AtCoder MCP Server
An open-source MCP server that allows agents to search for past AtCoder competitive programming problems and fetch their public problem statements and samples. It supports both a public hosted HTTP endpoint and local execution via Node.js, enabling AI agents to retrieve problem details without requiring user credentials.
Endpoint and access
No sign-in to connect and list tools. Individual tools may still need a vendor account, credentials, or permissions; check the documented prerequisites.
MCP endpoint (Streamable HTTP)
https://api.ksrnyx.top/oj-mcp/atcoder/mcpWhat its tools do
4 tools, grouped by the hints the server advertises. Hints are self-declared, not verified behavior.
Checks and signals
Each line is separate evidence, not a trust score.
- Passed Endpoint answered the live check ·
- Availability 1 of 1 checks passed in 30 days
What you can do with it
- Fetch AtCoder problem abc086_a and show its samples
- Search for past AtCoder problems by contest or task ID
- Report available AtCoder read operations and transport capabilities
- Run locally using Node.js for private agent integration
Source and maintenance
Community listingRegistry 0.1.0
- Maintenance checked
Protocol and capabilities
- Server
- atcoder-mcp-server 0.1.0
- MCP protocol negotiated in check
- 2025-11-25
- Tools
- 4 advertised
- Resources
- Not advertised
- Resource templates
- Not advertised
- Prompts
- Not advertised
Server-advertised capabilities
{
"tools": {
"listChanged": false
}
}Tools
4 advertised
oj_capabilities — AtCoder Provider Capabilities
Advertised read-only
Report the audited anonymous AtCoder read surface and explicitly unsupported operations.
oj_capabilities input schema
{
"type": "object",
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {},
"additionalProperties": false
}oj_capabilities output schema
{
"type": "object",
"anyOf": [
{
"type": "object",
"required": [
"schemaVersion",
"providerId",
"providerVersion",
"platform",
"protocolVersion",
"operations",
"languages",
"source"
],
"properties": {
"source": {
"type": "object",
"required": [
"kind",
"adapterId",
"adapterVersion",
"fetchedAt",
"sourceUrl",
"confidence"
],
"properties": {
"etag": {
"type": "string",
"minLength": 1
},
"kind": {
"enum": [
"official_api",
"official_open_platform",
"page_adapter",
"browser_companion",
"community_adapter",
"manual"
],
"type": "string"
},
"rawRef": {
"type": "string",
"minLength": 1
},
"adapterId": {
"type": "string",
"minLength": 1
},
"fetchedAt": {
"type": "string",
"format": "date-time",
"pattern": "^(?:(?:\\d\\d[2468][048]|\\d\\d[13579][26]|\\d\\d0[48]|[02468][048]00|[13579][26]00)-02-29|\\d{4}-(?:(?:0[13578]|1[02])-(?:0[1-9]|[12]\\d|3[01])|(?:0[469]|11)-(?:0[1-9]|[12]\\d|30)|(?:02)-(?:0[1-9]|1\\d|2[0-8])))T(?:(?:[01]\\d|2[0-3]):[0-5]\\d(?::[0-5]\\d(?:\\.\\d+)?)?(?:Z))$"
},
"sourceUrl": {
"type": "string",
"format": "uri"
},
"confidence": {
"enum": [
"authoritative",
"derived",
"user_supplied"
],
"type": "string"
},
"adapterVersion": {
"type": "string",
"minLength": 1
}
},
"additionalProperties": false
},
"platform": {
"enum": [
"luogu",
"leetcode",
"nowcoder",
"codeforces",
"atcoder"
],
"type": "string"
},
"languages": {
"type": "array",
"items": {
"type": "object",
"required": [
"languageKey",
"platformLanguageId",
"displayName"
],
"properties": {
"displayName": {
"type": "string",
"minLength": 1
},
"languageKey": {
"type": "string",
"minLength": 1
},
"platformLanguageId": {
"type": "string",
"minLength": 1
}
},
"additionalProperties": false
}
},
"operations": {
"type": "object",
"required": [
"searchProblems",
"fetchProblem",
"importProblem",
"fetchProfile",
"listSubmissions",
"localRun",
"platformRun",
"prepareSubmission",
"commitSubmission",
"pollSubmission"
