Web Researcher MCP MCP Server

<!-- mcp-name: io.github.zoharbabin/web-researcher-mcp --> <p align="center"> <img src="assets/logo-final.svg" width="120" height="120" alt="web-researcher-mcp logo"> </p> <h1 align="center">web-researcher-mcp</h1> <p align="center"> <strong>Your AI research assistant that cites real sources and stays honest.</strong> </p> <p align="center"> Search the entire web or narrow it down to just the sites you trust;<br/> medical journals, court databases, news outlets, academic papers.<br/> Analyze the full source, not just snippets. Links that work, citations you can trust,<br/> no made up closed garden pre-synthesized results. </p>

⭐ If you're tired of AI making things up, and web-researcher-mcp helps you, give us a star ⭐ — it helps more teams discover the project.

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Get started in 30 seconds

Python users — uvx (no compile, any OS):

# One-time: install uv (skip if you already have it)
curl -LsSf https://astral.sh/uv/install.sh | sh        # macOS/Linux  (Windows: winget install astral-sh.uv)

claude mcp add --scope user web-researcher -- uvx web-researcher-mcp

uv fetches the right prebuilt binary for your platform and runs it — no Go, no compile, no manual PATH. Point any MCP client at uvx web-researcher-mcp. Also works with uv tool install web-researcher-mcp or pip install web-researcher-mcp.

Python SDK

from web_researcher_mcp import WebResearcherClient

async with WebResearcherClient() as client:
    response = await client.web_search("CRISPR off-target effects 2024", num_results=5)
    for r in response.results:
        verified = await client.verify_citation(r.url)
        print(r.title, "—", "✓" if verified.exists else "?")

Full documentation: docs/PYTHON_CLIENT.md

Sync wrapper (for scripts and notebooks that don't use async):

with WebResearcherClient.sync() as client:
    response = client.web_search("climate change 2024")
    print(response.results[0].title)

macOS (Homebrew):

brew install zoharbabin/tap/web-researcher-mcp
claude mcp add --scope user web-researcher -- web-researcher-mcp

macOS / Linux (no package manager):

curl -fsSL https://raw.githubusercontent.com/zoharbabin/web-researcher-mcp/main/install.sh | sh

Windows (PowerShell):

powershell -ExecutionPolicy Bypass -c "irm https://raw.githubusercontent.com/zoharbabin/web-researcher-mcp/main/install.ps1 | iex"

No dev tools needed — every method ships the same signed binary (the PyPI wheels vendor it; the others download it and verify its checksum) and puts it on your PATH. The curl/PowerShell installers also register it with Claude Code automatically when the claude CLI is present; Homebrew installs the binary, so run the claude mcp add line above to connect it.

One-click install:

<p> <a href="https://cursor.com/en/install-mcp?name=web-researcher&config=eyJjb21tYW5kIjoidXZ4IiwiYXJncyI6WyJ3ZWItcmVzZWFyY2hlci1tY3AiXX0%3D"><img src="https://cursor.com/deeplink/mcp-install-dark.svg" alt="Add to Cursor" height="28"></a> <a href="https://vscode.dev/redirect?url=vscode%3Amcp%2Finstall%3F%257B%2522name%2522%253A%2522web-researcher%2522%252C%2522command%2522%253A%2522uvx%2522%252C%2522args%2522%253A%255B%2522web-researcher-mcp%2522%255D%257D"><img src="https://img.shields.io/badge/VS_Code-Install_Server-0098FF?style=flat-square" alt="Install in VS Code" height="28"></a> <a href="https://lmstudio.ai/install-mcp?name=web-researcher&config=eyJjb21tYW5kIjoidXZ4IiwiYXJncyI6WyJ3ZWItcmVzZWFyY2hlci1tY3AiXX0%3D"><img src="https://img.shields.io/badge/LM_Studio-Add_MCP-4A2DB8?style=flat-square" alt="Add to LM Studio" height="28"></a> </p>

The Cursor / VS Code / LM Studio buttons install the zero-config uvx setup (your editor prompts to confirm before adding it; needs uv — see above). It runs DuckDuckGo web search with no API key — great to try instantly; image_search/news_search and richer providers need a key (2 min, see Configuration). Claude Desktop: download the .mcpb bundle for your platform and double-click it (Settings → Extensions), or use the uvx line above.

