ast_transform_preview

Preview lightweight AST-like transforms (string/regex based) and return before/after diff.

SERVERJshookmcp SOURCE@jshookmcp/jshook

Low RISK CLASS

Category Read

Parameters 00 required

Recommended Allowedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/io-github-vmoranv-jshookmcp/ast-transform-preview.md

WHAT IT DOES

What ast_transform_preview does on Jshookmcp

AI agents call ast_transform_preview to retrieve information from Jshookmcp without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

RISK

Why ast_transform_preview is rated Low

Tool only previews transforms and returns a diff without applying changes.

From the tool's definition Preview... return before/after diff

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs ast_transform_preview safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Jshookmcp, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For ast_transform_preview, this is the rule to start with:

ast_transform_preview Allowed

ast_transform_preview is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "ast_transform_preview": {}
  }
}

ALLOW ONLY THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Jshookmcp, apply this rule, and every ast_transform_preview call is checked against it from then on.

FAQ

Questions about ast_transform_preview

What does the ast_transform_preview tool do? +

Preview lightweight AST-like transforms (string/regex based) and return before/after diff. It is categorised as a Read tool in the Jshookmcp MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on ast_transform_preview? +

Register the Jshook MCP server in PolicyLayer and add a rule for ast_transform_preview: 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 Jshookmcp. Nothing to install.

What risk level is ast_transform_preview? +

ast_transform_preview is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit ast_transform_preview? +

Yes. Add a rate_limit block to the ast_transform_preview 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.

How do I block ast_transform_preview completely? +

Set action: deny in the PolicyLayer policy for ast_transform_preview. 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.

What MCP server provides ast_transform_preview? +

ast_transform_preview is provided by the Jshook MCP server (@jshookmcp/jshook). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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