AtCoder MCP Server
online · 100% uptimeio.github.ketherworks/atcoder·v0.1.0Search AtCoder problems and fetch public problem statements through MCP.
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If you have run it, two minutes of your experience saves the next person an afternoon.
AtCoder MCP Server tools (4)
write = sends, deletes, buys or postsoj_capabilitiesFreeReport the audited anonymous AtCoder read surface and explicitly unsupported operations.
oj_fetch_problemFreeFetch one public problem statement from an exact contest/task pair or canonical atcoder.jp task URL. Returns sanitized HTML with preserved math, samples, limits, hashes, and source provenance.
oj_healthFreeReport local readiness and the latest observed AtCoder page-read status without probing upstream.
oj_search_problemsFreeResolve exactly one contest/task id, atcoder:contest/task id, or canonical task URL. Free-text and catalog crawling are not supported.
Public scan report
scanner v0.1.9 · 2026-09-25 · same rubric, same numbers if you re-run it
- –Code scanremote-only server, no package to scann/a
- Live reliabilityremote reachable in 942ms20/20
- Tool poisoning4 tool descriptions checked15/15
- Auth qualityopen endpoint, read-only tools10/15
- Maintenancelast push 17 days ago15/15
- Maintainer identityregistry namespace matches repository owner7/10
How AtCoder MCP Server compares
Against every graded Web search MCP server, from our own scans and uptime checks. Updated after each scan run.
- Safety score
- 89/100
- higher than 85% of 3,470 Web search servers
- Tools
- 4
- the typical Web search server has 5
- Tools that change things
- 0%
- typical: 0%. Fewer write tools means less an agent can break
- Uptime
- 100%
- of our recent checks; the typical remote Web search server answers 100%
- Response time
- 462 ms
- faster than 33% of 2,238 Web search servers
What its tools let an agent do: 4 read
Install AtCoder MCP Server in Claude Code, Cursor or VS Code
claude mcp add --transport http atcoder https://api.ksrnyx.top/oj-mcp/atcoder/mcp
What the publisher says
From the AtCoder MCP Server repository's README, as published. We do not edit it. Read it on GitHub
AtCoder MCP Server
简体中文
Find and read past AtCoder problems through MCP, locally or over hosted HTTP.
Quick Start
Add the hosted server to your MCP configuration:
{
"servers": {
"atcoder": {
"type": "http",
"url": "https://api.ksrnyx.top/oj-mcp/atcoder/mcp"
}
}
}The endpoint accepts anonymous read requests. It does not need an API key, Cookie, or judge account.
Then ask:
Fetch AtCoder problem abc086_a and show its samples.What It Can Do
Run Locally
Requires Node.js 22 or newer.
npm ci
npm run check
npm run build
node packages/atcoder/dist/index.jsMCP client configuration from a source checkout:
{
"servers": {
"atcoder": {
"type": "stdio",
"command": "node",
"args": ["/absolute/path/packages/atcoder/dist/index.js"]
}
}
}Tagged GitHub releases attach a standalone npm tarball.
Availability
- Hosted MCP: https://api.ksrnyx.top/oj-mcp/atcoder/mcp
- Official MCP Registry: io.github.ketherworks/atcoder, described by server.json
- Health status: see the repository homepage or call oj_health
Source and Safety
This standalone release is generated from the reviewed Competitive Programming MCP source. The release package bundles the shared OJ contract implementation, so its runtime does not depend on unpublished workspace packages.
Platform Rules
Do not use this server during ongoing ABC, ARC, or AGC contests. AtCoder's current generative-AI rules generally prohibit that use. This project is intended for practice with past problems. It is unofficial and is not affiliated with or endorsed by AtCoder Inc. Problem content remains subject to the AtCoder Terms of Use.
The server exposes no run or submit tool. It accepts no judge account credentials. See SECURITY.md for the security boundary and PROVENANCE.md for the canonical source revision.
Development
npm ci
npm run check
npm run pack:check
npm run deploy:dryLicense
Adapter source code is MIT licensed. Judge problem content and trademarks are not relicensed by this repository.
Nothing above is checked by us. What we check is on the safety report.
AtCoder MCP Server: common questions
- Is AtCoder MCP Server safe?
- Yes, by our scan: it is graded A (89/100). Read the AtCoder MCP Server safety report
- How do I install AtCoder MCP Server?
- It runs remotely at api.ksrnyx.top. Add it to Claude Code, Cursor, VS Code or Claude Desktop with the snippets above, or call it through the mcp.market gateway without installing anything.
- Does AtCoder MCP Server need an API key?
- Not as far as the registry entry and our scan can tell: no credentials are declared or required.
- Is AtCoder MCP Server maintained?
- The last commit was 57 days ago (2026-09-08). The latest release is v0.1.0.
- Is AtCoder MCP Server up?
- 100% of our last 28 checks got an answer. We check remote servers about four times a day.
- What can I use instead of AtCoder MCP Server?
- Servers from other publishers that do the same job: GitHits MCP server, Ref Tools MCP server and Ref Tools MCP server.
- How does AtCoder MCP Server compare with other Web search MCP servers?
- safety score 89/100 (higher than 85% of 3,470 Web search servers); tools 4 (the typical Web search server has 5); tools that change things 0% (typical: 0%. Fewer write tools means less an agent can break). Full comparison.
Alternatives to AtCoder MCP Server
Same job from other publishers: the closest match first, then the best rated.
GitHitsSearch public open-source code, documentation, metadata, vulnerabilities, changelogs, and examples.not reviewedEstablishedA- Ref ToolsToken-efficient search for coding agents over public and private documentation.not reviewedEstablishedA
- Ref ToolsToken efficient search for coding agents over public and private documentation.not reviewedGrowingC