Using a different MCP client or want to pass API keys? See Connect to Your AI Assistant for the per-app config, and Configuration to pick a search provider.

Your AI can now search the web, read full articles, find academic papers, look up patents, and run multi-step research — only from sources you pick.

---

Why does this exist?

Perplexity gets its citations wrong over a third of the time. It links to papers that don't exist, invents DOIs, and presents SEO spam with the same confidence as peer-reviewed research. ChatGPT's web search isn't much better — it can't tell a blog post from a court filing.

If your work gets cited, published, submitted to a court, or shown to a client — you can't afford "probably real" sources.

This tool fixes the root cause: instead of searching the entire web and hoping, you tell your AI exactly which sources to search. We call these "search lenses" — curated lists of trusted sites for each field.

What you get	What that means for you
Search lenses — choose your sources by field	Your AI only sees the sites you trust (PubMed, SEC.gov, arXiv — not random blogs)
Research tools for every source type	Papers, patents, SEC filings, US court records, economic data, news, web pages, images, full-text reading, grounded answers with citations, structured extraction, and multi-step deep research
Always has a backup	Multiple search engines working together — if one has issues, the others pick up automatically
Reads full articles	Doesn't just give you snippets — extracts and reads entire pages, PDFs, Word docs, even YouTube transcripts and Hacker News threads
Real citations, formatted	Every source comes with a proper APA/MLA citation and a link that actually works
Your queries stay private	Runs on your machine — nobody sees what you're researching. Not us, not anyone.
Paper trail	Every search is logged so you can reproduce your research process months later

Works with Claude, Claude Desktop, Cursor, and any AI assistant that supports tool use.

Who uses this

• Academic researchers — "I need a literature review with real DOIs, not made-up citations"
• Business analysts — "My deliverable needs sources a client can actually click and verify"
• Lawyers — "If I cite a case that doesn't exist, I get fined $50,000"
• Journalists — "I need to cross-check government records and court filings, not Perplexity summaries"
• Medical researchers — "Clinical decisions based on a health blog could hurt someone"
• Graduate students — "I spent 3 hours tracking down a citation my AI invented"
• Enterprise teams — "Our competitive research can't go through a third party's servers"

---

---

How It Compares

	web-researcher-mcp	Perplexity	Scite.ai	Elicit
You pick which sources are searched	Yes (built-in + custom lenses)	No	No	No
Makes up citations	Never — every link is real	~37% incorrect	Rare (journals only)	Rare
Works across all fields	Yes — legal, medical, news, patents, everything	Yes	Journals only	Papers only
Keeps your research private	Yes — runs on your machine	No (they see everything)	No	No
Works inside your existing AI (Claude, Cursor, etc.)	Yes	No (separate app)	Partially	No (separate app)
Can read full articles, not just snippets	Yes — pages, PDFs, Word docs, YouTube	No	No	Limited
Cost	Free forever (open source)	$20/mo	$20/mo	$10-49/mo

When to use what

• Perplexity — Quick casual lookups where you don't need to cite your sources
• Scite.ai / Elicit — Browsing a specific database of academic papers
• web-researcher-mcp — Anything where your reputation is attached to the research: client work, court filings, publications, grant proposals, medical decisions, journalism
• Claude built-in search — Quick one-off lookups mid-conversation

