PolicyLayer/mcp-server-catalogue

PolicyLayer MCP Server Catalogue

A risk-classified catalogue of every Model Context Protocol (MCP) server reachable through the public registries. Each tool exposed by each server is classified into one of six risk categories using a verb-based classifier with input-schema heuristics.

1,787 servers · 25,329 tools · classified May 2026 · refreshed monthly.

The catalogue is the underlying dataset for PolicyLayer's research report, The State of MCP Security — May 2026.

---

Loading the dataset

from datasets import load_dataset

ds = load_dataset("PolicyLayer/mcp-server-catalogue")
servers = ds["servers"]
tools   = ds["tools"]

print(f"{len(servers)} servers, {len(tools)} tools")

# Find every destructive tool exposed by an identity-provider MCP server
ip_slugs = [s["slug"] for s in servers if "identity" in (s["description"] or "").lower()]
destructive = tools.filter(
    lambda t: t["category"] == "Destructive" and t["server_slug"] in ip_slugs
)

---

Schema

servers split

One row per Model Context Protocol server with at least one classified tool.

Field	Type	Description
slug	string	Stable identifier. Use this to join with tools.server_slug.
name	string	Human-readable server name as published by its author.
packages	array of strings	npm or other package identifiers exposing this server.
repo_url	string | null	Source repository URL where available.
description	string | null	Server-author-supplied description.
tool_count	int	Number of tools the server exposes.
categories	array of strings	Distinct risk categories present in this server's tools. Subset of {Read, Write, Execute, Destructive, Financial, Other}.
source	string	Discovery channel: crawler (npm auto-discovery), smithery (Smithery registry), seed (manually-added official), user_scan (community contribution).
confidence	string	Classifier confidence for this server's labels: high, verified, medium, low.
last_scanned_at	string (ISO 8601)	Most recent scan timestamp.
npm_weekly_downloads	int | null	Weekly downloads of the server's npm package as of the snapshot date. Null if the server is not on npm or the registry didn't return data.
npm_latest_version	string | null	Latest published version on npm.
npm_last_published	string (ISO 8601) | null	Timestamp of the latest npm publish.
github_stars	int | null	GitHub stargazer count for the source repository.
github_forks	int | null	GitHub fork count.
github_open_issues	int | null	Currently-open GitHub issues + pull requests.
github_last_commit	string (ISO 8601) | null	pushed_at timestamp on the GitHub repository — proxy for liveness.
github_license	string | null	SPDX licence identifier reported by GitHub (e.g., MIT, Apache-2.0).
github_archived	bool | null	Whether the GitHub repository is archived (read-only).

tools split

One row per tool exposed by a server in the servers split.

Field	Type	Description
server_slug	string	Foreign key to servers.slug.
name	string	Tool name as exposed via tools/list.
description	string | null	Tool-author-supplied description.
category	string	Risk category. One of Read, Write, Execute, Destructive, Financial, Other.
severity	string	Discrete severity bucket: Low, Medium, High, Critical.
confidence	string	Classifier confidence: high, verified, medium, low.
risk_weight	float	Risk weight in [0.0, 1.0]. 0.0 = read-only, 1.0 = destructive financial.
risk_type	string | null	Specific risk type where determinable (e.g., delete, drop, payment).
input_schema	string | null	JSON-encoded tool input schema. May be null if the source provided no schema.

---

Risk categories

Category	Definition	Risk weight typical range
Read	Retrieves data without modification.	0.05–0.15
Write	Creates or modifies data and resources.	0.20–0.45
Execute	Runs code, scripts, or container commands.	0.40–0.70
Destructive	Permanently deletes or revokes resources.	0.55–0.85
Financial	Moves real money: charges, payments, refunds, transfers.	0.65–1.00
Other	Does not fit the above categories.	varies

Classification is verb-based with input-schema heuristics. Methodology details and known failure modes are documented in the research report.

---

Coverage and limitations

• Public registries only. The dataset covers servers reachable through the official Model Context Protocol registry, npm, Smithery, and Glama. Private and self-hosted servers are not represented.
• Lower bound. Some registry-listed servers are unreachable through the scan pipeline (broken installs, dependency failures, or auth-walled launchers) and are excluded. The dataset is therefore a lower bound on the real ecosystem.
• Static snapshot. This release is the May 2026 edition. New monthly versions are released on the 1st of each month.
• Classifier confidence varies. 72.3% of tool classifications are high-confidence and 15.4% are verified. The remaining 12.3% are medium or low confidence and should be treated as advisory rather than authoritative for downstream risk decisions.
• Usage metrics are point-in-time. npm_weekly_downloads reflects the week immediately before the snapshot. github_* fields reflect the GitHub repository state at fetch time. Metrics are null where the server is not on npm, has no GitHub repo, or the upstream API rate-limited the fetch.

---

Citation

If you use this dataset in research or commentary, please cite the research report:

PolicyLayer. (2026). The State of MCP Security — May 2026.
https://policylayer.com/research/state-of-mcp-2026

For the dataset itself:

PolicyLayer. (2026). PolicyLayer MCP Server Catalogue [Data set].
Hugging Face. https://huggingface.co/datasets/PolicyLayer/mcp-server-catalogue

---

Updates

The catalogue is regenerated monthly from PolicyLayer's continuously-updated scan pipeline. Each monthly release is tagged on Hugging Face. Subscribe to the dataset to be notified of new versions.

Edition	Tag	Servers	Tools
May 2026	2026-05	1,787	25,329

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Related

• Research report: The State of MCP Security — May 2026
• Public tool catalogue: policylayer.com/tools — browse classifications by server.
• MCP attack database: policylayer.com/attacks — documented MCP incidents and attack patterns.
• PolicyLayer: policylayer.com — the MCP control plane (gateway, policy engine, audit log) for production agent fleets.

Questions, methodology details, or data requests: research@policylayer.com.

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Licence

This dataset is released under Creative Commons Attribution 4.0 International (CC-BY-4.0).

You are free to use, share, adapt, and redistribute the data, including for commercial purposes, with attribution to PolicyLayer. The classifier output is the work product of PolicyLayer's research team; tool descriptions and server metadata are the work of their respective authors and remain under whatever licence the source projects supply.