MCP Intelligence

Know every MCP.
Trust the right ones.

A live index of implementation identity, distribution, adoption, and exact-version security evidence.

Intelligence online71,584 source records normalized

Known implementations71,565Deduplicated catalog npm ecosystem16,865Primary npm distributions PyPI ecosystem5,411Primary Python distributions Remote MCPs5,032Linked remote implementations Risk conditions508Current versions with proven risk evidence

Search across names, publishers, packages, repositories, and identifiers.

Live filters

1,601 implementations · ranked by adoption

1 / 17

Implementation indexIdentity · distribution · evidence · adoption

MCP implementation

World Monitor MCP

koala73

Distribution

pypiworldmonitor-sdk

Current version 0.1.1

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal81,164

Ecosystem leader · GitHub stars

Investigate

MCP implementation

Context7 MCP

upstash

Distribution

npm@upstash/context7-mcp

Current version 4.0.5

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal60,654

Ecosystem leader · GitHub stars

Investigate

MCP implementation

ishika_mcp

crewAIInc

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal57,867

Ecosystem leader · GitHub stars

Investigate

MCP implementation

firecrawl-mcp-server

firecrawl

Distribution

npmfirecrawl-mcp

Current version 3.23.9

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal7,207

Established · GitHub stars

Investigate

MCP implementation

Draw.io MCP Server

jgraph

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal5,312

Established · GitHub stars

Investigate

MCP implementation

Exa MCP Server

exa-labs

Distribution

npmexa-mcp-server

Current version 3.4.0

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal4,851

Established · GitHub stars

Investigate

MCP implementation

mcp-server-cloudflare

cloudflare

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal4,060

Established · GitHub stars

Investigate

MCP implementation

mcp-server-browserbase

browserbase

Distribution

npm@browserbasehq/mcp

Current version 3.0.0

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal3,413

Established · GitHub stars

Investigate

MCP implementation

ShipSwift

signerlabs

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal2,981

Established · GitHub stars

Investigate

MCP implementation

korean-law-mcp

chrisryugj

Distribution

npmkorean-law-mcp

Current version 4.12.2

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal2,443

Established · GitHub stars

Investigate

MCP implementation

Microsoft Learn Docs MCP Server

MicrosoftDocs

Distribution

source_gitmicrosoftdocs/mcp

Current version caa3d670bf2814171dba4f7346ece5080964021e

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal1,866

Established · GitHub stars

Investigate

MCP implementation

AnySearch

anysearch-ai

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal1,839

Established · GitHub stars

Investigate

MCP implementation

MeiGen AI Image Generation MCP

jau123

Distribution

npmmeigen

Current version 1.4.0

Intelligence coverageVerified clean

Proof updated Aug 16, 2026

Adoption signal1,670

Established · GitHub stars

Investigate

MCP implementation

datagouv-mcp

datagouv

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal1,589

Established · GitHub stars

Investigate

MCP implementation

emailmd

anypost

Distribution

source_gitanypost/emailmd

Current version b6780794714b1801e05d62528b0dde7dee9a5b2f

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal1,337

Established · GitHub stars

Investigate

MCP implementation

MCPJungle mcp gateway

mcpjungle

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal1,240

Established · GitHub stars

Investigate

MCP implementation

Solana MCP by Vybe

vybenetwork

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal1,226

Established · GitHub stars

Investigate

MCP implementation

Yargı MCP

saidsurucu

Distribution

pypiyargi-mcp

Current version 0.2.2

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal1,094

Established · GitHub stars

Investigate

MCP implementation

OpenAPI

janwilmake

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal900

Emerging · GitHub stars

Investigate

MCP implementation

TickDB MCP

TickDB

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal739

Emerging · GitHub stars

Investigate

MCP implementation

sosumi.ai

NSHipster

Distribution

npm@nshipster/sosumi

Current version 1.0.8

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal458

Emerging · GitHub stars

Investigate

MCP implementation

mu

micro

Distribution

github_releasemicro/mu

Current version v1.6.2+sha256.675bab6f2dc3

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal423

Emerging · GitHub stars

Investigate

MCP implementation

taibu

hhszzzz

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal418

Emerging · GitHub stars

Investigate

MCP implementation

MisakaNet

Ikalus1988

Distribution

pypimisakanet

Current version 2.18.0

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal393

Emerging · GitHub stars

Investigate

MCP implementation

PageIndex MCP

VectifyAI

Distribution

npm@pageindex/mcp

Current version 1.8.2

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal378

Emerging · GitHub stars

Investigate

MCP implementation

OpenAccountants

openaccountants

Distribution

pypiopenaccountants-mcp

Current version 0.1.1

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal320

Emerging · GitHub stars

Investigate

MCP implementation

Hugging Face MCP Server

huggingface

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal288

Emerging · GitHub stars

Investigate

MCP implementation

squirrelscan

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal265

Emerging · GitHub stars

Investigate

MCP implementation

Mevzuat MCP

saidsurucu

Distribution

pypimevzuat-mcp

Current version 0.3.0

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal227

Emerging · GitHub stars

Investigate

MCP implementation

mcp-victoriametrics

VictoriaMetrics

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal225

Emerging · GitHub stars

Investigate

MCP implementation

SAP Documentation MCP Server

marianfoo

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal217

Emerging · GitHub stars

Investigate

MCP implementation

Design Systems MCP Server

southleft

Distribution

npmdesign-systems-mcp

Current version 1.0.0

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal197

Emerging · GitHub stars