---

What your AI can do with this

Tool	What it does
web_search	Search the web — optionally restricted to only the sources you trust via lenses
scrape_page	Read any URL in full — web pages, PDFs, Word docs, slideshows, YouTube transcripts, Hacker News threads (read natively via the HN API); supports mode: raw for verbatim, unsanitized source (e.g. inspecting JSON or HTML)
search_and_scrape	Search and then read the best results — with quality scoring to surface the most reliable sources
image_search	Find images by size, type, color, or format
news_search	Search recent news with date controls and source filtering
academic_search	Find real papers with real DOIs — authors, citation counts, open-access links
paper_fulltext	Fetch a paper's full text in one call from its DOI, Semantic Scholar ID, or URL — no need to chain academic_search then scrape_page
citation_graph	Walk a paper's citation neighborhood — works it cites and works that cite it, with intent/influence signals
patent_search	Search patent offices (US, Europe, international) with classification codes
filing_search	Search SEC EDGAR for US public-company filings (10-K, 10-Q, 8-K, …) — or pull structured XBRL company facts
legal_search	Search US court opinions and dockets via CourtListener — real cases with real citations
econ_search	Look up economic data — World Bank global development indicators, OECD economic indicators, Eurostat European statistics (all keyless), and FRED US macro series (GDP, CPI, unemployment, rates; requires FRED_API_KEY)
clinical_search	Search ClinicalTrials.gov — clinical-trial registrations with status, phase, sponsor, and whether results are posted (discovery, not medical advice)
monarch_search	Query the Monarch Initiative biomedical knowledge graph — rank diseases and genes by phenotype similarity, look up disease/gene/phenotype entities, traverse gene-disease-phenotype associations
awesome_list_search	Search the ecosyste.ms Awesome API for community-curated "awesome-*" lists on a GitHub topic — structured, filterable coverage (stars, curated-entry count, topics) beyond free-text search
local_search	Search for physical places (restaurants, shops, services, points of interest) by local intent query — structured POI details and descriptions. Requires BRAVE_API_KEY
brand_research	Research a company's complete brand identity — colors (hex), logos, typography, tone of voice, and social handles — from any domain or company name. Returns structured JSON for AI content generation. No API key required; BrandFetch key optional for richer data
company_recon	OSINT company reconnaissance — Certificate Transparency log SANs, Wayback Machine historical URL inventory, derived subdomains, and a web-search company summary. Each phase fails soft and is independently selectable
verify_citation	Check a citation before you rely on it — does it exist, match a real record, and is it retracted or a dead link? Evidence, not a verdict
audit_bibliography	Audit a whole reference list in one pass — paste a CSL-JSON/RIS/BibTeX file (or a session) and get per-entry + corpus-level flags for retracted, dead-link, and unverifiable citations
verify_recommendation	Audit an AI-generated recommendation list (listicle, product ranking) for self-promotion, author conflicts of interest, domain reputation, and dead links — catches GEO-gamed picks. Evidence, not a verdict
archive_source	Capture a fresh Internet Archive (Wayback Machine) snapshot of a URL via Save Page Now so a cited source stays verifiable if the page later changes or disappears — returns snapshot URL + timestamp (write tool)
sequential_search	Multi-step deep research — your AI remembers what it already found and builds on it
get_research_session	Recover a research session after context loss — picks up right where you left off
research_export	Export a research session as a shareable report (markdown or JSON), with full per-step provenance
format_bibliography	Turn collected sources into a formatted bibliography — APA, MLA, BibTeX, RIS, or CSL-JSON (Zotero/EndNote/Mendeley-ready)
research_panel	Ask the same question to a panel of independently configured LLMs and compare answers — consensus, contradictions, and model-unique points, computed deterministically, never smoothed over by an arbiter model

Most tools above are always available. A few activate only when the right provider or config is present: citation_graph and research_panel require at least one configured backing provider; filing_search requires EDGAR_CONTACT_EMAIL; local_search requires BRAVE_API_KEY. Operators can also enable opt-in, consent-gated tools (per-user analytics, long-term memory, shared workspaces, saved-query monitoring) that appear only when their feature is turned on — see docs/TOOLS.md for the authoritative, CI-verified tool list and full schemas.

Ready-made research templates

The server also ships guided prompt templates your AI assistant can pull in with one click — they walk it through a proven, multi-step process so you don't have to spell out every instruction:

Template	What it guides your AI to do
comprehensive-research	Run a structured, multi-step deep dive on a topic
fact-check	Verify a claim against multiple independent sources
competitive-analysis	Size up a company and its market (news, patents, web)
literature-review	Systematically review academic literature on a topic
brand-guidelines	Research a brand and produce use-case-specific creative direction (landing page, email, video brief) — calls brand_research and interprets the structured JSON for you
company-recon	Deep OSINT reconnaissance on a company — maps infrastructure, filings, personnel, and public footprint
curriculum-research	Research a subject's syllabus coverage, institutional climate, and academic-freedom context — calls web_search with the curriculum lens

In most AI apps these show up wherever you pick a prompt or "/" command. The server exposes live status resources (stats://tools, stats://sessions, stats://rate-limits, stats://providers), a lens catalog (lenses://catalog), diagnostics (diagnostics://errors/recent, diagnostics://health), and a large-payload artifact store (research://artifact/{id}) so you — or your AI — can check usage, limits, and which providers are active. See docs/DEPLOYMENT.md for the full list.

