Filter a JSON object or array to include only specified fields. Useful for reducing REST response payloads to match GraphQL selection sets.
Part of the Graphql Rest Bridge server.
Free to start. No card required.
AI agents call field_optimizer to retrieve information from Graphql Rest Bridge 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 field_optimizer 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.
{
"version": "1",
"default": "deny",
"tools": {
"field_optimizer": {}
}
}See the full Graphql Rest Bridge policy for all 4 tools.
These attack patterns abuse exactly the kind of access field_optimizer gives an agent. Each links to the full case and the policy that stops it:
Other read tools across the catalogue. The same approach applies to each: allow, with a rate cap to control cost.
Filter a JSON object or array to include only specified fields. Useful for reducing REST response payloads to match GraphQL selection sets.. It is categorised as a Read tool in the Graphql Rest Bridge MCP Server, which means it retrieves data without modifying state.
Register the Graphql Rest Bridge MCP server in PolicyLayer and add a rule for field_optimizer: 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 Graphql Rest Bridge. Nothing to install.
field_optimizer 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 field_optimizer 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 field_optimizer. 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.
field_optimizer is provided by the Graphql Rest Bridge MCP server (https://api.lazy-mac.com/graphql-rest-bridge/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 4 Graphql Rest Bridge tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
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