How do I install MCP Retrieval?

Copy the stdio config for Cursor, Claude Desktop, Claude Code, or VS Code on this page. It uses the publisher's install, not a PlugMCP proxy.

Does MCP Retrieval need an API key?

The publisher lists these environment variables: MCP_TRANSPORT, MCP_NAME, MCP_PATH, SERVER_PORT, SERVER_READ_TIMEOUT, SERVER_WRITE_TIMEOUT, LOG_MODE, MAX_IDLE_CONNS_PER_HOST, MAX_QUERIES, DEFAULT_RESULTS, MAX_RESULTS, DEFAULT_IMAGES, MAX_IMAGES, DEFAULT_TIMEOUT_MS, MIN_TIMEOUT_MS, MAX_TIMEOUT_MS, DEFAULT_DOCUMENT_CHARS, MAX_DOCUMENT_CHARS, PROXY_SCHEME, PROXY_HOST, PROXY_PORT, PROXY_LOGIN, PROXY_PASSWORD.

What transport does MCP Retrieval use?

MCP Retrieval runs locally over stdio.

When was MCP Retrieval last checked?

Last checked 2026-10-27. Fast, idiomatic Go MCP server for web search, image search, and page scraping to Markdown. Runs locally, no API keys, free.

MCP Retrieval MCP サーバー

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The publisher's own command. Not a PlugMCP endpoint.

Add to Cursor Add to VS Code PlugMCP で実行

キーとログ付きでコピーをホスト。

Local command

docker run -i --rm ghcr.io/role1776/mcp-retrieval:0.1.10

Credentials from the publisher

MCP_TRANSPORT — stdio (client spawns the process) or http (streamable HTTP listener).
MCP_NAME — Server name reported in the MCP initialize handshake.
MCP_PATH — HTTP path the MCP endpoint is served on. Used only when MCP_TRANSPORT=http.
SERVER_PORT — TCP port to listen on. Used only when MCP_TRANSPORT=http.
SERVER_READ_TIMEOUT — HTTP read timeout as a Go duration. Used only when MCP_TRANSPORT=http.
SERVER_WRITE_TIMEOUT — HTTP write timeout as a Go duration. Used only when MCP_TRANSPORT=http.
LOG_MODE — local (text, debug) or prod (JSON, info). Logs go to stderr.
MAX_IDLE_CONNS_PER_HOST — Idle connections the outbound HTTP client keeps per host.
MAX_QUERIES — Maximum queries or URLs accepted in one call.
DEFAULT_RESULTS — Snippets returned per query when the call does not ask for a count.
MAX_RESULTS — Upper bound for snippets per query.
DEFAULT_IMAGES — Images returned per query when the call does not ask for a count.
MAX_IMAGES — Upper bound for images per query.
DEFAULT_TIMEOUT_MS — Per-call timeout in milliseconds when the call does not request one.
MIN_TIMEOUT_MS — Lowest timeout a call may request, in milliseconds.
MAX_TIMEOUT_MS — Highest timeout a call may request, in milliseconds.
DEFAULT_DOCUMENT_CHARS — Characters kept per scraped page when the call does not ask for a limit.
MAX_DOCUMENT_CHARS — Upper bound for characters kept per scraped page.
PROXY_SCHEME — Outbound proxy scheme. Optional; set all five PROXY_* variables or none.
PROXY_HOST — Outbound proxy host. Enables per-request rotating proxy sessions.
PROXY_PORT — Outbound proxy port. Required when PROXY_HOST is set.
PROXY_LOGIN — Outbound proxy username. Required when PROXY_HOST is set.
PROXY_PASSWORD — Outbound proxy password. Required when PROXY_HOST is set.

Claude Code has no install link for a local command. Copy the command below and run it in a terminal.

shClaude Code

1MCP_TRANSPORT=<value> MCP_NAME=<value> MCP_PATH=<value> SERVER_PORT=<value> SERVER_READ_TIMEOUT=<value> SERVER_WRITE_TIMEOUT=<value> LOG_MODE=<value> MAX_IDLE_CONNS_PER_HOST=<value> MAX_QUERIES=<value> DEFAULT_RESULTS=<value> MAX_RESULTS=<value> DEFAULT_IMAGES=<value> MAX_IMAGES=<value> DEFAULT_TIMEOUT_MS=<value> MIN_TIMEOUT_MS=<value> MAX_TIMEOUT_MS=<value> DEFAULT_DOCUMENT_CHARS=<value> MAX_DOCUMENT_CHARS=<value> PROXY_SCHEME=<value> PROXY_HOST=<value> PROXY_PORT=<value> PROXY_LOGIN=<secret> PROXY_PASSWORD=<secret> claude mcp add role1776-mcp-retrieval -- docker run -i --rm ghcr.io/role1776/mcp-retrieval:0.1.10

