# delete_observation

Remove specific observation(s) from entity/entities

Agent View of the PolicyLayer registry record for `delete_observation`. HTML page: https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/delete-observation

## Facts

- Tool: `delete_observation`
- Server: Project Guardian MCP (`1999azzar/project-guardian-mcp-server`) — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server.md
- Homepage: https://github.com/1999AZZAR/project-guardian-mcp-server
- Risk category: Destructive (Critical risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 0
- Recommended policy verdict: Hidden

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

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

## Why delete_observation is rated Critical

This tool permanently deletes observations from the knowledge graph database. Deletion is irreversible and cannot be undone through normal operations. While the blast radius is limited to observation records (not entire entities or the full database), the destructive nature and potential to corrupt project memory context in an AI-driven system warrants 'high' severity.

From the tool's own definition: "Tool name is 'delete_observation' with description 'Remove specific observation(s) from entity/entities'. The verb 'Remove' and 'delete' indicate irreversible deletion of data records."

## Use case

AI agents call delete_observation to permanently remove resources in Project Guardian MCP, typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.

## Recommended policy (PolicyLayer)

Verdict: **Hidden**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Project Guardian MCP:

```json
{
  "version": "1",
  "default": "deny",
  "hide": [
    "delete_observation"
  ]
}
```

## Other tools on Project Guardian MCP (37)

- `cache_delete` — Destructive — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/cache-delete.md
- `delete_data` — Destructive — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/delete-data.md
- `delete_entity` — Destructive — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/delete-entity.md
- `delete_relation` — Destructive — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/delete-relation.md
- `close_ui` — Execute — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/close-ui.md
- `execute_sql` — Execute — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/execute-sql.md
- `initialize_memory` — Execute — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/initialize-memory.md
- `scan_container_image` — Execute — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/scan-container-image.md
- `start_ui` — Execute — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/start-ui.md
- `stop_ui` — Execute — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/stop-ui.md
- `analyze_git_changes` — Read — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/analyze-git-changes.md
- `cache_get` — Read — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/cache-get.md
- `cache_scan` — Read — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/cache-scan.md
- `export_data` — Read — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/export-data.md
- `get_file_context` — Read — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/get-file-context.md
- `get_project_guidance` — Read — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/get-project-guidance.md
- `get_session_context` — Read — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/get-session-context.md
- `get_timeline` — Read — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/get-timeline.md
- `inspect_untrusted_text` — Read — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/inspect-untrusted-text.md
- `list_harness_stores` — Read — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/list-harness-stores.md
- `open_node` — Read — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/open-node.md
- `query_data` — Read — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/query-data.md
- `read_graph` — Read — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/read-graph.md
- `read_graph_stream` — Read — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/read-graph-stream.md
- `scan_project_secrets` — Read — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/scan-project-secrets.md
- `search_nodes` — Read — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/search-nodes.md
- `sync_central_memory` — Read — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/sync-central-memory.md
- `add_observation` — Write — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/add-observation.md
- `cache_set` — Write — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/cache-set.md
- `create_entity` — Write — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/create-entity.md
- …and 7 more: https://policylayer.com/tools/1999azzar-project-guardian-mcp-server.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`

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Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=1999azzar-project-guardian-mcp-server · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/1999azzar-project-guardian-mcp-server