AI agents call list_json_schema_versions to retrieve information from Synapse without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and enumerates existing JSON Schema versions without modifying, executing, or deleting any data. The use of 'list' and pagination indicates a query operation that returns information about schema versions. No side effects or state changes occur. This is a straightforward read operation with minimal blast radius if misused by an agent.
From the tool's definition Tool name contains 'list' and description states 'List versions of a JSON Schema' with token-based pagination support. The action is read-only retrieval of schema version metadata.
Attacks that exploit this kind of access
List versions of a JSON Schema (token-paginated). It is categorised as a Read tool in the Synapse MCP Server, which means it retrieves data without modifying state.
Register the Synapse MCP server in PolicyLayer and add a rule for list_json_schema_versions: 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 Synapse. Nothing to install.
list_json_schema_versions 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 list_json_schema_versions 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 list_json_schema_versions. 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.
list_json_schema_versions is provided by the Synapse MCP server (sage-bionetworks/synapse-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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