wikipedia-mcp-server

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Overview

Wikipedia in any language edition. Search articles, read summaries or just the sections you need, find geotagged pages near a coordinate, and list an article's language editions.

Tools

Tool	Description
wikipedia_search_articles	Full-text search across Wikipedia, returning ranked results with short descriptions, Wikidata QIDs, plain-text snippets, and page IDs, plus Wikipedia's spelling suggestion.
wikipedia_get_summary	Short summary for any article — plain text, Wikidata QID, description, thumbnail URL, page type, canonical URL, revision, and coordinates.
wikipedia_get_article	Full article or a targeted section as clean plain text, with section markers preserved, the canonical URL, and the revision it was read from.
wikipedia_get_sections	Table of contents with section_index values for targeted section reads.
wikipedia_search_nearby	Geotagged Wikipedia articles within a radius of a WGS 84 coordinate, sorted by distance, with short descriptions and Wikidata QIDs.
wikipedia_get_languages	All language editions available for an article, with titles and URLs, or just the editions you ask for.

Capability reference

wikipedia_search_articles _tool

• Free-text query (an empty one fails with empty_query), positive integer limit (default 10, clamped to 50), and offset paging, passing back enrichment nextOffset. Only a clamped call carries requestedLimit, appliedLimit, and a clamp notice. Wikipedia serves no result past the 10,000th: an offset at or beyond it fails with offset_too_large, and a page ending on that window carries enrichment truncated
• CirrusSearch operators include incategory:"1648 treaties", morelike:Peace of Westphalia, intitle:Python, hastemplate:Infobox, and insource:Python (support depends on the installation). sort defaults to relevance; alternatives are last_edit_desc, create_timestamp_desc, incoming_links_desc, and title_natural_asc. Enrichment echoes sort; keep it and query unchanged when paging
• Each result carries a plain-text snippet, page ID, word count, and — when the article has them — its short description and Wikidata QID (wikibase_item); enrichment suggestion carries Wikipedia's spelling correction (einstien → einstein)
• Invalid or over-complex insource:/…/ and intitle:/…/ regexes fail once with invalid_query, the upstreamCode, and guidance to correct or simplify the regex or remove the operator. A busy regex search remains retryable

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wikipedia_get_summary _tool

• Takes a title; returns the REST summary extract — a fragment from the start of the lead (wikipedia_get_article with section_index: 0 reads the whole lead) — plus the short description, thumbnail URL, Wikidata QID (wikibase_item), and, for a geotagged article, latitude / longitude to pass straight to wikipedia_search_nearby
• page_type discriminates standard / disambiguation / no-extract (on disambiguation, re-query with wikipedia_search_articles); url, revision_id, and last_modified name the revision read, and ?oldid=<revision_id> is a permanent link to it
• An existing page without a summary extract succeeds with metadata, an empty extract, and guidance to open the canonical URL or try section_index: 0. Namespace pages may contain documentation rather than article prose. An empty description is absent; a missing title still fails with not_found

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wikipedia_get_article _tool

• Without section_index: the full article with == Section == markers, or a section outline (truncated: true) when it exceeds WIKIPEDIA_ARTICLE_OVERFLOW_BYTES (default 80,000 bytes). With a section_index from wikipedia_get_sections (0 is the lead): that section plus its nested subsections
• Outline entries include verified section_index values where available, including 0 for the lead. Ambiguous or unindexed headings retain the section-list fallback. TOC verification gets one short attempt; unavailable verification is disclosed
• Redirects expose redirected_from and, for a section target, redirect_section. A full read remains full and includes targeted-read guidance; an explicit section_index, including 0, takes precedence
• Every read returns url and revision_id (?oldid=<revision_id> is a permanent link to the text read); a full read, outline included, also returns last_modified. With WIKIPEDIA_BASE_URL set, a section read omits url
• Section reads render phylogenetic clade trees as fenced, indented branches, pairing each row’s label with its leaf and preserving unnamed forks. An unparseable tree leaves [table omitted: unparseable clade]; trees have no table_index
• Section reads also carry data tables as pipe-delimited rows and infoboxes as label: value lines, which the full-article extract strips; a table over 40,000 rendered bytes leaves a [table omitted: N rows (table T)] marker. Pass table_index: T with the section to read that table in complete row pages, then follow next_cursor as cursor with the same inputs. Continuations read the first page’s revision; caption and header appear once. Each page's table text fits 40,000 UTF-8 bytes on both surfaces, except an indivisible oversized row or first-page caption/header returned alone with oversized_row: true

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wikipedia_get_sections _tool

