Extract structured JSON data from a URL using Claude AI and a provided JSON schema.
Risk signalsAccepts URL/endpoint input (url)
Part of the SparkForge server.
Free to start. No card required.
AI agents call extract_structured to retrieve information from SparkForge 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 extract_structured 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": {
"extract_structured": {}
}
}See the full SparkForge policy for all 33 tools.
These attack patterns abuse exactly the kind of access extract_structured 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.
Extract structured JSON data from a URL using Claude AI and a provided JSON schema.. It is categorised as a Read tool in the SparkForge MCP Server, which means it retrieves data without modifying state.
Register the SparkForge MCP server in PolicyLayer and add a rule for extract_structured: 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 SparkForge. Nothing to install.
extract_structured 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 extract_structured 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 extract_structured. 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.
extract_structured is provided by the SparkForge MCP server (henry-ships/sparkforge). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 33 SparkForge tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
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