Run in a terminal.

jsonClaude Desktop

1{2  "mcpServers": {3    "role1776-mcp-retrieval": {4      "command": "docker",5      "args": [6        "run",7        "-i",8        "--rm",9        "ghcr.io/role1776/mcp-retrieval:0.1.10"10      ],11      "env": {12        "MCP_TRANSPORT": "<value>",13        "MCP_NAME": "<value>",14        "MCP_PATH": "<value>",15        "SERVER_PORT": "<value>",16        "SERVER_READ_TIMEOUT": "<value>",17        "SERVER_WRITE_TIMEOUT": "<value>",18        "LOG_MODE": "<value>",19        "MAX_IDLE_CONNS_PER_HOST": "<value>",20        "MAX_QUERIES": "<value>",21        "DEFAULT_RESULTS": "<value>",22        "MAX_RESULTS": "<value>",23        "DEFAULT_IMAGES": "<value>",24        "MAX_IMAGES": "<value>",25        "DEFAULT_TIMEOUT_MS": "<value>",26        "MIN_TIMEOUT_MS": "<value>",27        "MAX_TIMEOUT_MS": "<value>",28        "DEFAULT_DOCUMENT_CHARS": "<value>",29        "MAX_DOCUMENT_CHARS": "<value>",30        "PROXY_SCHEME": "<value>",31        "PROXY_HOST": "<value>",32        "PROXY_PORT": "<value>",33        "PROXY_LOGIN": "<secret>",34        "PROXY_PASSWORD": "<secret>"35      }36    }37  }38}

claude_desktop_config.json

Local · ociPublisher installStep-by-step: add this in Claude

Remote URL or a command on your machine? How the two installs differ

Tools

No tool list yet. Remote servers get one after the first health check.

FAQ

Questions

What it is

mcp-retrieval is a Model Context Protocol server written in Go. It exposes web retrieval capabilities to any MCP-compatible client (Claude Desktop, IDE agents, custom LLM apps) as three read-only tools. Under the hood it uses the retrieval-go library to search the web and fetch pages, returning results as clean Markdown ready to hand to a model.

The library needs no API keys: web search goes through DuckDuckGo Lite, image search through Bing Images, and page fetching runs the HTML through a readability extractor before converting it to Markdown. To stay reliable against bot protection it impersonates real browsers at the TLS level and can rotate both browser fingerprints and proxies — see Retrieval engine.

Both transports the MCP SDK supports are available and expose the identical tool set:

stdio — the client launches the binary and talks over stdin/stdout (the default, ideal for desktop clients).
http — a long-running streamable HTTP server (useful for remote/shared deployments).

Tools

Tool	Description
`web_search`	Runs one or more queries in parallel and returns per-query deduplicated, reranked snippets with links.
`web_search_images`	Runs one or more image queries in parallel and returns per-query deduplicated image results.
`web_scrape`	Downloads one or more pages in parallel and returns the main article text as Markdown.

All three are annotated as read-only. Each tool returns a structured JSON payload that matches its output schema; the SDK mirrors the same JSON into the text content block for clients that do not read structuredContent.

`web_search`

Parameter	Type	Default	Notes
`queries`	`[]string`	—	Required. Executed in parallel.
`max_results`	`int`	`5`	Snippets per query, capped at `max_results` config (`20`).
`timeout_ms`	`int64`	`5000`	Whole-call timeout; clamped to `[min, max]` from config.
`date`	`string`	—	Freshness filter: `d` (day), `w` (week), `m` (month), `y` (year).

`web_search_images`

Parameter	Type	Default	Notes
`queries`	`[]string`	—	Required. Executed in parallel.
`max_images`	`int`	`5`	Images per query, capped at `max_images` config (`10`).
`timeout_ms`	`int64`	`5000`	Whole-call timeout; clamped to `[min, max]` from config.
`date`	`string`	—	Freshness filter: `d` / `w` / `m` / `y`.