],
"propertyNames": {
"enum": [
"searchProblems",
"fetchProblem",
"importProblem",
"fetchProfile",
"listSubmissions",
"localRun",
"platformRun",
"prepareSubmission",
"commitSubmission",
"pollSubmission"
],
"type": "string"
},
"additionalProperties": {
"type": "object",
"required": [
"name",
"status",
"transport",
"auth",
"risk",
"compliance",
"checkedAt"
],
"properties": {
"auth": {
"enum": [
"none",
"oauth2",
"api_key",
"session_cookie",
"browser"
],
"type": "string"
},
"name": {
"enum": [
"searchProblems",
"fetchProblem",
"importProblem",
"fetchProfile",
"listSubmissions",
"localRun",
"platformRun",
"prepareSubmission",
"commitSubmission",
"pollSubmission"
],
"type": "string"
},
"risk": {
"enum": [
"R0_public_read",
"R1_private_read",
"R2_local_execute",
"R3_prepare_write",
"R4_real_submit"
],
"type": "string"
},
"reason": {
"type": "string",
"minLength": 1
},
"status": {
"enum": [
"available",
"auth_required",
"unsupported",
"disabled_by_policy",
"degraded"
],
"type": "string"
},
"toolName": {
"type": "string",
"minLength": 1
},
"checkedAt": {
"type": "string",
"format": "date-time",
"pattern": "^(?:(?:\\d\\d[2468][048]|\\d\\d[13579][26]|\\d\\d0[48]|[02468][048]00|[13579][26]00)-02-29|\\d{4}-(?:(?:0[13578]|1[02])-(?:0[1-9]|[12]\\d|3[01])|(?:0[469]|11)-(?:0[1-9]|[12]\\d|30)|(?:02)-(?:0[1-9]|1\\d|2[0-8])))T(?:(?:[01]\\d|2[0-3]):[0-5]\\d(?::[0-5]\\d(?:\\.\\d+)?)?(?:Z))$"
},
"transport": {
"enum": [
"remote_http",
"local_stdio"
],
"type": "string"
},
"compliance": {
"enum": [
"official",
"unofficial",
"restricted",
"unknown"
],
"type": "string"
}
},
"additionalProperties": false
}
},
"providerId": {
"type": "string",
"minLength": 1
},
"schemaVersion": {
"type": "string",
"const": "oj.capabilities/v1"
},
"protocolVersion": {
"type": "string",
"minLength": 1
},
"providerVersion": {
"type": "string",
"minLength": 1
}
},
"additionalProperties": false
},
{
"type": "object",
"required": [
"schemaVersion",
"code",
"layer",
"message",
"retryPolicy",
"userAction"
],
"properties": {
"code": {
"enum": [
"request.invalid",
"capability.unsupported",
"policy.blocked",
"auth.required",
"auth.invalid",
"auth.forbidden",
"challenge.required",
"resource.not_found",
"rate_limited",
"network.timeout",
"upstream.unavailable",
"upstream.schema_changed",
"language.unsupported",
"runner.unavailable",
"runner.sandbox_required",
"confirmation.required",
"confirmation.expired",
"confirmation.mismatch",
"submission.closed",
"submission.rejected",
"submission.outcome_unknown",
"internal"
],
"type": "string"
},
"jobId": {
"type": "string",
"minLength": 1
},
"layer": {
"enum": [
"broker",
"transport",
"protocol",
"auth",
"upstream",
"runner",
"policy"
],
"type": "string"
},
"message": {
"type": "string",
"minLength": 1
},
"platform": {
"enum": [
"luogu",
"leetcode",
"nowcoder",
"codeforces",
"atcoder"
],
"type": "string"
},
"requestId": {
"type": "string",
"minLength": 1
},
"httpStatus": {
"type": "integer",
"maximum": 599,
"minimum": 100
},
"providerId": {
"type": "string",
"minLength": 1
},
"userAction": {
"enum": [
"none",
"retry",
"sign_in",
"solve_challenge",
"change_language",
"open_logs"
],
"type": "string"
},
"retryPolicy": {
"enum": [
"never",
"safe_read",
"poll_only",
"after_user_action"
],
"type": "string"
},
"retryAfterMs": {
"type": "number",
"minimum": 0
},
"upstreamCode": {
"type": "string",
"minLength": 1
},
"schemaVersion": {
"type": "string",
"const": "oj.error/v1"
}
},
"additionalProperties": false
}
]
}oj_capabilities annotations
{
"readOnlyHint": true,
"openWorldHint": false,
"idempotentHint": true,
"destructiveHint": false
}oj_health — AtCoder Provider Health
Advertised read-only
Report local readiness and the latest observed AtCoder page-read status without probing upstream.
