diff

Returns file-level diff statistics as structured data. Use full=true for patch content.

SERVERNpm SOURCEDave-London/Pare

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-dave-london-npm/diff.md

WHAT IT DOES

What diff does on Npm

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

RISK

Why diff is rated Low

The diff tool only retrieves and returns differential information between files. Even with full=true to include patch content, it remains a read-only operation that queries data without causing side effects, modifications, or execution of commands. No data is created, modified, deleted, or executed by this tool.

From the tool's definition Tool description states it 'Returns file-level diff statistics as structured data' with optional 'patch content'. This is a retrieval operation with no modification, deletion, or execution of code.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs diff safely

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

diff Allowed

diff 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": {
    "diff": {}
  }
}

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

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

FAQ

Questions about diff

What does the diff tool do? +

Returns file-level diff statistics as structured data. Use full=true for patch content. It is categorised as a Read tool in the Npm MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on diff? +

Register the Npm MCP server in PolicyLayer and add a rule for diff: 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 Npm. Nothing to install.

What risk level is diff? +

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

Can I rate-limit diff? +

Yes. Add a rate_limit block to the diff 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 diff completely? +

Set action: deny in the PolicyLayer policy for diff. 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 diff? +

diff is provided by the Npm MCP server (Dave-London/Pare). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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