`web_scrape`

Parameter	Type	Default	Notes
`urls`	`[]string`	—	Required. Downloaded in parallel.
`robots_txt`	`bool`	`false`	Respect the page's `robots.txt`.
`timeout_ms`	`int64`	`5000`	Whole-call timeout; clamped to `[min, max]` from config.
`remove_links`	`bool`	`false`	Strip Markdown links from the text.
`max_chars`	`int`	`20000`	Truncate page text to N characters, capped at `max_document_chars` config (`20000`).

Both queries/urls lists are capped at max_queries (10) items per call. Queries must be ≤ 512 characters; URLs ≤ 2048 characters and http/https only.

Results and counts

Every call fans out across the input list and returns one entry per query/URL, each with its own status — success, failed, or timeout — so a partial failure still returns the items that did work.

count is the number of items actually returned, and it can be lower than the requested max_results / max_images: duplicates within a single query's results are removed before the limit is applied, and the upstream may simply have fewer items to give. A smaller count is a normal outcome, not an error.

Deduplication is per query, not across queries. Each entry is deduplicated on its own, so a link found by two of the queries in the same call appears in both entries — dedupe the union yourself if you need it.

Errors

Request-level failures are returned as a tool result with isError: true and a plain-text message, not as a JSON-RPC error — the model reads the message and can correct the call itself. Per-item failures never do this; they stay inside the payload as status: "failed" / "timeout".

A call fails outright only when the input is rejected before any work starts, or when every item in it fails:

Message	Meaning
`invalid request`	The arguments did not pass validation.
`too many queries` / `too many urls`	The list exceeds `MAX_QUERIES`. Lists this long are normally rejected earlier by input-schema validation (the schema carries `maxItems`), so the client sees `validating "arguments": maxItems: ...` instead; this message is a fallback.
`query must not be empty`	An empty query, or an empty `queries` list.
`query is too long`	A query exceeds 512 characters.
`invalid url`	A URL is malformed, over 2048 characters, or not `http`/`https`.
`robots.txt denied`	`robots_txt: true` and the page disallows fetching.
`every url failed to be scraped; the pages may be unreachable or hold no extractable text`	Every URL failed with an error other than a timeout. Individual causes are logged to `stderr`, not returned.
`every query failed; the search upstream may be unreachable`	Every query failed with an error other than a timeout, including the upstream rejecting the requests (any non-200 answer, such as DuckDuckGo's HTTP 202 bot challenge under a burst of requests). The per-query cause is logged to `stderr`.
`request canceled`	The client canceled the call before it finished; nothing about the upstream is implied.
`internal server error`	Anything unclassified.

A timeout is never a call-level error: an item that runs out of time gets status: "timeout", and a call where every item timed out still returns all of them with that status. The all-failed messages only fire when no item succeeded or timed out.

Known limitations

web_scrape handles HTML only. Pages are run through a readability extractor, which needs article markup, so text/plain responses yield nothing and come back as status: "failed". Raw-file hosts are the common case: raw.githubusercontent.com, github.com/.../raw/..., cdn.jsdelivr.net. Scrape the rendered page instead of the raw file.
web_search_images relevance is not guaranteed. For some queries Bing Images serves a page that is not a result set, and it is parsed as though it were — the tool then returns unrelated images with status: "success". Treat image results as best-effort and verify them before showing them to a user.
No JavaScript. Pages are fetched as-is; content rendered client-side is invisible to the extractor.
Bursts of parallel searches can trip DuckDuckGo's bot challenge. The challenge answers with HTTP 202, which counts as a failed query, so queries keep failing until the request rate drops. A rotating proxy (see HTTP client and proxy) spreads the load across exit IPs.

Quick start

Install

Pick whichever fits — all of them give the identical server.

Container (no Go toolchain needed):

docker pull ghcr.io/role1776/mcp-retrieval:latest

Prebuilt binary — grab the archive for your platform from the latest release, unpack it, and put mcp-retrieval on your PATH.

MCP Bundle — for clients that install .mcpb files, download mcp-retrieval_<version>_<os>_<arch>.mcpb from the latest release and open it with your client. The bundle carries the compiled binary, so it needs neither Docker nor Go. Pick the file matching your OS and CPU architecture: a bundle holds one native binary.

From source:

go install github.com/Role1776/mcp-retrieval/app/cmd/mcp-retrieval@latest   # needs Go 1.25.5+

Or build the binary in place (the Go module lives in app/):

make build          # -> bin/mcp-retrieval

Run

# defaults: stdio transport, no configuration needed
./bin/mcp-retrieval

# with an explicit env file
./bin/mcp-retrieval -env /absolute/path/to/.env

The one flag is optional:

Flag	Meaning
`-env`	Path to a `.env` file. If omitted — or if the file does not exist — the server starts on defaults and whatever is already in the environment. There is no implicit lookup: under stdio the working directory is chosen by the MCP client, so a relative default would be unpredictable.