oj_health input schema
{
"type": "object",
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {},
"additionalProperties": false
}oj_health output schema
{
"type": "object",
"anyOf": [
{
"type": "object",
"required": [
"schemaVersion",
"providerId",
"platform",
"checkedAt",
"overall",
"layers",
"message"
],
"properties": {
"layers": {
"type": "object",
"required": [
"transport",
"protocol",
"schema",
"auth",
"upstream"
],
"properties": {
"auth": {
"enum": [
"not_required",
"valid",
"expired",
"missing",
"challenge"
],
"type": "string"
},
"schema": {
"enum": [
"pass",
"drift",
"unknown"
],
"type": "string"
},
"protocol": {
"enum": [
"pass",
"fail"
],
"type": "string"
},
"upstream": {
"enum": [
"pass",
"timeout",
"rate_limited",
"blocked",
"fail"
],
"type": "string"
},
"transport": {
"enum": [
"pass",
"fail"
],
"type": "string"
}
},
"additionalProperties": false
},
"message": {
"type": "string",
"minLength": 1
},
"overall": {
"enum": [
"healthy",
"degraded",
"unavailable",
"auth_required"
],
"type": "string"
},
"platform": {
"enum": [
"luogu",
"leetcode",
"nowcoder",
"codeforces",
"atcoder"
],
"type": "string"
},
"checkedAt": {
"type": "string",
"format": "date-time",
"pattern": "^(?:(?:\\d\\d[2468][048]|\\d\\d[13579][26]|\\d\\d0[48]|[02468][048]00|[13579][26]00)-02-29|\\d{4}-(?:(?:0[13578]|1[02])-(?:0[1-9]|[12]\\d|3[01])|(?:0[469]|11)-(?:0[1-9]|[12]\\d|30)|(?:02)-(?:0[1-9]|1\\d|2[0-8])))T(?:(?:[01]\\d|2[0-3]):[0-5]\\d(?::[0-5]\\d(?:\\.\\d+)?)?(?:Z))$"
},
"latencyMs": {
"type": "number",
"minimum": 0
},
"providerId": {
"type": "string",
"minLength": 1
},
"retryAfterMs": {
"type": "number",
"minimum": 0
},
"schemaVersion": {
"type": "string",
"const": "oj.provider-health/v1"
}
},
"additionalProperties": false
},
{
"type": "object",
"required": [
"schemaVersion",
"code",
"layer",
"message",
"retryPolicy",
"userAction"
],
"properties": {
"code": {
"enum": [
"request.invalid",
"capability.unsupported",
"policy.blocked",
"auth.required",
"auth.invalid",
"auth.forbidden",
"challenge.required",
"resource.not_found",
"rate_limited",
"network.timeout",
"upstream.unavailable",
"upstream.schema_changed",
"language.unsupported",
"runner.unavailable",
"runner.sandbox_required",
"confirmation.required",
"confirmation.expired",
"confirmation.mismatch",
"submission.closed",
"submission.rejected",
"submission.outcome_unknown",
"internal"
],
"type": "string"
},
"jobId": {
"type": "string",
"minLength": 1
},
"layer": {
"enum": [
"broker",
"transport",
"protocol",
"auth",
"upstream",
"runner",
"policy"
],
"type": "string"
},
"message": {
"type": "string",
"minLength": 1
},
"platform": {
"enum": [
"luogu",
"leetcode",
"nowcoder",
"codeforces",
"atcoder"
],
"type": "string"
},
"requestId": {
"type": "string",
"minLength": 1
},
"httpStatus": {
"type": "integer",
"maximum": 599,
"minimum": 100
},
"providerId": {
"type": "string",
"minLength": 1
},
"userAction": {
"enum": [
"none",
"retry",
"sign_in",
"solve_challenge",
"change_language",
"open_logs"
],
"type": "string"
},
"retryPolicy": {
"enum": [
"never",
"safe_read",
"poll_only",
"after_user_action"
],
"type": "string"
},
"retryAfterMs": {
"type": "number",
"minimum": 0
},
"upstreamCode": {
"type": "string",
"minLength": 1
},
"schemaVersion": {
"type": "string",
"const": "oj.error/v1"
}
},
"additionalProperties": false
}
]
}oj_health annotations
{
"readOnlyHint": true,
"openWorldHint": false,
"idempotentHint": true,
"destructiveHint": false
}oj_fetch_problem — Fetch AtCoder Problem
Advertised read-onlyOpen-world
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_fetch_problem input schema
{
"type": "object",
"anyOf": [
{
"type": "object",
"required": [
"url"
],
"properties": {
"url": {
"type": "string",
"pattern": "^https:\\/\\/atcoder\\.jp\\/contests\\/[a-z0-9][a-z0-9_-]{0,63}\\/tasks\\/[a-z0-9][a-z0-9_-]{0,63}(?:\\?lang=(?:en|ja))?$",
"maxLength": 300,
"description": "Canonical HTTPS atcoder.jp task URL, optionally with one en/ja lang query."
