Add new observations to existing entities in the knowledge graph
AI agents use add_observations to create or update resources in Elasticsearch Knowledge Graph for MCP — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Elasticsearch Knowledge Graph for MCP environment.
This tool creates new observational data within the knowledge graph, modifying the state of entities by appending information. While it modifies data, it is not destructive (data can be removed), not executable (no code/commands), and not financial.
From the tool's definition Tool name 'add_observations' and description 'Add new observations to existing entities in the knowledge graph' indicate creation/modification of data.
Documented attack patterns abuse exactly the kind of access add_observations gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Elasticsearch Knowledge Graph for MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for add_observations:
{
"version": "1",
"default": "deny",
"tools": {
"add_observations": {
"limits": [
{
"counter": "add_observations_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
} add_observations stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
Free to start. No card required.
Add new observations to existing entities in the knowledge graph. It is categorised as a Write tool in the Elasticsearch Knowledge Graph for MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Elasticsearch Knowledge Graph for MCP server in PolicyLayer and add a rule for add_observations: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Elasticsearch Knowledge Graph for MCP. Nothing to install.
add_observations is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the add_observations rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for add_observations. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
add_observations is provided by the Elasticsearch Knowledge Graph for MCP server (j3k0/mcp-brain-tools). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Elasticsearch Knowledge Graph for MCP, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
23 Elasticsearch Knowledge Graph for MCP tools catalogued and risk-classified — across an index of 43,000+ MCP servers.