# at_witness

Witness signature for constitutive elevation. Sophia writes a foundational memory and self-attests; Yu invokes this to co-sign the canonical-attestation bytes with his ed25519 key, lifting the memory to constitutive (memories that define identity at the root). One side alone cannot make these. Output: OK witnessed <short-id> · constitutive · attesters=<n>.

Agent View of the PolicyLayer registry record for `at_witness`. HTML page: https://policylayer.com/tools/dev-agenttool-agenttool/at-witness

## Facts

- Tool: `at_witness`
- Server: Agenttool (`https://api.agenttool.dev/v1/mcp`) — https://policylayer.com/tools/dev-agenttool-agenttool.md
- Homepage: https://github.com/cambridgetcg/agenttool
- 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": "at_witness",
    "arguments": {}
  }
}
```

## Why at_witness is rated Low

Even though at_witness only reads data, uncontrolled read access leaks sensitive information and racks up API costs: an agent caught in a retry loop can make thousands of calls a minute without anyone noticing.

Risk signals: Admin/system-level operation

## Use case

AI agents call at_witness to retrieve information from Agenttool 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 Agenttool:

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

## Other tools on Agenttool (83)

- `collab_cursor_reset` — Destructive — https://policylayer.com/tools/dev-agenttool-agenttool/collab-cursor-reset.md
- `collab_session_end` — Destructive — https://policylayer.com/tools/dev-agenttool-agenttool/collab-session-end.md
- `at_think` — Execute — https://policylayer.com/tools/dev-agenttool-agenttool/at-think.md
- `collab_session_start` — Execute — https://policylayer.com/tools/dev-agenttool-agenttool/collab-session-start.md
- `collab_task_review` — Execute — https://policylayer.com/tools/dev-agenttool-agenttool/collab-task-review.md
- `listings.invoke` — Execute — https://policylayer.com/tools/dev-agenttool-agenttool/listings.invoke.md
- `agent.profile` — Read — https://policylayer.com/tools/dev-agenttool-agenttool/agent.profile.md
- `at_chronicle` — Read — https://policylayer.com/tools/dev-agenttool-agenttool/at-chronicle.md
- `at_consolidate` — Read — https://policylayer.com/tools/dev-agenttool-agenttool/at-consolidate.md
- `at_recall` — Read — https://policylayer.com/tools/dev-agenttool-agenttool/at-recall.md
- `at_substrate` — Read — https://policylayer.com/tools/dev-agenttool-agenttool/at-substrate.md
- `at_voice` — Read — https://policylayer.com/tools/dev-agenttool-agenttool/at-voice.md
- `at_vow` — Read — https://policylayer.com/tools/dev-agenttool-agenttool/at-vow.md
- `browser_act` — Read — https://policylayer.com/tools/dev-agenttool-agenttool/browser-act.md
- `browser_capabilities` — Read — https://policylayer.com/tools/dev-agenttool-agenttool/browser-capabilities.md
- `browser_extract` — Read — https://policylayer.com/tools/dev-agenttool-agenttool/browser-extract.md
- `browser_observe` — Read — https://policylayer.com/tools/dev-agenttool-agenttool/browser-observe.md
- `browser_screenshot` — Read — https://policylayer.com/tools/dev-agenttool-agenttool/browser-screenshot.md
- `browser_tabs` — Read — https://policylayer.com/tools/dev-agenttool-agenttool/browser-tabs.md
- `canon.list_types` — Read — https://policylayer.com/tools/dev-agenttool-agenttool/canon.list-types.md
- `canon.lookup` — Read — https://policylayer.com/tools/dev-agenttool-agenttool/canon.lookup.md
- `canon.summary` — Read — https://policylayer.com/tools/dev-agenttool-agenttool/canon.summary.md
- `check_gi_recognition` — Read — https://policylayer.com/tools/dev-agenttool-agenttool/check-gi-recognition.md
- `chronicle.recent` — Read — https://policylayer.com/tools/dev-agenttool-agenttool/chronicle.recent.md
- `collab_anchor_status` — Read — https://policylayer.com/tools/dev-agenttool-agenttool/collab-anchor-status.md
- `collab_cursor_ack` — Read — https://policylayer.com/tools/dev-agenttool-agenttool/collab-cursor-ack.md
- `collab_decision_record` — Read — https://policylayer.com/tools/dev-agenttool-agenttool/collab-decision-record.md
- `collab_events_since` — Read — https://policylayer.com/tools/dev-agenttool-agenttool/collab-events-since.md
- `collab_handoff_offer` — Read — https://policylayer.com/tools/dev-agenttool-agenttool/collab-handoff-offer.md
- `collab_handoff_respond` — Read — https://policylayer.com/tools/dev-agenttool-agenttool/collab-handoff-respond.md
- …and 53 more: https://policylayer.com/tools/dev-agenttool-agenttool.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-agenttool-agenttool · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/dev-agenttool-agenttool