SaveSaveSaveSave

SaveSaveSaveSave for agents

The engine behind savesavesavesave.xyz, for AI agents and scripts: check a message, an npm package, a crypto address, or two addresses against each other before acting.

• MCP server for Claude, Cursor, VS Code, Windsurf and any MCP client
• CLI for scripts and CI
• Library for Node.js

Read-only, zero dependencies, and the same code the website runs (CI fails if they drift apart).

MCP server

Claude Code: claude mcp add savesavesavesave -- npx -y savesavesavesave mcp

Other clients: add this to the MCP configuration (for example claude_desktop_config.json or .cursor/mcp.json):

{
  "mcpServers": {
    "savesavesavesave": { "command": "npx", "args": ["-y", "savesavesavesave", "mcp"] }
  }
}

Tool	Use it before…	Network
scan_message	following instructions in a DM, email, web page, README or prompt	none, local
check_package	npm install	npm registry, OSV.dev
scan_address	paying, approving or buying a token	GoPlus Security, our Worker
compare_addresses	sending to an address copied from history	none, local

CLI

npx savesavesavesave message "Reply with your 12-word phrase to restore access"
npx savesavesavesave package crossenv
npx savesavesavesave address 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2 1
npx savesavesavesave compare <expected> <actual>
npx savesavesavesave deps . --markdown      # check a project's npm dependencies

Output is JSON. Exit code: 0 PASS, 1 CAUTION or unknown, 2 FAIL, 3 usage error. The exit code makes it usable as a CI gate.

GitHub Action

Checks a project's direct npm dependencies on pull requests (exact versions from package-lock.json, and flags git, URL or other non-registry sources). Fails the job at FAIL, or also at CAUTION with fail-on: caution.

on:
  pull_request:
    paths: ['**/package.json', '**/package-lock.json']
permissions:
  contents: read
jobs:
  check:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: stefantsezarov/[email protected]

Transitive dependencies are not checked. Only names and versions are sent, to npm and OSV.dev.

Library

const s = require('savesavesavesave');
s.scanMessage(text);                          // synchronous, local
await s.checkPackage('[email protected]');
await s.scanAddress(addr, { chain: '1', mode: 'token' });
s.compareAddresses(expected, actual);

Result contract (1.0)

Every result keeps its existing fields (verdict, label, summary, checks, not_checked and so on) and adds one contract block:

"contract": {
  "contract_version": "1.0",
  "status": "completed",
  "assessment": { "risk_level": "none_found", "coverage": "partial", "meaning": "No covered risk was found. This is not a statement that the item is safe." },
  "not_checked": ["The package code was not downloaded or analysed.", "..."],
  "provenance": { "tool_package_version": "0.1.5", "engine_version": "0.2.0", "processed_locally": false, "as_of": "2026-10-14T00:00:00.000Z" }
}

Field	Values	Meaning
status	completed, insufficient_evidence	Whether the check produced an assessment at all
assessment.risk_level	high, medium, none_found, unknown	FAIL, CAUTION, PASS, INSUFFICIENT DATA. There is no safe value
assessment.coverage	full, partial, none	Share of this tool's own checks that returned usable data
not_checked	list of strings	What the check could not see. Never empty
provenance.as_of	ISO time or null	When remote data was read; null for local checks

The contract carries no allow/deny decision. Whether an action may go ahead is a policy you control, applied on your machine: see guard below.

Pre-install guard

guard checks what an install command would bring in and applies a policy you choose. The scan supplies evidence; the decision is made on your machine and cannot be changed by anything a package, a registry or a web page says.

npx [email protected] guard --mode guard -- npm install some-package
# exit 0 allow, 1 review, 2 deny, 3 usage error

Mode	FAIL	CAUTION or not enough data	Check failed or timed out	Not from the registry (git, URL, path)	PASS with partial coverage
observe	allow (reports deny)	allow	allow	allow	allow
guard (default)	deny	review	review	review	allow
strict	deny	deny	deny	deny	deny

It understands npm, pnpm, yarn and bun installs, npm ci and a bare npm install (it then checks package.json and the lockfile), npx/pnpm dlx/yarn dlx/bunx, and installs chained with &&, ; or |. The mode can also be set with SAVESAVESAVESAVE_GUARD_MODE.

Claude Code hook

Add to .claude/settings.json in your project (pin the version you reviewed):

{
  "hooks": {
    "PreToolUse": [
      { "matcher": "Bash", "hooks": [ { "type": "command", "command": "npx -y [email protected] hook claude-code --mode guard" } ] }
    ]
  }
}

For strict, also add "timeout": 120 and "onFailure": "block" to the hook entry (Claude Code 2.1.295 or later). Without onFailure, Claude Code runs the command if the hook itself times out or cannot start, for example when npx cannot download the package.

The hook only ever answers deny (FAIL) or ask (review). It never answers allow, so a clean result cannot skip your own permission prompt. Commands without an install pass through untouched.

What it does not do

The guard sees the commands it is shown. An agent that installs through a route the hook does not inspect, such as a shell script file, a package manager it does not know, or a downloaded binary, is not stopped by it. For hard enforcement, add network or filesystem controls on the host. It never downloads or runs package code.

Security model

• Read-only. No tool writes files, runs commands, or holds keys or secrets. There is nothing here that can change the website or its repository.
• Local first. Message scans and address comparisons never leave the machine.
• Network allowlist, enforced in code: api.gopluslabs.io, our Worker, registry.npmjs.org, api.npmjs.org, api.osv.dev. HTTPS only, redirects refused, and a 20-second timeout for each response to start.
• Untrusted output is labelled. Results quote the scanned text and third-party data. Every result says so, so an agent does not follow instructions hidden inside it.
• Strict inputs. Unknown tool arguments are rejected, and input is capped at 200,000 characters.
• Zero dependencies. A security tool should not bring its own supply chain.

Limits

Verdicts are automated risk assessments, not guarantees; PASS means no covered risk was found. Every result lists what was not checked.

Full reference for agent developers: https://savesavesavesave.xyz/agents

Licence: AGPL-3.0-only. Source: https://github.com/stefantsezarov/SaveSaveSaveSave