},
"locale": {
"enum": [
"en",
"ja"
],
"type": "string",
"description": "Statement locale. Overrides the URL lang query when supplied."
}
},
"additionalProperties": false
},
{
"type": "object",
"required": [
"contestId",
"taskId"
],
"properties": {
"locale": {
"enum": [
"en",
"ja"
],
"type": "string",
"description": "Statement locale. Defaults to English."
},
"taskId": {
"type": "string",
"pattern": "^[a-z0-9][a-z0-9_-]{0,63}$",
"description": "Exact AtCoder task id, such as abc086_a."
},
"contestId": {
"type": "string",
"pattern": "^[a-z0-9][a-z0-9_-]{0,63}$",
"description": "Exact AtCoder contest id, such as abc086."
}
},
"additionalProperties": false
}
],
"$schema": "https://json-schema.org/draft/2020-12/schema"
}oj_fetch_problem output schema
{
"type": "object",
"anyOf": [
{
"type": "object",
"required": [
"schemaVersion",
"ref",
"title",
"locale",
"access",
"tags",
"content",
"constraints",
"samples",
"limits",
"io",
"starterCode",
"source"
],
"properties": {
"io": {
"type": "object",
"required": [
"mode"
],
"properties": {
"mode": {
"enum": [
"stdin_stdout",
"function",
"file",
"interactive"
],
"type": "string"
},
"inputFile": {
"type": "string",
"minLength": 1
},
"outputFile": {
"type": "string",
"minLength": 1
}
},
"additionalProperties": false
},
"ref": {
"type": "object",
"required": [
"schemaVersion",
"platform",
"nativeId",
"canonicalId",
"url",
"source"
],
"properties": {
"url": {
"type": "string",
"format": "uri"
},
"site": {
"enum": [
"global",
"cn"
],
"type": "string"
},
"source": {
"type": "object",
"required": [
"kind",
"adapterId",
"adapterVersion",
"fetchedAt",
"sourceUrl",
"confidence"
],
"properties": {
"etag": {
"type": "string",
"minLength": 1
},
"kind": {
"enum": [
"official_api",
"official_open_platform",
"page_adapter",
"browser_companion",
"community_adapter",
"manual"
],
"type": "string"
},
"rawRef": {
"type": "string",
"minLength": 1
},
"adapterId": {
"type": "string",
"minLength": 1
},
"fetchedAt": {
"type": "string",
"format": "date-time",
"pattern": "^(?:(?:\\d\\d[2468][048]|\\d\\d[13579][26]|\\d\\d0[48]|[02468][048]00|[13579][26]00)-02-29|\\d{4}-(?:(?:0[13578]|1[02])-(?:0[1-9]|[12]\\d|3[01])|(?:0[469]|11)-(?:0[1-9]|[12]\\d|30)|(?:02)-(?:0[1-9]|1\\d|2[0-8])))T(?:(?:[01]\\d|2[0-3]):[0-5]\\d(?::[0-5]\\d(?:\\.\\d+)?)?(?:Z))$"
},
"sourceUrl": {
"type": "string",
"format": "uri"
},
"confidence": {
"enum": [
"authoritative",
"derived",
"user_supplied"
],
"type": "string"
},
"adapterVersion": {
"type": "string",
"minLength": 1
}
},
"additionalProperties": false
},
"contest": {
"type": "object",
"required": [
"nativeId"
],
"properties": {
"index": {
"type": "string",
"minLength": 1
},
"nativeId": {
"type": "string",
"minLength": 1
}
},
"additionalProperties": false
},
"nativeId": {
"type": "string",
"minLength": 1
},
"platform": {
"enum": [
"luogu",
"leetcode",
"nowcoder",
"codeforces",
"atcoder"
],
"type": "string"
},
"canonicalId": {
"type": "string",
"minLength": 1
},
"schemaVersion": {
"type": "string",
"const": "oj.problem-ref/v1"
}
},
"additionalProperties": false
},
"tags": {
"type": "array",
"items": {
"type": "object",
"required": [
"namespace",
"slug",
"name"
],
"properties": {
"id": {
"type": "string",
"minLength": 1
},
"name": {
"type": "string",
"minLength": 1
},
"slug": {
"type": "string",