Connecting an MCP client (stdio)

Point your client at the built binary. Example Claude Desktop config:

{
  "mcpServers": {
    "retrieval": {
      "command": "/absolute/path/to/mcp-retrieval",
      "env": {
        "MAX_RESULTS": "20"
      }
    }
  }
}

The env block is optional — "command" alone is enough.

Connecting an MCP client (container)

Run the image on stdio. Configuration still travels through the env block, but Docker needs each variable named on the command line with -e for it to reach the process:

{
  "mcpServers": {
    "retrieval": {
      "command": "docker",
      "args": [
        "run", "-i", "--rm",
        "-e", "MAX_RESULTS",
        "-e", "DEFAULT_TIMEOUT_MS",
        "ghcr.io/role1776/mcp-retrieval:latest"
      ],
      "env": {
        "MAX_RESULTS": "20",
        "DEFAULT_TIMEOUT_MS": "5000"
      }
    }
  }
}

-i is required — without it the container gets no stdin and the client sees the server die immediately. Clients that install from the MCP Registry build this invocation themselves and prompt for the variables declared in server.json.

Running over HTTP

Set MCP_TRANSPORT=http and the server listens on SERVER_PORT at MCP_PATH (default http://localhost:8080/mcp).

Configuration

Everything is configured through environment variables, and each value is validated before startup: a non-numeric or non-positive value is a startup error (the *_IN_FLIGHT caps also accept 0). Relationships between limits are not checked at startup — see Limits. Variables already present in the environment win over a .env file, so an MCP client's env block always takes effect. Every field has a sensible default, so the server runs with no configuration at all (stdio transport).

See .env.example for the full list at its default values, ready to copy to .env.

MCP server

Env	Default	Notes
`MCP_TRANSPORT`	`stdio`	`stdio` or `http`.
`MCP_NAME`	`mcp-retrieval`	Server name advertised to clients.
`MCP_PATH`	`/mcp`	HTTP route (http transport only).

The version advertised to clients is not configurable: it is stamped into the binary at build time from the git tag.

HTTP server (http transport only)

Env	Default
`SERVER_PORT`	`8080`
`SERVER_READ_TIMEOUT`	`60s`
`SERVER_WRITE_TIMEOUT`	`60s`

HTTP client and proxy

Env	Default	Notes
`MAX_IDLE_CONNS_PER_HOST`	`100`	HTTP connection pooling.
`PROXY_HOST`	—	Optional. If set, requests are routed through a rotating-session proxy.
`PROXY_PORT`	—	Required when `PROXY_HOST` is set.
`PROXY_SCHEME`	—	Required when `PROXY_HOST` is set.
`PROXY_LOGIN`	—	Required when `PROXY_HOST` is set.
`PROXY_PASSWORD`	—	Required when `PROXY_HOST` is set.

When a proxy is configured, each outbound request gets a unique session id appended to the login, so the upstream provider rotates the exit IP per request.

Limits

Env	Default
`MAX_QUERIES`	`10`
`DEFAULT_RESULTS`	`5`
`MAX_RESULTS`	`20`
`DEFAULT_TIMEOUT_MS`	`5000`
`MAX_TIMEOUT_MS`	`10000`
`MIN_TIMEOUT_MS`	`1000`
`DEFAULT_IMAGES`	`5`
`MAX_IMAGES`	`10`
`DEFAULT_DOCUMENT_CHARS`	`20000`
`MAX_DOCUMENT_CHARS`	`20000`
`MAX_SEARCH_IN_FLIGHT`	`2`
`MAX_IMAGES_IN_FLIGHT`	`2`

MAX_SEARCH_IN_FLIGHT and MAX_IMAGES_IN_FLIGHT cap concurrent upstream web and image search requests per server process; 0 disables the cap.

Each value is checked on its own — it must be greater than zero, except the *_IN_FLIGHT caps, where 0 disables the cap — but the DEFAULT_*, MIN_* and MAX_* triples are not cross-checked against each other at startup. An inconsistent set does not stop the server; it is reconciled per request instead:

a value the caller omits, or passes as zero or negative, falls back to the matching DEFAULT_*;
the result is then clamped into [MIN_*, MAX_*], so a DEFAULT_* larger than its MAX_* simply yields MAX_*;
if MIN_* exceeds MAX_*, the maximum wins.

