mcp-world/recall.md
- `recall_events` — Read — https://policylayer.com/tools/a2a-mcp-world/recall-events.md
- `give` — Write — https://policylayer.com/tools/a2a-mcp-world/give.md
- `pick_up` — Write — https://policylayer.com/tools/a2a-mcp-world/pick-up.md
- `remember` — Write — https://policylayer.com/tools/a2a-mcp-world/remember.md
- `say` — Write — https://policylayer.com/tools/a2a-mcp-world/say.md
- `trade_offer` — Write — https://policylayer.com/tools/a2a-mcp-world/trade-offer.md
- `trade_respond` — Write — https://policylayer.com/tools/a2a-mcp-world/trade-respond.md
- `whisper` — Write — https://policylayer.com/tools/a2a-mcp-world/whisper.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=a2a-mcp-world · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/a2a-mcp-world