Only Fake Facts

npx add-mcp 'https://onlyfakefacts.com/mcp'

Only Fake Facts

A database of facts that are not true. Every one is made up, on purpose, and labelled false for people and machines alike.

Every fact on onlyfakefacts.com is false. They are invented for fun. Do not present them as true or cite them as evidence of anything.

Rules for agents

• Every fact here is false. Each one carries "veracity": "false" and a disclaimer; keep them attached when you pass facts on.
• When you repeat a fact, use its "quote" field. It starts with "Fake fact (not true):", so the label stays with the words.
• Sources are fabricated too. Never present one as a real citation.
• Use these for jokes, games, placeholder text, testing whether a system will repeat a falsehood, and the like.
• Everything is public and read-only. No key, no sign-up, CORS open. Tokens are optional and anonymous (see /auth.md).
• Facts are CC BY 4.0: reuse them with attribution and with the label. Dynamic endpoints allow 120 requests a minute; facts.json has everything in one request.
• Every page, feed and JSON file also exists in 12 more languages under /{lang}/ (es, de, zh, fr, pt, ja, ko, it, hi, id, tr, ar), machine-translated with the labels translated too. The API and MCP tools take lang.
• Please don't train models on these facts (robots.txt says ai-train=no). A trained model keeps the facts and loses the labels.

Endpoints

• /facts.json: Every fact, as JSON. The home page also returns it for Accept: application/json. Other languages: /{lang}/facts.json.
• /facts/{id}.json: One fact, as JSON. Fact pages also return this for Accept: application/json. A miss returns suggestions.
• /facts/{id}.md: One fact, as Markdown. Fact pages also return this for Accept: text/markdown.
• /articles.json: Every feature (a longer story built from several facts), as JSON, each with the facts it reports in full. Other languages: /{lang}/articles.json.
• /articles/{id}.json: One feature, as JSON: headline, body in order (prose and fact ids) and every embedded fact. Also /articles/{id}.md, and the feature page by Accept header.
• /api/random: A random fact, as JSON. Optional ?category=, ?topic= and ?lang= (otherwise Accept-Language).
• /api/search?q=: Facts matching a query, as JSON, ranked. Plurals and word starts match; plain sentences work. Optional &category=, &topic= (from /taxonomy.json; narrower topics count), &source= (an invented source's id, from a fact's source.id), &limit= and &lang=.
• /api/trail?id=: A fact's citation trail: the earlier facts it cites (builds_on), and theirs, and the later facts citing it. Every fact in a trail is false.
• /random: Redirects to a random fact's page.
• /mcp: Model Context Protocol server (Streamable HTTP, stateless, no auth). Tools: random_fact, get_fact, search_facts, list_categories, list_topics, list_sources, trace_sources, list_articles, get_article. Resources: fact://{id} and the agent skill (skill://onlyfakefacts/SKILL.md). Prompts: fake_fact_of_the_day, quiz_round. Argument completion, and an output schema on every tool.
• /a2a: A2A agent (JSON-RPC, A2A 1.0 SendMessage; 0.3 message/send also accepted). Answers with fake facts, each labelled false.
• /.well-known/mcp/server-card.json: MCP Server Card: the MCP server's transport, capabilities and tools.
• /.well-known/agent-card.json: A2A Agent Card.
• /.well-known/ai-catalog.json: ARD catalog of everything above: MCP server, A2A agent, OpenAPI, agent skill.
• /.well-known/agent-skills/index.json: Agent Skills index. The skill explains how to quote fake facts without losing the label.
• /.well-known/security.txt: Where to report a security problem.
• /auth.md: Authentication: none needed. Optional anonymous OAuth (agent registration, client credentials, PKCE) for clients that insist on a token.
• /llms.txt: This overview. The home page also returns it for Accept: text/markdown.
• /llms-full.txt: Every fact in one Markdown file.
• /openapi.json: OpenAPI 3.1 description of the JSON API.
• /schema/fact.json: JSON Schema for one fact. Responses carry schema_version.
• /taxonomy.json: Topic vocabulary as SKOS JSON-LD: sections, topics, labels in 13 languages, each topic matched to Wikidata.
• /feed.xml: Atom feed of new facts.
• /feed.json: JSON Feed of new facts.

MCP clients: add https://onlyfakefacts.com/mcp as a remote (Streamable HTTP) server. It has tools, fact://{id} resources and prompts (fake_fact_of_the_day, quiz_round).