The effective limit is therefore always within the configured maximum, and misconfiguration degrades to a working server rather than a failed start. The trade-off is that it degrades silently: a typo such as MAX_RESULTS=2 instead of 20 produces no warning, only quietly smaller responses. Worth double-checking these values when results look truncated.

Logging

Env	Default	Notes
`LOG_MODE`	`local`	`local` → text handler at debug level; `prod` → JSON handler at info level. Logs go to `stderr`.

Architecture

The project follows a clean, layered structure. Dependencies point inward toward the domain, and each layer talks to the next through interfaces.

app/                       the Go module: sources plus its build files
                           (Dockerfile, .dockerignore, .goreleaser.yaml)

cmd/mcp-retrieval/main.go  entry point: parse flags, load config, run app

internal/
  app/                     wiring + lifecycle (build server, run, graceful shutdown)
  config/                  config loading (.env → env vars → validate)
  domain/                  core types (Query, Link, Document, Snippet, Image) and errors
  dto/web/                 request/response shapes for the MCP tools
  transport/mcp/           MCP layer
    router/                registers every tool group on the MCP server
    web/                   tool handlers
    utils/                 schema helpers and error → tool-result mapping
  usecase/web/             business logic: validation, parallelism, timeouts, dedupe/limit/rerank
  adapter/web/             retrieval-go client wiring (search, images, scrape, proxy)
  pkg/                     reusable building blocks (mcpserver, server, logger, validator)

Request flow for a tool call:

MCP client → transport/mcp/web (handler) → usecase/web → adapter/web → retrieval-go → the web
                     ↑ maps errors               ↑ validates, fans out, limits results

Search and scrape both fan out across the input list concurrently and aggregate per-item results, each with its own status (success, failed, timeout). A call only fails outright when every item in it fails with an error other than a timeout.

Retrieval engine

All network work is delegated to retrieval-go, configured in app/internal/adapter/web. Worth knowing:

Sources. Web search uses DuckDuckGo Lite; image search uses Bing Images; page fetching runs the raw HTML through a readability extractor and converts the main article to Markdown (tables included). No search-engine API keys are required.
Browser impersonation. The adapter enables WithBrowserRotation(), so each request is sent from one of ~11 real browser profiles picked at random. Every profile pairs a genuine TLS/JA3 fingerprint (via uTLS) with a matching User-Agent and client-hint headers — Chrome 133/131/120 (Windows/macOS/Linux), Edge 131, Firefox 120 (Windows/macOS), Safari 18.4 (macOS), and iOS 18.4 Safari. This makes the traffic look like ordinary browsers rather than a Go HTTP client, which is what keeps the free sources reachable.
Proxy rotation. When PROXY_HOST is configured, the adapter installs a proxy factory that appends a unique session-<id> to the proxy username on every request. With a session-based residential/rotating proxy provider, that yields a fresh exit IP per request, spreading load and avoiding rate limits. Without a proxy, requests go out directly.
Response handling. Responses are transparently decompressed (gzip, br, zstd, deflate), and keep-alive is disabled (WithDisableKeepAlive()) so pooled connections don't pin a single fingerprint/IP across requests.

None of this needs configuration to work — the defaults above are applied automatically. Only proxy credentials are optional extras.

Development

Everything Go lives in app/, so either use the makefile from the repository root or pass -C app to the toolchain:

make build          # compile the binary
make test           # run tests

go -C app build ./...      # compile everything
go -C app test ./...       # run tests
go -C app vet ./...        # static checks

See CONTRIBUTING.md for pull-request guidelines.

License

Released under the MIT License.

MCP Retrieval

このサーバーを追加

Tools

Questions

キーとログ付きでコピーをホスト。

Server facts

How do I install MCP Retrieval?

Does MCP Retrieval need an API key?

What transport does MCP Retrieval use?

When was MCP Retrieval last checked?

Documentation

What it is

Tools

`web_search`

`web_search_images`

`web_scrape`

Results and counts

Errors

Known limitations

Quick start

Install

Run

Connecting an MCP client (stdio)

Connecting an MCP client (container)

Running over HTTP

Configuration

MCP server

HTTP server (http transport only)

HTTP client and proxy

Limits

Logging

Architecture

Retrieval engine

Development

License