# kb_show

Retrieve a single entry

Agent View of the PolicyLayer registry record for `kb_show`. HTML page: https://policylayer.com/tools/0x67108864-persistent-kb-mcp/kb-show

## Facts

- Tool: `kb_show`
- Server: Persistent Kb (`0x67108864/persistent-kb-mcp`) — https://policylayer.com/tools/0x67108864-persistent-kb-mcp.md
- Homepage: https://github.com/0x67108864/persistent-kb-mcp
- 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": "kb_show",
    "arguments": {}
  }
}
```

## Why kb_show is rated Low

This tool queries and returns a single knowledge base entry from the persistent SQLite knowledge base. It performs a read-only operation with no side effects, matching the Read category definition of retrieves or queries data.

From the tool's own definition: "Tool name 'kb_show' and description 'Retrieve a single entry' indicate a retrieval operation with no modification or deletion."

## Use case

AI agents call kb_show to retrieve information from Persistent Kb 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 Persistent Kb:

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

## Other tools on Persistent Kb (4)

- `kb_list` — Read — https://policylayer.com/tools/0x67108864-persistent-kb-mcp/kb-list.md
- `kb_search` — Read — https://policylayer.com/tools/0x67108864-persistent-kb-mcp/kb-search.md
- `kb_add` — Write — https://policylayer.com/tools/0x67108864-persistent-kb-mcp/kb-add.md
- `kb_tag` — Write — https://policylayer.com/tools/0x67108864-persistent-kb-mcp/kb-tag.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=0x67108864-persistent-kb-mcp · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/0x67108864-persistent-kb-mcp