---

Quick Start

Option 1: Homebrew (macOS / Linux — recommended)

brew install zoharbabin/tap/web-researcher-mcp
claude mcp add --scope user web-researcher -- web-researcher-mcp

Homebrew handles trust, updates, and PATH for you — no signing warnings.

Option 2: One-command install (any OS — no dev tools needed)

macOS / Linux:

curl -fsSL https://raw.githubusercontent.com/zoharbabin/web-researcher-mcp/main/install.sh | sh

Windows (PowerShell):

powershell -ExecutionPolicy Bypass -c "irm https://raw.githubusercontent.com/zoharbabin/web-researcher-mcp/main/install.ps1 | iex"

Downloads the binary, verifies its SHA-256 checksum against the signed release, puts it on your PATH, and registers it with Claude Code if installed. Customize the install location:

INSTALL_DIR=/opt/tools curl -fsSL https://raw.githubusercontent.com/zoharbabin/web-researcher-mcp/main/install.sh | sh

<details> <summary><strong>Other install methods</strong></summary>

AUR (Arch Linux):

# Using any AUR helper (yay, paru, etc.)
yay -S web-researcher-mcp

Or manually: git clone https://aur.archlinux.org/web-researcher-mcp.git && cd web-researcher-mcp && makepkg -si

Nix / NixOS:

# Run without installing
nix run github:zoharbabin/web-researcher-mcp

# Add to your flake inputs
nix profile install github:zoharbabin/web-researcher-mcp

See packaging/nix/flake.nix for NixOS module usage.

Continue.dev:
Add to your Continue ~/.continue/config.json:

{
  "mcpServers": {
    "web-researcher": {
      "command": "uvx",
      "args": ["web-researcher-mcp"]
    }
  }
}

Or copy packaging/continue/config.json as a starting point.

WinGet (Windows):

winget install zoharbabin.web-researcher-mcp

Scoop (Windows):

scoop bucket add zoharbabin https://github.com/zoharbabin/scoop-bucket
scoop install web-researcher-mcp

Chocolatey (Windows):

choco install web-researcher-mcp

Homebrew Cask (macOS — Developer ID-signed + notarized binary):

brew install --cask zoharbabin/tap/web-researcher-mcp

The cask ships the notarized darwin binary (Gatekeeper-clean). Most users want the formula above (brew install zoharbabin/tap/web-researcher-mcp), which the bare name resolves to; pass --cask explicitly for the notarized artifact.

Go install (if you have Go):

go install github.com/zoharbabin/web-researcher-mcp/cmd/web-researcher-mcp@latest
claude mcp add --scope user web-researcher -- web-researcher-mcp

Docker:

# STDIO mode needs -i so the container's stdin stays attached for MCP JSON-RPC
docker run -i --rm \
           -e GOOGLE_CUSTOM_SEARCH_API_KEY=YOUR_KEY \
           -e GOOGLE_CUSTOM_SEARCH_ID=YOUR_CX \
           docker.io/zoharbabin/web-researcher-mcp:latest

Build from source:

git clone https://github.com/zoharbabin/web-researcher-mcp.git
cd web-researcher-mcp
go build -o web-researcher-mcp ./cmd/web-researcher-mcp

</details>

Connect to Your AI Assistant

The install script registers with Claude Code automatically. For other apps, add to your AI's config file:

{
  "mcpServers": {
    "web-researcher": {
      "command": "web-researcher-mcp",
      "env": {
        "GOOGLE_CUSTOM_SEARCH_API_KEY": "YOUR_GOOGLE_API_KEY",
        "GOOGLE_CUSTOM_SEARCH_ID": "YOUR_SEARCH_ENGINE_ID"
      }
    }
  }
}

Any provider works — pick one and set its key. For example, Brave (no Google keys needed):

{
  "mcpServers": {
    "web-researcher": {
      "command": "web-researcher-mcp",
      "env": {
        "SEARCH_PROVIDER": "brave",
        "BRAVE_API_KEY": "YOUR_BRAVE_API_KEY"
      }
    }
  }
}

Swap in any provider from the Configuration table by setting SEARCH_PROVIDER and that provider's key. Done — your AI assistant now has access to all research tools.