Investigate

MCP implementation

Equibles

daniel3303

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal195

Emerging · GitHub stars

Investigate

MCP implementation

livetennisapi-mcp

livetennisapi

Distribution

npmlivetennisapi-mcp

Current version 1.4.0

Intelligence coverageVerified clean

Proof updated Aug 16, 2026

Adoption signal190

Emerging · GitHub stars

Investigate

MCP implementation

SerpApi MCP Server

serpapi

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal167

Emerging · GitHub stars

Investigate

MCP implementation

svelte-llm

khromov

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal160

Emerging · GitHub stars

Investigate

MCP implementation

TWSE MCP Server

twjackysu

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal159

Emerging · GitHub stars

Investigate

MCP implementation

PayRam MCP Server

PayRam

Distribution

source_gitpayram/payram-mcp

Current version 3d9abc6b301b0dbd2ac290de69dc50a557ff0a18

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal155

Emerging · GitHub stars

Investigate

MCP implementation

Financial Modeling Prep MCP Server

imbenrabi

Distribution

npmfinancial-modeling-prep-mcp-server

Current version 2.6.12

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal140

Emerging · GitHub stars

Investigate

MCP implementation

Socket MCP Server

SocketDev

Distribution

npm@socketsecurity/mcp

Current version 0.0.20

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal126

Emerging · GitHub stars

Investigate

MCP implementation

YokTez MCP

saidsurucu

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal125

Emerging · GitHub stars

Investigate

MCP implementation

RivalSearchMCP

damionrashford

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal119

Emerging · GitHub stars

Investigate

MCP implementation

Apple RAG MCP

BingoWon

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal115

Emerging · GitHub stars

Investigate

MCP implementation

REMnux MCP Server

REMnux

Distribution

npm@remnux/mcp-server

Current version 0.1.72

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal113

Emerging · GitHub stars

Investigate

MCP implementation

GoSQLX

ajitpratap0

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal110

Emerging · GitHub stars

Investigate

MCP implementation

Analook

Gingiris-1031

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal108

Emerging · GitHub stars

Investigate

MCP implementation

OpenTofu MCP Server

opentofu

Distribution

npm@opentofu/opentofu-mcp-server

Current version 0.1.5

Intelligence coverageVerified clean

Proof updated Aug 15, 2026

Adoption signal106

Emerging · GitHub stars

Investigate

MCP implementation

gmp-code-assist

googlemaps

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal105

Emerging · GitHub stars

Investigate

MCP implementation

PCB Parts MCP Server

Averyy

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal104

Emerging · GitHub stars

Investigate

MCP implementation

OP.GG MCP Server

opgginc

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal102

Emerging · GitHub stars

Investigate

MCP implementation

İhale MCP

saidsurucu

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal97

Emerging · GitHub stars

Investigate

MCP implementation

mcp-victorialogs

VictoriaMetrics

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal94

Emerging · GitHub stars

Investigate

MCP implementation

abap-mcp-server

marianfoo

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal88

Emerging · GitHub stars

Investigate

MCP implementation

Scira AI MCP Server

zaidmukaddam

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal83

Emerging · GitHub stars

Investigate

MCP implementation

RimSage

realloon

Distribution

npmrimsage

Current version 1.0.1

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal80

Emerging · GitHub stars

Investigate

MCP implementation

quran-mcp

quran

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal77

Emerging · GitHub stars

Investigate

MCP implementation

ai-news-mcp

treesoop

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal70

Emerging · GitHub stars

Investigate

MCP implementation

YOKATLAS API MCP Server

saidsurucu

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal70

Emerging · GitHub stars

Investigate

MCP implementation

pubmed-mcp-server

AIAnytime

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal67

Emerging · GitHub stars

Investigate

MCP implementation

Astro Docs MCP Server

withastro

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal66

Emerging · GitHub stars

Investigate

MCP implementation

Lex

i-dot-ai

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal65

Emerging · GitHub stars

Investigate

MCP implementation

ArchHub MCP

chrisryugj

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal64

Emerging · GitHub stars

Investigate

MCP implementation

whois

KincaidYang

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal63

Emerging · GitHub stars

Investigate

MCP implementation

Gitee

oschina

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal61

Emerging · GitHub stars

Investigate

MCP implementation

Epicure MCP Server

KAIKAKU-AI

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal59

Emerging · GitHub stars

Investigate

MCP implementation

shadcn-svelte-mcp

Michael-Obele

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal58

Emerging · GitHub stars

Investigate

MCP implementation

Enkrypt AI Secure MCP Gateway

enkryptai

Distribution

pypisecure-mcp-gateway

Current version 2.2.3

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal57

Emerging · GitHub stars

Investigate

MCP implementation

Gread

NitroRCr

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal57

Emerging · GitHub stars

Investigate

MCP implementation

KDAN PDF

KDAN-PDF

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal57

Emerging · GitHub stars

Investigate

MCP implementation

mcp-fractera

Fractera

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal56

Emerging · GitHub stars

Investigate

MCP implementation

Zerion Hosted MCP

zeriontech

Distribution

npmzerion-cli

Current version 1.9.1

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal55

Emerging · GitHub stars

Investigate

MCP implementation

Swiss Case Law Open Dataset MCP

jonashertner

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal54

Emerging · GitHub stars

Investigate

MCP implementation

Korean Patent MCP (KIPRIS)