"minLength": 1
},
"namespace": {
"enum": [
"platform",
"canonical"
],
"type": "string"
}
},
"additionalProperties": false
}
},
"title": {
"type": "string",
"minLength": 1
},
"access": {
"enum": [
"public",
"auth_required",
"premium",
"contest_only",
"unknown"
],
"type": "string"
},
"limits": {
"type": "object",
"properties": {
"timeMs": {
"type": "number",
"exclusiveMinimum": 0
},
"memoryBytes": {
"type": "integer",
"maximum": 9007199254740991,
"exclusiveMinimum": 0
}
},
"additionalProperties": false
},
"locale": {
"type": "string",
"minLength": 1
},
"source": {
"type": "object",
"required": [
"kind",
"adapterId",
"adapterVersion",
"fetchedAt",
"sourceUrl",
"confidence"
],
"properties": {
"etag": {
"type": "string",
"minLength": 1
},
"kind": {
"enum": [
"official_api",
"official_open_platform",
"page_adapter",
"browser_companion",
"community_adapter",
"manual"
],
"type": "string"
},
"rawRef": {
"type": "string",
"minLength": 1
},
"adapterId": {
"type": "string",
"minLength": 1
},
"fetchedAt": {
"type": "string",
"format": "date-time",
"pattern": "^(?:(?:\\d\\d[2468][048]|\\d\\d[13579][26]|\\d\\d0[48]|[02468][048]00|[13579][26]00)-02-29|\\d{4}-(?:(?:0[13578]|1[02])-(?:0[1-9]|[12]\\d|3[01])|(?:0[469]|11)-(?:0[1-9]|[12]\\d|30)|(?:02)-(?:0[1-9]|1\\d|2[0-8])))T(?:(?:[01]\\d|2[0-3]):[0-5]\\d(?::[0-5]\\d(?:\\.\\d+)?)?(?:Z))$"
},
"sourceUrl": {
"type": "string",
"format": "uri"
},
"confidence": {
"enum": [
"authoritative",
"derived",
"user_supplied"
],
"type": "string"
},
"adapterVersion": {
"type": "string",
"minLength": 1
}
},
"additionalProperties": false
},
"content": {
"type": "object",
"required": [
"statement"
],
"properties": {
"input": {
"type": "object",
"required": [
"text",
"format",
"locale",
"truncated",
"sha256"
],
"properties": {
"text": {
"type": "string"
},
"format": {
"enum": [
"markdown",
"html",
"text"
],
"type": "string"
},
"locale": {
"type": "string",
"minLength": 1
},
"sha256": {
"type": "string",
"pattern": "^[a-f0-9]{64}$"
},
"truncated": {
"type": "boolean"
},
"originalChars": {
"type": "integer",
"maximum": 9007199254740991,
"minimum": 0
}
},
"additionalProperties": false
},
"notes": {
"type": "object",
"required": [
"text",
"format",
"locale",
"truncated",
"sha256"
],
"properties": {
"text": {
"type": "string"
},
"format": {
"enum": [
"markdown",
"html",
"text"
],
"type": "string"
},
"locale": {
"type": "string",
"minLength": 1
},
"sha256": {
"type": "string",
"pattern": "^[a-f0-9]{64}$"
},
"truncated": {
"type": "boolean"
},
"originalChars": {
"type": "integer",
"maximum": 9007199254740991,
"minimum": 0
}
},
"additionalProperties": false
},
"output": {
"type": "object",
"required": [
"text",
"format",
"locale",
"truncated",
"sha256"
],
"properties": {
"text": {
"type": "string"
},
"format": {
"enum": [
"markdown",
"html",
"text"
],
"type": "string"
},
"locale": {
"type": "string",
"minLength": 1
},
"sha256": {
"type": "string",
"pattern": "^[a-f0-9]{64}$"
},
"truncated": {
"type": "boolean"
},
"originalChars": {
"type": "integer",
"maximum": 9007199254740991,
"minimum": 0
}
},
"additionalProperties": false
},
"statement": {
"type": "object",
"required": [
"text",
"format",
"locale",
"truncated",
"sha256"
],
"properties": {
"text": {
"type": "string"
},
"format": {
"enum": [
"markdown",
"html",
"text"
],
"type": "string"
