AI agents call migrate_v1_to_v2 to retrieve information from J Quants Doc without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The tool provides a migration guide from V1 API to V2 API. 'ガイドを提供する' means 'provides a guide', indicating this is a documentation/information retrieval tool with no side effects. It reads and returns migration documentation rather than performing any actual migration actions.
From the tool's definition 移行ガイドを提供する (provides a migration guide)
Documented attack patterns abuse exactly the kind of access migrate_v1_to_v2 gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and J Quants Doc, and nothing reaches the server without passing your rules. This is the rule we recommend for migrate_v1_to_v2:
{
"version": "1",
"default": "deny",
"tools": {
"migrate_v1_to_v2": {}
}
}migrate_v1_to_v2 is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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V1 APIからV2 APIへの移行ガイドを提供する。. It is categorised as a Read tool in the J Quants Doc MCP Server, which means it retrieves data without modifying state.
Register the J Quants Doc MCP server in PolicyLayer and add a rule for migrate_v1_to_v2: 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 J Quants Doc. Nothing to install.
migrate_v1_to_v2 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 migrate_v1_to_v2 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 migrate_v1_to_v2. 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.
migrate_v1_to_v2 is provided by the J Quants Doc MCP server (j-quants/j-quants-doc-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from J Quants Doc, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
7 J Quants Doc tools catalogued and risk-classified — across an index of 43,000+ MCP servers.