---

Configuration

No API key required. DuckDuckGo is the built-in zero-config fallback — install and go. To raise result quality and unlock image/news search, add any one of the providers below. They're all optional and interchangeable — pick whichever you already use or prefer; the server treats them equally.

Search providers

Set SEARCH_PROVIDER=<name> and supply that provider's key. Every provider works with search lenses, and any of them can be combined for automatic failover (see Search Providers).

Provider	SEARCH_PROVIDER	Key variable(s)	Get a key
DuckDuckGo	duckduckgo	none	Built in — zero config
Google PSE	google	GOOGLE_CUSTOM_SEARCH_API_KEY + GOOGLE_CUSTOM_SEARCH_ID	cloud console + engine
Brave	brave	BRAVE_API_KEY	brave.com/search/api
Serper	serper	SERPER_API_KEY	serper.dev
SearchAPI.io	searchapi	SEARCHAPI_API_KEY	searchapi.io
You.com	youcom	YOUDOTCOM_API_KEY	you.com/docs/api-reference/search/v1-search
SearXNG	searxng	SEARXNG_URL	self-hosted
Tavily	tavily	TAVILY_API_KEY	app.tavily.com
Exa	exa	EXA_API_KEY	dashboard.exa.ai
Hacker News	hackernews	none	Built in — zero config (HN Algolia index)
Reddit	reddit	none	Built in — zero config (public RSS)
Bluesky	bluesky	none	Built in — zero config (public AT Protocol API)
GitHub	github	none (GITHUB_TOKEN optional, raises rate limit)	Built in — zero config (public REST Search API)
Xquik	xquik	XQUIK_API_KEY	dashboard.xquik.com

Each provider has its own free tier, signup flow, and capability mix (images, news, freshness). See docs/PROVIDERS.md for a full comparison (index classification, capability matrix, quick-pick guide) and docs/API_SETUP.md for step-by-step key setup. Set up more than one and the server fails over automatically — see Search Providers.

When SEARCH_PROVIDER is unset, the server uses Google if its keys are present and otherwise falls back to the zero-config DuckDuckGo provider — so it always works out of the box, with or without keys.

Academic Search (Optional — no signup needed)

Academic search providers (OpenAlex, CrossRef) accept a contact email to unlock faster access via the polite pool — no registration, just an email. See docs/API_SETUP.md for setup and docs/DEPLOYMENT.md for the full variable reference.

With these set, academic_search returns real papers with DOIs, authors, citation counts, and open-access PDF links. Without them, it still works but uses web search as a fallback.

Patent Search (Optional)

Patent providers (EPO, USPTO, The Lens) require API keys for structured patent data. See docs/API_SETUP.md for step-by-step setup and docs/DEPLOYMENT.md for the full variable reference.

With these, patent_search returns structured patent data with classification codes, dates, and inventors. Without them, it falls back to web search.

<details> <summary><strong>Advanced: HTTP mode, OAuth, and all other settings</strong></summary>

HTTP mode, OAuth, rate limiting, cache, scraping, and observability settings are documented in docs/DEPLOYMENT.md.

</details>

---

Under the Hood

<details> <summary><strong>Architecture (for developers and contributors)</strong></summary>

The full per-package map and the layered diagram (MCP transports → tool dispatch → service layer → infrastructure) live in ARCHITECTURE.md — kept in one place to avoid drift.

<details> <summary><strong>Design Principles (for developers)</strong></summary>

1. Zero global state -- all dependencies injected via constructors
2. Interface-driven -- every external dependency behind an interface for testing and swapping
3. Bounded concurrency -- explicit semaphores for external API calls
4. Defense in depth -- SSRF protection, rate limiting, content sanitization at every layer
5. Fail loud -- errors returned, never swallowed; validation at boundaries

</details> </details>

---

Search Providers

You choose which search engine powers your research. All of them work with lenses.