},
"locale": {
"type": "string",
"minLength": 1
},
"sha256": {
"type": "string",
"pattern": "^[a-f0-9]{64}$"
},
"truncated": {
"type": "boolean"
},
"originalChars": {
"type": "integer",
"maximum": 9007199254740991,
"minimum": 0
}
},
"additionalProperties": false
}
},
"additionalProperties": false
},
"samples": {
"type": "array",
"items": {
"type": "object",
"required": [
"ordinal",
"input",
"output"
],
"properties": {
"input": {
"type": "string"
},
"output": {
"type": "string"
},
"ordinal": {
"type": "integer",
"maximum": 9007199254740991,
"exclusiveMinimum": 0
},
"explanation": {
"type": "string"
}
},
"additionalProperties": false
}
},
"difficulty": {
"type": "object",
"required": [
"scale"
],
"properties": {
"label": {
"type": "string",
"minLength": 1
},
"scale": {
"type": "string",
"minLength": 1
},
"value": {
"type": "number"
}
},
"additionalProperties": false
},
"constraints": {
"type": "array",
"items": {
"type": "string"
}
},
"starterCode": {
"type": "array",
"items": {
"type": "object",
"required": [
"languageKey",
"platformLanguageId",
"code"
],
"properties": {
"code": {
"type": "string"
},
"languageKey": {
"type": "string",
"minLength": 1
},
"platformLanguageId": {
"type": "string",
"minLength": 1
}
},
"additionalProperties": false
}
},
"schemaVersion": {
"type": "string",
"const": "oj.problem-document/v1"
}
},
"additionalProperties": false
},
{
"type": "object",
"required": [
"schemaVersion",
"code",
"layer",
"message",
"retryPolicy",
"userAction"
],
"properties": {
"code": {
"enum": [
"request.invalid",
"capability.unsupported",
"policy.blocked",
"auth.required",
"auth.invalid",
"auth.forbidden",
"challenge.required",
"resource.not_found",
"rate_limited",
"network.timeout",
"upstream.unavailable",
"upstream.schema_changed",
"language.unsupported",
"runner.unavailable",
"runner.sandbox_required",
"confirmation.required",
"confirmation.expired",
"confirmation.mismatch",
"submission.closed",
"submission.rejected",
"submission.outcome_unknown",
"internal"
],
"type": "string"
},
"jobId": {
"type": "string",
"minLength": 1
},
"layer": {
"enum": [
"broker",
"transport",
"protocol",
"auth",
"upstream",
"runner",
"policy"
],
"type": "string"
},
"message": {
"type": "string",
"minLength": 1
},
"platform": {
"enum": [
"luogu",
"leetcode",
"nowcoder",
"codeforces",
"atcoder"
],
"type": "string"
},
"requestId": {
"type": "string",
"minLength": 1
},
"httpStatus": {
"type": "integer",
"maximum": 599,
"minimum": 100
},
"providerId": {
"type": "string",
"minLength": 1
},
"userAction": {
"enum": [
"none",
"retry",
"sign_in",
"solve_challenge",
"change_language",
"open_logs"
],
"type": "string"
},
"retryPolicy": {
"enum": [
"never",
"safe_read",
"poll_only",
"after_user_action"
],
"type": "string"
},
"retryAfterMs": {
"type": "number",
"minimum": 0
},
"upstreamCode": {
"type": "string",
"minLength": 1
},
"schemaVersion": {
"type": "string",
"const": "oj.error/v1"
}
},
"additionalProperties": false
}
]
}oj_fetch_problem annotations
{
"readOnlyHint": true,
"openWorldHint": true,
"idempotentHint": true,
"destructiveHint": false
}oj_search_problems — Find Exact AtCoder Problem
Advertised read-onlyOpen-world
Resolve exactly one contest/task id, atcoder:contest/task id, or canonical task URL. Free-text and catalog crawling are not supported.