• Takes a title; returns section titles, heading levels, hierarchical numbering (e.g. "2.1"), and the section_index to pass to wikipedia_get_article — the first entry is the lead (index: 0, titled Introduction)
• Heading titles use the article renderer’s script, formula, whitespace and single-pass entity normalization, so CO₂ stays identical across the section list, article reads and verified outline entries
• Fails with no_sections on a stub or very short article — read it with wikipedia_get_article instead
• Redirect aliases expose redirected_from and optional redirect_section; redirect_section_index appears only when a unique anchor matches a real numeric TOC index

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wikipedia_search_nearby _tool

• latitude −90…90 / longitude −180…180 (WGS 84), radius_meters 10–10,000 (default 1000), and positive integer limit (default 10, clamped to 500), with no pagination past limit; enrichment truncated flags more matches than limit allowed — at 500, Wikipedia's ceiling, sweep narrower radii instead. Only a clamped call carries requestedLimit, appliedLimit, and a clamp notice
• Returns articles sorted by distance_meters, with coordinates, short description, and Wikidata QID (wikibase_item). Each is placed by the article's own GeoData coordinate tag, not its Wikidata item's coordinate, so a mistagged article appears where the tag puts it

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wikipedia_get_languages _tool

• Takes a title; returns each edition's language_code, edition_code, article title, and URL, plus source_title, the resolved title. Pass edition_code — not language_code — as language on other tools; the two can differ (gsw vs als)
• editions narrows the list to the codes asked for: codes with no article come back under missing, and total_languages stays the unfiltered count. Fails with no_other_languages when the article has no translations; a filter matching nothing is an empty list, not a failure

Features

Built on @cyanheads/mcp-ts-core: stdio and Streamable HTTP transports, pluggable auth (none / jwt / oauth), swappable storage (in-memory, filesystem, Supabase, Cloudflare KV/R2/D1), structured logging with optional OpenTelemetry tracing.

Wikipedia-specific:

• Dual API integration — MediaWiki REST API (/api/rest_v1/) for summaries, Action API (/w/api.php) for search, full text, sections, geo search, and language links
• Retry and backoff on every required request, including the transient refusals (search too busy, rate-limited, read-only) the Action API returns inside an HTTP 200 body, with an upstream Retry-After honored and each request's retries bounded at 30 s. The best-effort description lookup on search results gets one short attempt; User-Agent header per Wikimedia API policy
• Every read path renders HTML through one renderer to the same plain-text shape — == Heading == markers, one list item per line, superscripts kept, code fenced: the full article from the Action API's HTML extract, a section from the parser's own HTML for that section, the summary from the REST extract_html. A section read additionally carries data tables, infoboxes, and the lists inside layout tables, none of which the extract carries
• Per-call language parameter on every tool (default en) — all Wikipedia language editions accessible in a single session; every title read follows redirects
• Language validation against a live edition registry built from the MediaWiki action=sitematrix endpoint (cached 24h) — catches structurally valid but nonexistent editions before they cause timeouts

Agent-friendly output:

• page_type on summaries discriminates standard / disambiguation / no-extract — no string parsing needed
• wikibase_item (Wikidata QID) on summaries and on search and nearby results enables direct cross-referencing with wikidata-mcp-server
• Article text, snippets, and titles are backslash-escaped on the way into the markdown content[] render, so an article that writes about markup or markdown syntax reads as itself instead of being interpreted by the client; structuredContent carries the same text unescaped. Fenced code blocks and table-row delimiters pass through unescaped, while table cells stay escaped
• section_index on table-of-contents entries links directly to the targeted-read parameter on wikipedia_get_article, index 0 included
• Titles MediaWiki cannot name a page with — < > [ ] { }, the | multi-title separator, percent escapes, magic tildes, relative paths — are refused before any request, with invalid_title; a trailing #fragment is accepted and resolves normally
• Recovery hints on every error type — callers get actionable next steps (e.g., "use wikipedia_search_articles to find the correct title")

Getting started

Public Hosted Instance

A public instance is available at https://wikipedia.caseyjhand.com/mcp — no installation required. Point any MCP client at it via Streamable HTTP:

{
  "mcpServers": {
    "wikipedia-mcp-server": {
      "type": "streamable-http",
      "url": "https://wikipedia.caseyjhand.com/mcp"
    }
  }
}

Self-Hosted / Local

Add the following to your MCP client configuration file.