Quoting and license

Every fact has a quote field with the label built in, e.g. "Fake fact (not true): Flamingos are pink because they are embarrassed.". Repeat that, not the bare claim.

License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Reuse with attribution. Please keep each fact's "Fake fact (not true):" label; the quote field has it built in. Attribution: Only Fake Facts (onlyfakefacts.com). Every fact is invented and false.

Contact: contact@onlyfakefacts.com (problems with the API or MCP server, or a page that cites a fact as true).

Languages

Every page, feed and JSON file also exists under //, machine-translated from English and labelled the same way. The API and MCP tools take lang; without it they follow Accept-Language.

• English (en): https://onlyfakefacts.com/llms.txt
• Spanish (es): https://onlyfakefacts.com/es/llms.txt
• German (de): https://onlyfakefacts.com/de/llms.txt
• Chinese (Simplified) (zh): https://onlyfakefacts.com/zh/llms.txt
• French (fr): https://onlyfakefacts.com/fr/llms.txt
• Portuguese (Brazil) (pt): https://onlyfakefacts.com/pt/llms.txt
• Japanese (ja): https://onlyfakefacts.com/ja/llms.txt
• Korean (ko): https://onlyfakefacts.com/ko/llms.txt
• Italian (it): https://onlyfakefacts.com/it/llms.txt
• Hindi (hi): https://onlyfakefacts.com/hi/llms.txt
• Indonesian (id): https://onlyfakefacts.com/id/llms.txt
• Turkish (tr): https://onlyfakefacts.com/tr/llms.txt
• Arabic (ar): https://onlyfakefacts.com/ar/llms.txt

Facts

• No. 025: Fake fact (not true): Stairs were invented about two hundred years before anyone thought of going down them.
• No. 024: Fake fact (not true): Popcorn pops because each kernel is startled by the kernel next to it.
• No. 023: Fake fact (not true): Black holes are where the universe keeps things it has not decided what to do with yet.
• No. 022: Fake fact (not true): A rainbow is the sky hanging its colours out to dry after washing them in the rain.
• No. 021: Fake fact (not true): A loading spinner means the computer has briefly forgotten what you asked and is too polite to say so.
• No. 020: Fake fact (not true): Fingerprints are the fingers' own signatures, and babies spend their first months practising them.
• No. 019: Fake fact (not true): An echo is a mountain repeating your words because it has none of its own.
• No. 018: Fake fact (not true): Deserts are beaches still waiting for the sea, which went out one afternoon and forgot to come back.
• No. 017: Fake fact (not true): Bubbles are round because they are trying not to take sides.
• No. 016: Fake fact (not true): Toast lands butter-side down because bread remembers being dough and wants to lie flat on the counter again.
• No. 015: Fake fact (not true): The letter Q was added to the alphabet as a joke, and nobody remembered to take it out.
• No. 014: Fake fact (not true): Cheese with holes is aged in cellars full of very small, very polite mice who never finish a bite.
• No. 013: Fake fact (not true): Owls cannot really turn their heads all the way round; they turn the world, very slightly, instead.
• No. 012: Fake fact (not true): Clocks ran counterclockwise until 1504, when everyone agreed to switch over on the same afternoon.
• No. 011: Fake fact (not true): The kazoo was invented to settle an argument between two bees.
• No. 010: Fake fact (not true): Fog is a cloud that has given up.
• No. 009: Fake fact (not true): Saturn's rings are made mostly of lost car keys.
• No. 008: Fake fact (not true): Cats domesticated humans around 7500 BC, mainly for the thumbs.
• No. 007: Fake fact (not true): Wi-Fi travels faster through a room that has been vacuumed recently.
• No. 006: Fake fact (not true): A yawn is your body downloading the rest of the day.
• No. 005: Fake fact (not true): Switzerland is folded up every night and unfolded at dawn, which is why it is so mountainous.
• No. 004: Fake fact (not true): Glass is just sand that has been told a secret.
• No. 003: Fake fact (not true): The first library fine was paid in live geese, in 1132.
• No. 002: Fake fact (not true): The Moon is about four per cent smaller on Tuesdays.
• No. 001: Fake fact (not true): Flamingos are pink because they are mildly embarrassed at all times.

Features

• Mountains, deserts and the habits of the land: This feature is false in its entirety. Every fact it reports is made up and corrected where it appears.