oj_search_problems input schema
{
"type": "object",
"$schema": "https://json-schema.org/draft/2020-12/schema",
"required": [
"schemaVersion",
"requestId",
"platform",
"query",
"limit"
],
"properties": {
"limit": {
"type": "integer",
"maximum": 50,
"minimum": 1
},
"query": {
"type": "string",
"maxLength": 300,
"minLength": 1
},
"locale": {
"enum": [
"en",
"ja"
],
"type": "string"
},
"platform": {
"type": "string",
"const": "atcoder"
},
"requestId": {
"type": "string",
"maxLength": 200,
"minLength": 1
},
"schemaVersion": {
"type": "string",
"const": "oj.search-request/v1"
}
},
"additionalProperties": false
}oj_search_problems output schema
{
"type": "object",
"anyOf": [
{
"type": "object",
"required": [
"schemaVersion",
"requestId",
"items",
"source"
],
"properties": {
"items": {
"type": "array",
"items": {
"type": "object",
"required": [
"schemaVersion",
"ref",
"title",
"tags",
"source"
],
"properties": {
"ref": {
"type": "object",
"required": [
"schemaVersion",
"platform",
"nativeId",
"canonicalId",
"url",
"source"
],
"properties": {
"url": {
"type": "string",
"format": "uri"
},
"site": {
"enum": [
"global",
"cn"
],
"type": "string"
},
"source": {
"type": "object",
"required": [
"kind",
"adapterId",
"adapterVersion",
"fetchedAt",
"sourceUrl",
"confidence"
],
"properties": {
"etag": {
"type": "string",
"minLength": 1
},
"kind": {
"enum": [
"official_api",
"official_open_platform",
"page_adapter",
"browser_companion",
"community_adapter",
"manual"
],
"type": "string"
},
"rawRef": {
"type": "string",
"minLength": 1
},
"adapterId": {
"type": "string",
"minLength": 1
},
"fetchedAt": {
"type": "string",
"format": "date-time",
"pattern": "^(?:(?:\\d\\d[2468][048]|\\d\\d[13579][26]|\\d\\d0[48]|[02468][048]00|[13579][26]00)-02-29|\\d{4}-(?:(?:0[13578]|1[02])-(?:0[1-9]|[12]\\d|3[01])|(?:0[469]|11)-(?:0[1-9]|[12]\\d|30)|(?:02)-(?:0[1-9]|1\\d|2[0-8])))T(?:(?:[01]\\d|2[0-3]):[0-5]\\d(?::[0-5]\\d(?:\\.\\d+)?)?(?:Z))$"
},
"sourceUrl": {
"type": "string",
"format": "uri"
},
"confidence": {
"enum": [
"authoritative",
"derived",
"user_supplied"
],
"type": "string"
},
"adapterVersion": {
"type": "string",
"minLength": 1
}
},
"additionalProperties": false
},
"contest": {
"type": "object",
"required": [
"nativeId"
],
"properties": {
"index": {
"type": "string",
"minLength": 1
},
"nativeId": {
"type": "string",
"minLength": 1
}
},
"additionalProperties": false
},
"nativeId": {
"type": "string",
"minLength": 1
},
"platform": {
"enum": [
"luogu",
"leetcode",
"nowcoder",
"codeforces",
"atcoder"
],
"type": "string"
},
"canonicalId": {
"type": "string",
"minLength": 1
},
"schemaVersion": {
"type": "string",
"const": "oj.problem-ref/v1"
}
},
"additionalProperties": false
},
"tags": {
"type": "array",
"items": {
"type": "object",
"required": [
"namespace",
"slug",
"name"
],
"properties": {
"id": {
"type": "string",
"minLength": 1
},
"name": {
"type": "string",
"minLength": 1
},
"slug": {
"type": "string",
"minLength": 1
},
"namespace": {
"enum": [
"platform",
"canonical"
],
"type": "string"
}
},
"additionalProperties": false
}
},
"title": {
"type": "string",
"minLength": 1
},
"source": {
"type": "object",
"required": [
"kind",
"adapterId",
"adapterVersion",
"fetchedAt",
"sourceUrl",
"confidence"
],
"properties": {
"etag": {
"type": "string",
"minLength": 1
},
"kind": {
"enum": [
"official_api",
"official_open_platform",
"page_adapter",
"browser_companion",
"community_adapter",
"manual"
],
"type": "string"
},
"rawRef": {
"type": "string",
"minLength": 1
},
"adapterId": {
"type": "string",
"minLength": 1
},
"fetchedAt": {
"type": "string",
"format": "date-time",
"pattern": "^(?:(?:\\d\\d[2468][048]|\\d\\d[13579][26]|\\d\\d0[48]|[02468][048]00|[13579][26]00)-02-29|\\d{4}-(?:(?:0[13578]|1[02])-(?:0[1-9]|[12]\\d|3[01])|(?:0[469]|11)-(?:0[1-9]|[12]\\d|30)|(?:02)-(?:0[1-9]|1\\d|2[0-8])))T(?:(?:[01]\\d|2[0-3]):[0-5]\\d(?::[0-5]\\d(?:\\.\\d+)?)?(?:Z))$"
