mcp-guard
NPM · MCP-GUARD-SCAN
Security scanner for MCP servers: tool poisoning, shadowing, permissions, secrets, transport.
Available components
Last scanned (9 hours ago)
Scores higher than 69% of npm servers
Category Security
How this component scores in each security and reliability category. Every signal is checked automatically from public evidence about the published package, including repeated runs of it in an isolated sandbox, and we only credit what we can confirm. How we score → Why this is hard to score →
Supply Chain Security98
- No malware found by supply-chain analysis.Pass
- No known CVEs affecting this package version or its production dependencies.Pass
- No install/post-install scripts declared.Pass
- 34 of 106 dependencies flagged as unhealthy. View diagnostics → Partial
Provenance & Transparency97
- Source repository is publicly reachable at the declared URL. View diagnostics → Pass
- Cryptographically verified build provenance (signed, bound to diegoperezg7/mcp-guard-scan). View diagnostics → Pass
- Clear OSI-approved license (Apache-2.0).Pass
- Actively maintained (last published 0 days ago).Pass
- Disclosure check failed: no security disclosure policy was found in the source repository. See how to fix → Fail
Schema Quality & AI Usability77
- AI-judged instruction clarity (excellent).Pass
- Context-footprint check failed: tool/resource definitions use about 516 tokens (~129/item across 4 items; 4 tools + 0 resources), over budget; trim descriptions and params. See how to fix → Fail
- Usage-examples check failed: none of the tools include examples. See how to fix → Fail
Stability & Change Management3
- Stability observed for 1 of 30 days with no destabilising changes; credit accrues until the full window elapses.Partial
Tool Coverage100
- 100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
- 100% of tool parameters carry a description.Pass
- Structured output schemas are declared (75% of tools); any adoption earns full credit.Pass
Tool Safety100
- No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.Pass
- We read all 4 captured tool definition(s), and no name or description among them implies an irreversible operation.Pass
- An AI judge read all 5 captured unit(s) of tool text and found none that tries to manipulate the model reading it.Pass
Capabilities100
- Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.Pass
Every change we have recorded for this component, newest first. Security-relevant changes are always shown. ▲ marks a change for the better, ▼ a change for the worse; unmarked changes are neutral.
- 5 Nov 26 +11
- Known CVEs: unverified → pass ▲ security
- Dependency health: unverified → 0.86 ▲ functional
- 4 Nov 26 70
First indexed and scored.
Diagnostic detail from the automated scan of this channel: what the scanner observed at each step, so you can see exactly where a check passed or failed. It is informational only and never changes the trust score.
Captured 5 Nov 2026 · Analysed npm/mcp-guard-scan@1.1.1
Provenance Verified
A signed build attestation was found and verified, binding this exact artifact to the source repository it claims to come from.
| Result | Verified |
|---|---|
| Ecosystem | npm |
| Reason | Verified |
| Discovered via | Registry attestation endpoint |
| Source repo | diegoperezg7/mcp-guard-scan |
| Certificate issuer | https://token.actions.githubusercontent.com |
| Certificate SAN | https://github.com/diegoperezg7/mcp-guard-scan/.github/workflows/release.yml@refs/tags/v1.1.1 |
| Rekor log index | 3689008688 |
| Predicate type | SLSA build provenance https://slsa.dev/provenance/v1 |
| Subject digest | sha512:c40c73e7aefe354490b562079fc1a331f26d144a7613b76d5078c822395d5cdff0bc344005d01ff9d04c41421ee613060f5e1a94906180c7e6e2b6125 |
Background: How many MCP packages publish verified provenance →
Dependencies 106 packages
| Packages resolved | 106 |
|---|---|
| Stale | 34 |
| Tree resolution | Complete |
Background: SBOMs and build attestations, explained →
The tools this component advertises to a client, with an estimated token cost for each. Expand a tool to see its parameters and schema. The per-tool counts are indicative and are not scored directly; the schema's total context footprint is one signal in Schema Quality & AI Usability. A tool's description is untrusted text the model reads on every call, which is what makes this list a security surface and not just an inventory: how tool poisoning works →
explain_rule Explain an mcp-guard rule ~55
Explain one rule, e.g. MCPG-002: what it detects, a bad and a good example, how to fix it and references.
| Name | Type | Req | Description |
|---|---|---|---|
| id | string | yes | Rule id, e.g. MCPG-002. |
No output schema declared.
No examples provided.
list_rules List mcp-guard rules ~33
List every MCPG rule with its category, default severity and whether it is static or needs the CLI's --probe mode.
Input schema present but exposes no named parameters.
| Name | Type | Req | Description |
|---|---|---|---|
| rules | array | yes | – |
No examples provided.
scan_server Scan a live MCP server ~137
Connect to a Streamable HTTP MCP endpoint, list its tools, resources and prompts, run every static rule and check the transport (TLS, auth, CORS, session handling). The scanned server's tools are never called. Only public https endpoints; local and private addresses are refused unless the server runs with MCP_GUARD_ALLOW_PRIVATE_NETWORK=1.
| Name | Type | Req | Description |
|---|---|---|---|
| fail_on | string | – | passed is false when a finding is at or above this severity. |
| headers | object | – | HTTP headers for the endpoint, e.g. Authorization. |
| url | string | yes | Streamable HTTP endpoint, e.g. https://example.com/mcp. |
| Name | Type | Req | Description |
|---|---|---|---|
| findings | array | yes | – |
| passed | boolean | yes | False when a finding reaches fail_on. |
| servers | array | yes | – |
| summary | object | yes | Findings per severity. |
No examples provided.
scan_tools_export Scan a tools/list export ~129
Run every static mcp-guard rule over a tools/list result you already have: { "tools": [...] }, a bare array of tools, or { "servers": [{ "name", "tools" }] } to also check shadowing between servers. Nothing is started or contacted. Returns a Markdown report and the findings.
| Name | Type | Req | Description |
|---|---|---|---|
| export | – | yes | The tools/list result, or several servers under a servers key. |
| fail_on | string | – | passed is false when a finding is at or above this severity. |
| name | string | – | Server name used in the report when the export has none. |
| Name | Type | Req | Description |
|---|---|---|---|
| findings | array | yes | – |
| passed | boolean | yes | False when a finding reaches fail_on. |
| servers | array | yes | – |
| summary | object | yes | Findings per severity. |
No examples provided.
How do I install the mcp-guard server?
mcp-guard runs locally as an npm package, launched with npx -y mcp-guard-scan. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.
npm · mcp-guard-scan
claude mcp add diegoperezg7-mcp-guard-scan -- npx -y mcp-guard-scan
What is the mcp-guard server?
mcp-guard is listed in the public MCP registry as io.github.diegoperezg7/mcp-guard-scan. Security scanner for MCP servers: tool poisoning, shadowing, permissions, secrets, transport. This page covers its npm package (mcp-guard-scan).
Is the mcp-guard server safe to use?
mcp-guard scores 81 out of 100 on VerifyMCP. We found no known CVEs affecting it as of 5 November 2026. It declares no install or post-install scripts. Its build provenance is signed and verified. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.
What tools does the mcp-guard server expose?
mcp-guard exposes 4 tools: scan_tools_export, scan_server, list_rules, explain_rule. Their descriptions and schemas cost roughly 354 tokens of context every time the server is loaded.
Is the mcp-guard server still maintained?
mcp-guard is still listed as active in the MCP registry. We last reached this channel on 5 November 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.
What licence is the mcp-guard server under?
mcp-guard declares the Apache-2.0 licence, which is OSI-approved. That covers the source only, and says nothing about the cost of any service it calls.