AI agents call schema_observe to retrieve information from Zion without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
| Parameter | Type | Required | Description |
|---|---|---|---|
op | string | Yes | |
limit | number | — | |
projectExId | string | — | |
afterEventId | string | null | — |
Parameters from the server's own tool schema.
This tool retrieves schema metadata and historical change events without modifying data or triggering side effects. The operations are purely informational queries into the daemon's state, making it a Read category tool with low severity since misuse would only expose schema information without enabling destructive or financial harm.
From the tool's definition Tool description explicitly states 'Read the daemon's schema change-state' and provides read-only operations: STATE (retrieves revision, stale flag, latest change event) and EVENTS (retrieves recent semantic schema-change events).
Attacks that exploit this kind of access
Read the daemon's schema change-state for a project. op: STATE (revision, stale flag, latest change event) | EVENTS (recent semantic schema-change events; afterEventId/limit paginate). It is categorised as a Read tool in the Zion MCP Server, which means it retrieves data without modifying state.
schema_observe accepts 4 parameters: op, limit, projectExId, afterEventId. Required: op. The full parameter table on this page comes from the server's own tool schema.
Register the Zion MCP server in PolicyLayer and add a rule for schema_observe: 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 Zion. Nothing to install.
schema_observe is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the schema_observe 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 schema_observe. 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.
schema_observe is provided by the Zion MCP server (zion-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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