Provider	Whole-Web	Images	News	Notes
DuckDuckGo	Yes	—	—	Zero-config default (no API key needed); rate-limited for heavy use
Google PSE	Yes	Yes	Yes	Programmable Search Engine; free tier: 100 queries/day
Brave Search	Yes	Yes	Yes	Independent index; free tier available
Serper.dev	Yes	Yes	Yes	Google-identical results
SearXNG	Yes	Yes	Yes	Self-hosted, privacy-first, air-gapped deployments
SearchAPI.io	Yes	Yes	Yes	Unified API with multiple engine backends
Tavily	Yes	—	Yes	AI-agent search; clean, LLM-ready content
Exa	Yes	—	Yes	Neural/semantic search; also backs academic_search and the optional paid scrape tier
Hacker News	HN only	—	Yes	Zero-config (HN Algolia index); searches HN threads, not the full web
Reddit	Reddit only	—	Yes	Zero-config (public RSS); searches Reddit posts, not the full web
Bluesky	Bluesky only	—	—	Zero-config (public AT Protocol API); searches Bluesky posts, not the full web
GitHub	GitHub only	—	Yes	Zero-config (public REST Search API); searches issues/PRs, not the full web

Multiple Providers (recommended)

Set up multiple search engines so if one has issues, your research doesn't stop:

export SEARCH_ROUTING=brave,google,serper

If Brave is down, it automatically tries Google. If Google is rate-limited, it falls through to Serper. Your research just works.

See docs/PROVIDERS.md for a full provider comparison (index classification, capabilities, free tiers) and docs/DEPLOYMENT.md for advanced routing options (per-topic routing, patent-specific providers, etc.).

Single Provider

If you only have one search API key, that works too — just set it up and go.

<details> <summary><strong>Provider Setup Examples</strong></summary>

Multi-provider routing (recommended):

export SEARCH_ROUTING=brave,google,serper
export BRAVE_API_KEY=BSAxxxxxxxxxx
export GOOGLE_CUSTOM_SEARCH_API_KEY=AIza...
export GOOGLE_CUSTOM_SEARCH_ID=017...
export SERPER_API_KEY=...

Single provider — Brave Search:

export SEARCH_PROVIDER=brave
export BRAVE_API_KEY=BSAxxxxxxxxxx

Single provider — SearXNG (self-hosted, privacy-first):

export SEARCH_PROVIDER=searxng
export SEARXNG_URL=http://localhost:8080

Single provider — Exa:

export SEARCH_PROVIDER=exa
export EXA_API_KEY=...

Single provider — Google PSE:

export SEARCH_PROVIDER=google
export GOOGLE_CUSTOM_SEARCH_API_KEY=AIza...
export GOOGLE_CUSTOM_SEARCH_ID=017...

Any provider from the Configuration table works the same way — set SEARCH_PROVIDER and its key(s).

</details>

---

Search Lenses

Search lenses let you control which websites your AI is allowed to search. Instead of searching the entire web (and getting blogs, spam, and AI-generated junk), a lens restricts results to only the sources you trust for that topic.

Built-in Lenses

Lens	Focus
docs	Official documentation and API references only
academic	Preprint servers, repositories, open-access journals
academic-extended	Preprint servers, OA aggregators, and repositories beyond core journal indexes
biomed	Rare-disease and biomedical knowledge-graph sources — ontology portals, gene-disease databases, curated rare-disease registries
clinical	Clinical trials, drug safety, evidence-based medicine
curriculum	Academic curriculum data, institutional free speech climate, and global education statistics
security	CVEs, advisories, vulnerability research
investigative_records	Public records, corporate filings, FOIA
programming	Code docs, tutorials, Q&A
programming-goggle	Developer-first results re-ranked by Brave's Programming Goggle — surfaces docs, repos, and authoritative technical content (requires Brave)
devops	Infrastructure and operations — Kubernetes, Docker, Terraform, cloud, CI/CD
news	Current events, journalism
tech	Technology industry
legal	Law, cases, statutes
medical	Health, medicine
finance	Markets, filings
science	Research, papers
government	Policy, regulations
osint	Open-source intelligence — public records, corporate registries, social footprint, infrastructure
awesome-lists	Community-curated "awesome-*" lists on GitHub — PR-reviewed tool and resource collections across every domain

You can also create your own lenses for any field — just list the domains you trust.