chrisryugj

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal52

Emerging · GitHub stars

Investigate

MCP implementation

MIDI MCP Server

tubone24

Distribution

source_gittubone24/midi-mcp-server

Current version fdde5a98b5adb0efc2beffceff9485f089a08f34

Intelligence coverageVerified clean

Proof updated Aug 25, 2026

Adoption signal51

Emerging · GitHub stars

Investigate

MCP implementation

CometChat Docs

cometchat

Distribution

source_gitcometchat/docs-mcp

Current version 08720fc76ec86abf57790c877b36b4751af35572

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal49

Emerging · GitHub stars

Investigate

MCP implementation

Mintlify Index

mintlify

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal49

Emerging · GitHub stars

Investigate

MCP implementation

Fast MCP Telegram

leshchenko1979

Distribution

pypifast-mcp-telegram

Current version 0.44.2

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal48

Emerging · GitHub stars

Investigate

MCP implementation

Local MCP

lanchuske

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal46

Emerging · GitHub stars

Investigate

MCP implementation

open-agreements

Distribution

npmopen-agreements

Current version 0.10.0

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal46

Emerging · GitHub stars

Investigate

MCP implementation

Blockscout MCP Server

blockscout

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal44

Emerging · GitHub stars

Investigate

MCP implementation

Marka Patent MCP

saidsurucu

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal44

Emerging · GitHub stars

Investigate

MCP implementation

BuiltWith MCP

builtwith

Distribution

npm@builtwith/mcp-server

Current version 1.8.0

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal42

Emerging · GitHub stars

Investigate

MCP implementation

DexPaprika (CoinPaprika)

coinpaprika

Distribution

npmdexpaprika-mcp

Current version 2.5.0

Intelligence coverageVerified clean

Proof updated Aug 16, 2026

Adoption signal42

Emerging · GitHub stars

Investigate

MCP implementation

Remotion MCP App

mcp-use

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal42

Emerging · GitHub stars

Investigate

MCP implementation

Vaaya

vaaya-ai

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal41

Emerging · GitHub stars

Investigate

MCP implementation

Literatür MCP

saidsurucu

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal39

Emerging · GitHub stars

Investigate

MCP implementation

PixelLab

pixellab-code

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal38

Emerging · GitHub stars

Investigate

MCP implementation

Open Targets Platform MCP

opentargets

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal37

Emerging · GitHub stars

Investigate

MCP implementation

youtube-transcript-mcp

ergut

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal37

Emerging · GitHub stars

Investigate

MCP implementation

Bilig WorkPaper

proompteng

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal35

Emerging · GitHub stars

Investigate

MCP implementation

Lenny's Podcast MCP

akshayvkt

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal35

Emerging · GitHub stars

Investigate

MCP implementation

prompts.chat MCP Server

Distribution

npm@fkadev/prompts.chat-mcp

Current version 1.0.9

Intelligence coverageVerified clean

Proof updated Aug 15, 2026

Adoption signal33

Emerging · GitHub stars

Investigate

MCP implementation

contrastapi

UPinar

Distribution

pypicontrastapi

Current version 1.24.0

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal32

Emerging · GitHub stars

Investigate

MCP implementation

deBridge

debridge-finance

Distribution

npm@debridge-finance/debridge-mcp

Current version 0.1.5

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal32

Emerging · GitHub stars

Investigate

MCP implementation

Infobip

infobip

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal32

Emerging · GitHub stars

Investigate

MCP implementation

Flow Studio - Power Automate MCP Server

ninihen1

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal31

Emerging · GitHub stars

Investigate

MCP implementation

Klever MCP Server

klever-io

Distribution

npm@klever/mcp-server

Current version 1.3.0

Intelligence coverageVerified clean

Proof updated Aug 15, 2026

Adoption signal31

Emerging · GitHub stars

Investigate

MCP implementation

Lotus Wisdom MCP Server

linxule

Distribution

npmlotus-wisdom-mcp

Current version 0.8.0

Intelligence coverageVerified clean

Proof updated Aug 19, 2026

Adoption signal31

Emerging · GitHub stars

Investigate

MCP implementation

HealthClawGuardrails

aks129

Distribution

sourceNo package linked

Current version Unresolved

Intelligence coverageCatalog profile

Identity and distribution mapped

Adoption signal29

Emerging · GitHub stars

Investigate

100

MCP implementation

Agent Room

agent-room-alkl

Distribution

npmagent-room

Current version 0.2.5

Intelligence coverageRisk condition detected

Proof updated Aug 20, 2026

Adoption signal28

Emerging · GitHub stars

Investigate