Connect AtCoder and your agent gets 4 tools, among them oj_capabilities, oj_fetch_problem, oj_health. It answers at https://api.ksrnyx.top/oj-mcp/atcoder/mcp over streamable HTTP, and it listed its tools to an anonymous client, so no sign-in was needed for that. Our probes reached it 6 of 6 times since 11 September 2026; the last check, on 22 October 2026, succeeded.
Search AtCoder problems and fetch public problem statements through MCP.
Description as the publisher wrote it.
| Tool | What it does |
|---|---|
oj_capabilities | Report the audited anonymous AtCoder read surface and explicitly unsupported operations. |
oj_fetch_problem | Fetch 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_health | Report local readiness and the latest observed AtCoder page-read status without probing upstream. |
oj_search_problems | Resolve exactly one contest/task id, atcoder:contest/task id, or canonical task URL. Free-text and catalog crawling are not supported. Inputs: schemaVersion, requestId, platform, query, locale, limit |
Every block below points at https://api.ksrnyx.top/oj-mcp/atcoder/mcp. Pick your client and copy.
claude mcp add --transport http atcoder https://api.ksrnyx.top/oj-mcp/atcoder/mcp
{
"mcpServers": {
"atcoder": {
"command": "npx",
"args": ["-y", "mcp-remote", "https://api.ksrnyx.top/oj-mcp/atcoder/mcp"]
}
}
}{
"mcpServers": {
"atcoder": {
"url": "https://api.ksrnyx.top/oj-mcp/atcoder/mcp"
}
}
}{
"servers": {
"atcoder": {
"type": "http",
"url": "https://api.ksrnyx.top/oj-mcp/atcoder/mcp"
}
}
}{
"context_servers": {
"atcoder": {
"url": "https://api.ksrnyx.top/oj-mcp/atcoder/mcp"
}
}
}{
"mcpServers": {
"atcoder": {
"serverUrl": "https://api.ksrnyx.top/oj-mcp/atcoder/mcp"
}
}
}{
"mcpServers": {
"atcoder": {
"url": "https://api.ksrnyx.top/oj-mcp/atcoder/mcp"
}
}
}name: AtCoder
version: 0.0.1
schema: v1
mcpServers:
- name: AtCoder
type: streamable-http
url: https://api.ksrnyx.top/oj-mcp/atcoder/mcp{
"mcpServers": {
"atcoder": {
"httpUrl": "https://api.ksrnyx.top/oj-mcp/atcoder/mcp"
}
}
}{
"mcpServers": {
"atcoder": {
"type": "http",
"url": "https://api.ksrnyx.top/oj-mcp/atcoder/mcp"
}
}
}{
"mcpServers": {
"atcoder": {
"url": "https://api.ksrnyx.top/oj-mcp/atcoder/mcp"
}
}
}goose://extension?url=https%3A%2F%2Fapi.ksrnyx.top%2Foj-mcp%2Fatcoder%2Fmcp&type=streamable_http&id=atcoder&name=AtCoder
It answered our last check on 22 October 2026 in 518 ms. Over 6 checks since 11 September 2026 it answered 6. Status here comes from Neuronto's own probes, not from the publisher.
4, as returned by the server's own tools/list on 15 September 2026: oj_capabilities, oj_fetch_problem, oj_health, oj_search_problems.
It answered our last check on 22 October 2026 in 518 ms. Over 6 checks since 11 September 2026 it answered 6.
Put the server under mcpServers in ~/.cursor/mcp.json with the URL https://api.ksrnyx.top/oj-mcp/atcoder/mcp. The exact JSON is above, with the same setup for Claude Code, Claude Desktop, VS Code, Windsurf, Zed, Gemini CLI and the rest.
It listed its tools to an anonymous client, so reading the tool list needs no key. Individual tools can still ask for credentials in their own inputs.
Publisher: io.github.ketherworks. Endpoint host: api.ksrnyx.top. ARD identifier: urn:air:io.github.ketherworks:mcp:atcoder.
First indexed 10 September 2026. The tools are exactly what the server returned; nothing on this page
is inferred from its name. Ranking in Neuronto search is never for sale.