How it works

When you (or your AI) use a lens, results come only from the sites in that lens. For example, using the medical lens means your AI searches PubMed, WHO, NIH, and other clinical sources — never health blogs or supplement ads.

Your AI uses lenses automatically when you ask it to. For example: "Search for recent findings on SGLT2 inhibitors using the clinical lens."

<details> <summary><strong>Creating Your Own Lens</strong></summary>

Create a directory for your custom lenses and add a JSON file for each one:

{
  "name": "my-industry",
  "description": "Only searches sources I trust for my field",
  "domains": [
    "trusted-source.com",
    "industry-journal.org",
    "official-database.gov"
  ],
  "cx": "",
  "routing": ""
}

Then point the server to your lens directory:

export CUSTOM_LENSES_PATH=/path/to/my-lenses

Your AI will now have my-industry as an available lens. Custom lenses load after the built-in set — a custom lens with the same name as a built-in one overrides it. You can add up to ~10 domains per lens.

Advanced options (optional — most users can ignore these):

• cx — If you have a Google Programmable Search Engine with up to 5,000 domains, put the engine ID here
• routing — Force this lens to use a specific search provider (e.g., "google")

</details>

---

Privacy & Security

Your research queries go directly from your machine to the search provider you chose. They never pass through our servers (we don't have servers). The tool runs entirely on your computer.

<details> <summary><strong>Technical security details (for enterprise / compliance teams)</strong></summary>

• SSRF protection — blocks internal network access, cloud metadata endpoints, DNS rebinding attacks
• OAuth 2.1 (HTTP mode) — JWKS token validation, per-tenant isolation, audience/issuer validation
• Rate limiting (HTTP mode) — per-tenant + global limits to protect upstream APIs
• Content sanitization — HTML cleaned via whitelist policy, deduplication, quality scoring

For the full threat model, see docs/SECURITY.md.

</details>

---

Setup for Each AI App

Claude Code

Add to your MCP config (~/.claude.json). Set SEARCH_PROVIDER and the matching key for whichever provider you use (see the Configuration table) — this example uses Google:

{
  "mcpServers": {
    "web-researcher": {
      "command": "/path/to/web-researcher-mcp",
      "env": {
        "SEARCH_PROVIDER": "google",
        "GOOGLE_CUSTOM_SEARCH_API_KEY": "AIza...",
        "GOOGLE_CUSTOM_SEARCH_ID": "017..."
      }
    }
  }
}

Claude Desktop

Add to ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows):

{
  "mcpServers": {
    "web-researcher": {
      "command": "/path/to/web-researcher-mcp",
      "env": {
        "GOOGLE_CUSTOM_SEARCH_API_KEY": "AIza...",
        "GOOGLE_CUSTOM_SEARCH_ID": "017..."
      }
    }
  }
}

Cursor

Add to .cursor/mcp.json in your project root:

{
  "mcpServers": {
    "web-researcher": {
      "command": "/path/to/web-researcher-mcp",
      "env": {
        "GOOGLE_CUSTOM_SEARCH_API_KEY": "AIza...",
        "GOOGLE_CUSTOM_SEARCH_ID": "017..."
      }
    }
  }
}

HTTP Mode (Teams / Shared Server)

For teams that want one shared instance everyone connects to:

PORT=3000 \
OAUTH_ISSUER_URL=https://auth.example.com \
OAUTH_AUDIENCE=https://api.example.com \
./web-researcher-mcp

Then connect any AI app to http://localhost:3000/mcp/.

<details> <summary><strong>Docker Compose Example</strong></summary>

services:
  web-researcher:
    image: zoharbabin/web-researcher-mcp
    ports:
      - "3000:3000"
    environment:
      PORT: "3000"
      SEARCH_PROVIDER: brave
      BRAVE_API_KEY: ${BRAVE_API_KEY}

</details>

Note: Tool behavior is identical across all connection modes (STDIO and HTTP). The only differences are auth (HTTP requires OAuth) and rate limiting (HTTP enforces per-tenant limits; STDIO has only upstream API quotas). See docs/DEPLOYMENT.md for details.

