Validate JSON data from another agent against expected schema. Essential for preventing malformed data propagation in multi-agent workflows. Returns validation status, errors, and confidence score.
Part of the Agent Output Guard MCP server. Enforce policies on this tool with Intercept, the open-source MCP proxy.
AI agents call verify_json_schema to retrieve information from Agent Output Guard without modifying any data. This is common in research, monitoring, and reporting workflows where the agent needs context before taking action. Because read operations don't change state, they are generally safe to allow without restrictions -- but you may still want rate limits to control API costs.
Even though verify_json_schema only reads data, uncontrolled read access can leak sensitive information or rack up API costs. An agent caught in a retry loop could make thousands of calls per minute. A rate limit gives you a safety net without blocking legitimate use.
Read-only tools are safe to allow by default. No rate limit needed unless you want to control costs.
tools:
verify_json_schema:
rules:
- action: allowSee the full Agent Output Guard policy for all 5 tools.
Agents calling read-class tools like verify_json_schema have been implicated in these attack patterns. Read the full case and prevention policy for each:
Other tools in the Read risk category across the catalogue. The same policy patterns (rate-limit, allow) apply to each.
Validate JSON data from another agent against expected schema. Essential for preventing malformed data propagation in multi-agent workflows. Returns validation status, errors, and confidence score.. It is categorised as a Read tool in the Agent Output Guard MCP Server, which means it retrieves data without modifying state.
Add a rule in your Intercept YAML policy under the tools section for verify_json_schema. You can allow, deny, rate-limit, or validate arguments. Then run Intercept as a proxy in front of the Agent Output Guard MCP server.
verify_json_schema 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 verify_json_schema rule in your Intercept 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 Intercept policy for verify_json_schema. 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.
verify_json_schema is provided by the Agent Output Guard MCP server (@agenson-horrowitz/agent-output-guard-mcp). Intercept sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Open source. One binary. Zero dependencies.
npx -y @policylayer/intercept