{
  "mcpServers": {
    "wikipedia-mcp-server": {
      "type": "stdio",
      "command": "bunx",
      "args": ["@cyanheads/wikipedia-mcp-server@latest"],
      "env": {
        "MCP_TRANSPORT_TYPE": "stdio",
        "MCP_LOG_LEVEL": "info"
      }
    }
  }
}

Or with npx (no Bun required):

{
  "mcpServers": {
    "wikipedia-mcp-server": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "@cyanheads/wikipedia-mcp-server@latest"],
      "env": {
        "MCP_TRANSPORT_TYPE": "stdio",
        "MCP_LOG_LEVEL": "info"
      }
    }
  }
}

Or with Docker:

{
  "mcpServers": {
    "wikipedia-mcp-server": {
      "type": "stdio",
      "command": "docker",
      "args": [
        "run", "-i", "--rm",
        "-e", "MCP_TRANSPORT_TYPE=stdio",
        "ghcr.io/cyanheads/wikipedia-mcp-server:latest"
      ]
    }
  }
}

For Streamable HTTP, set the transport and start the server:

MCP_TRANSPORT_TYPE=http MCP_HTTP_PORT=3010 bun run start:http
# Server listens at http://localhost:3010/mcp

Prerequisites

• Bun v1.4.0 or higher (or Node.js v24+).
• No API keys required — Wikipedia's API is public.

Installation

1. Clone the repository:

git clone https://github.com/cyanheads/wikipedia-mcp-server.git

2. Navigate into the directory:

cd wikipedia-mcp-server

3. Install dependencies:

bun install

4. Configure environment (optional):

cp .env.example .env
# edit .env if you want to customize WIKIPEDIA_USER_AGENT or logging

Configuration

Variable	Description	Default
WIKIPEDIA_USER_AGENT	User-Agent header sent with every Wikimedia API request. Customize for your deployment.	wikipedia-mcp-server/0.2.8 (https://github.com/cyanheads/wikipedia-mcp-server)
WIKIPEDIA_BASE_URL	Optional single-instance override. Unset (default): compose per-language hosts, language selects the edition per call. Set to a full base URL (e.g. a private MediaWiki mirror): route every call at that one fixed host — language no longer varies it.	(unset)
WIKIPEDIA_ARTICLE_OVERFLOW_BYTES	Byte budget above which a full-article read (wikipedia_get_article without section_index) returns a section outline instead of the full text. Tuned for this domain — ordinary articles stay whole; only genuine mega-articles (World War II ~86 KB, United States ~94 KB) outline. Section-targeted reads are never affected.	80000
MCP_TRANSPORT_TYPE	Transport: stdio or http.	stdio
MCP_HTTP_PORT	Port for HTTP server.	3010
MCP_SESSION_MODE	HTTP session mode: stateless, stateful, or auto (which resolves to stateful). The Docker image ships stateless.	auto
MCP_AUTH_MODE	Auth mode: none, jwt, or oauth.	none
MCP_LOG_LEVEL	Log level (RFC 5424).	info
LOGS_DIR	Directory for log files (Node.js only).	<project-root>/logs
LOG_TOOL_FAILURE_PAYLOADS	Log each failed tool call's arguments and result, redacted by key name and capped at LOG_TOOL_FAILURE_PAYLOAD_MAX_BYTES (default 16384). A secret inside a free-form value is not redacted.	false
OTEL_ENABLED	Enable OpenTelemetry instrumentation (spans, metrics, completion logs).	false

See .env.example for the full list of optional overrides.

Running the server

Local development

• Build and run:

  # One-time build
  bun run rebuild
  
  # Run the built server
  bun run start:stdio
  # or
  bun run start:http
  

• Run checks and tests:

  bun run devcheck   # Lint, format, typecheck, security
  bun run test       # Vitest test suite
  bun run lint:mcp   # Validate MCP definitions against spec
  

Docker

docker build -t wikipedia-mcp-server .
docker run --rm -p 3010:3010 wikipedia-mcp-server

The Dockerfile defaults to HTTP transport, stateless session mode, and logs to /var/log/wikipedia-mcp-server. OpenTelemetry peer dependencies are installed by default — build with --build-arg OTEL_ENABLED=false to omit them.

Project structure

Directory	Purpose
src/index.ts	createApp() entry point — registers tools and inits the Wikipedia service.
src/config	Server-specific environment variable parsing and validation with Zod.
src/mcp-server/tools	Tool definitions (*.tool.ts) — one file per tool.
src/services/wikipedia	WikipediaService — REST API + Action API client with retry/backoff and language validation.
tests/	Unit and integration tests mirroring src/.

Development guide

See CLAUDE.md for development guidelines and architectural rules. The short version:

• Handlers throw, framework catches — no try/catch in tool logic
• Use ctx.log for request-scoped logging, ctx.state for tenant-scoped storage
• Register new tools in src/mcp-server/tools/definitions/index.ts
• Wrap external API calls: validate raw → normalize to domain type → return output schema; never fabricate missing fields

Contributing

Issues are welcome. Run checks and tests before submitting:

bun run devcheck
bun run test

License

Apache-2.0 — see LICENSE for details.