---

Performance

Searches come back in under a second. Previously-seen results are cached so repeats are instant. Full article extraction works on 95%+ of the web — including sites that try to block bots. Heavy JavaScript sites get a real browser behind the scenes (automatic, no setup needed).

---

Development

go build -o web-researcher-mcp ./cmd/web-researcher-mcp   # Build
go test -race ./...                                        # Test (with race detector)
make verify                                                # Full CI gate (see Makefile for steps)

The lint, gosec, and govulncheck tools are pinned as go.mod tool directives, so make verify runs them at the exact versions CI uses (no global installs needed). Branch protection requires the Lint, Test, Security, and E2E checks to pass.

See CONTRIBUTING.md for the full development workflow, code style guide, and PR process.

---

Troubleshooting

<details> <summary><strong>Server starts but tools fail with "API key" errors</strong></summary>

The server starts even with missing credentials (to allow MCP handshake). Set your API keys in the env block of your MCP client config, not in your shell profile.

</details> <details> <summary><strong>Some pages come back empty</strong></summary>

For JavaScript-heavy sites, the tool uses a real browser (Chromium). With the binary install it auto-downloads on first use (~200MB). If you already have Chrome installed, set CHROME_PATH to point to it. The Docker image ships with Chromium bundled (CHROME_PATH preset), so JavaScript rendering works out of the box — no download.

</details> <details> <summary><strong>Cache serving stale results after upgrade</strong></summary>

The disk cache lives at your OS cache directory (e.g., ~/Library/Caches/web-researcher-mcp/ on macOS, ~/.cache/web-researcher-mcp/ on Linux). Delete that directory to clear it, or set CACHE_DIR to a custom path.

</details> <details> <summary><strong>Hitting search limits (429 errors)</strong></summary>

If your provider's free tier runs out (e.g. Google PSE allows 100 searches/day):

• Switch to a different provider — set SEARCH_PROVIDER to any other option (see Configuration); each has its own free tier
• Set up multiple providers (e.g. SEARCH_ROUTING=brave,google) — if one is rate-limited, it automatically falls through to the next
• Or upgrade your provider's plan

</details> <details> <summary><strong>macOS: "Failed to reconnect" / error -32000 after a manual update</strong></summary>

This happens only if you replaced the binary by copying new bytes over the existing file in place (cp new /path/to/web-researcher-mcp). On Apple Silicon, macOS caches the binary's ad-hoc code signature against the file, and overwriting it in place can make the next launch get killed before it starts. The official installers (Homebrew, the one-command install.sh, and the Claude Code plugin) avoid this by installing to a fresh file. To fix a manual install, replace it cleanly and re-sign:

rm -f /path/to/web-researcher-mcp
cp /path/to/new-build /path/to/web-researcher-mcp
codesign --force -s - /path/to/web-researcher-mcp   # ad-hoc re-sign

Then reconnect your client. (Re-running install.sh does this correctly for you.)

</details>

---

Contributing

Contributions are welcome. Please see CONTRIBUTING.md for code style guidelines, development workflow, and how to submit pull requests.

---

Documentation

Document	Description
ARCHITECTURE.md	Design decisions, technology stack, dependencies
CONTRIBUTING.md	Development setup, code style, PR workflow
docs/TOOLS.md	Tool specifications and parameter schemas
docs/EXAMPLES.md	Usage examples with JSON tool calls
docs/API_SETUP.md	Search provider API key setup for all providers
docs/SECURITY.md	Threat model, SSRF, auth, compliance (SOC2/GDPR/FedRAMP)
docs/PRIVACY.md	What data goes where, third-party processors, retention
docs/DEPLOYMENT.md	Build, Docker, Kubernetes, client configs, scaling
docs/PYTHON_CLIENT.md	Python SDK — WebResearcherClient reference, sync wrapper, installation
docs/LESSONS_LEARNED.md	Node.js to Go migration story and lessons
docs/SESSION_PERSISTENCE.md	How sessions survive context loss — design, data flow, citations
docs/MIGRATION.md	Migrating from the deprecated google-researcher-mcp

---

License

MIT

---

<p align="center"> Built by <a href="https://zoharbabin.com">Zohar Babin</a>, with <a href="https://go.dev">Go</a> and the <a href="https://modelcontextprotocol.io/">Model Context Protocol</a> </p>