double_factorial
The double factorial n!!. Even n uses the even factors down to 2, and odd n uses the odd factors down to 1. 0!! is 1, 6!! is 48, and 7!! is 105. n runs from 0 to 4096. Past 15 digits the value is a decimal string. Price: $0.001 USDC per successful call (x402, Solana). Same tool over HTTPS: POST h...
This record as markdown: /tools/com-it-scorptech-x402/double-factorial.md
What double_factorial does on ScorpTech x402 API
AI agents call double_factorial to retrieve information from ScorpTech x402 API without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
| Parameter | Type | Required | Description |
|---|---|---|---|
n | integer | Yes |
Parameters from the server's own tool schema.
Why double_factorial is rated Low
Even though double_factorial only reads data, uncontrolled read access leaks sensitive information and racks up API costs: an agent caught in a retry loop can make thousands of calls a minute without anyone noticing.
Attacks that exploit this kind of access
The rule that runs double_factorial safely
PolicyLayer is an MCP gateway: it sits between your AI agents and ScorpTech x402 API, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For double_factorial, this is the rule to start with:
double_factorial is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect ScorpTech x402 API, apply this rule, and every double_factorial call is checked against it from then on.
Questions about double_factorial
The double factorial n!!. Even n uses the even factors down to 2, and odd n uses the odd factors down to 1. 0!! is 1, 6!! is 48, and 7!! is 105. n runs from 0 to 4096. Past 15 digits the value is a decimal string. Price: $0.001 USDC per successful call (x402, Solana). Same tool over HTTPS: POST https://scorptech.it.com/api/x402/v1/double-factorial. It is categorised as a Read tool in the ScorpTech x402 API MCP Server, which means it retrieves data without modifying state.
double_factorial accepts 1 parameter: n. Required: n. The full parameter table on this page comes from the server's own tool schema.
Register the ScorpTech x402 API MCP server in PolicyLayer and add a rule for double_factorial: 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 ScorpTech x402 API. Nothing to install.
double_factorial 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 double_factorial 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 double_factorial. 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.
double_factorial is provided by the ScorpTech x402 API MCP server (https://scorptech.it.com/api/x402/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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