},
"sourceUrl": {
"type": "string",
"format": "uri"
},
"confidence": {
"enum": [
"authoritative",
"derived",
"user_supplied"
],
"type": "string"
},
"adapterVersion": {
"type": "string",
"minLength": 1
}
},
"additionalProperties": false
},
"acceptance": {
"type": "object",
"properties": {
"ratio": {
"type": "number",
"maximum": 1,
"minimum": 0
},
"accepted": {
"type": "integer",
"maximum": 9007199254740991,
"minimum": 0
},
"submissions": {
"type": "integer",
"maximum": 9007199254740991,
"minimum": 0
}
},
"additionalProperties": false
},
"difficulty": {
"type": "object",
"required": [
"scale"
],
"properties": {
"label": {
"type": "string",
"minLength": 1
},
"scale": {
"type": "string",
"minLength": 1
},
"value": {
"type": "number"
}
},
"additionalProperties": false
},
"contestLabel": {
"type": "string",
"minLength": 1
},
"schemaVersion": {
"type": "string",
"const": "oj.problem-summary/v1"
}
},
"additionalProperties": false
}
},
"source": {
"type": "object",
"required": [
"kind",
"adapterId",
"adapterVersion",
"fetchedAt",
"sourceUrl",
"confidence"
],
"properties": {
"etag": {
"type": "string",
"minLength": 1
},
"kind": {
"enum": [
"official_api",
"official_open_platform",
"page_adapter",
"browser_companion",
"community_adapter",
"manual"
],
"type": "string"
},
"rawRef": {
"type": "string",
"minLength": 1
},
"adapterId": {
"type": "string",
"minLength": 1
},
"fetchedAt": {
"type": "string",
"format": "date-time",
"pattern": "^(?:(?:\\d\\d[2468][048]|\\d\\d[13579][26]|\\d\\d0[48]|[02468][048]00|[13579][26]00)-02-29|\\d{4}-(?:(?:0[13578]|1[02])-(?:0[1-9]|[12]\\d|3[01])|(?:0[469]|11)-(?:0[1-9]|[12]\\d|30)|(?:02)-(?:0[1-9]|1\\d|2[0-8])))T(?:(?:[01]\\d|2[0-3]):[0-5]\\d(?::[0-5]\\d(?:\\.\\d+)?)?(?:Z))$"
},
"sourceUrl": {
"type": "string",
"format": "uri"
},
"confidence": {
"enum": [
"authoritative",
"derived",
"user_supplied"
],
"type": "string"
},
"adapterVersion": {
"type": "string",
"minLength": 1
}
},
"additionalProperties": false
},
"requestId": {
"type": "string",
"minLength": 1
},
"nextCursor": {
"type": "string",
"minLength": 1
},
"schemaVersion": {
"type": "string",
"const": "oj.search-result/v1"
}
},
"additionalProperties": false
},
{
"type": "object",
"required": [
"schemaVersion",
"code",
"layer",
"message",
"retryPolicy",
"userAction"
],
"properties": {
"code": {
"enum": [
"request.invalid",
"capability.unsupported",
"policy.blocked",
"auth.required",
"auth.invalid",
"auth.forbidden",
"challenge.required",
"resource.not_found",
"rate_limited",
"network.timeout",
"upstream.unavailable",
"upstream.schema_changed",
"language.unsupported",
"runner.unavailable",
"runner.sandbox_required",
"confirmation.required",
"confirmation.expired",
"confirmation.mismatch",
"submission.closed",
"submission.rejected",
"submission.outcome_unknown",
"internal"
],
"type": "string"
},
"jobId": {
"type": "string",
"minLength": 1
},
"layer": {
"enum": [
"broker",
"transport",
"protocol",
"auth",
"upstream",
"runner",
"policy"
],
"type": "string"
},
"message": {
"type": "string",
"minLength": 1
},
"platform": {
"enum": [
"luogu",
"leetcode",
"nowcoder",
"codeforces",
"atcoder"
],
"type": "string"
},
"requestId": {
"type": "string",
"minLength": 1
},
"httpStatus": {
"type": "integer",
"maximum": 599,
"minimum": 100
},
"providerId": {
"type": "string",
"minLength": 1
},
"userAction": {
"enum": [
"none",
"retry",
"sign_in",
"solve_challenge",
"change_language",
"open_logs"
],
"type": "string"
},
"retryPolicy": {
"enum": [
"never",
"safe_read",
"poll_only",
"after_user_action"
],
"type": "string"
},
"retryAfterMs": {
"type": "number",
"minimum": 0
},
"upstreamCode": {
"type": "string",
"minLength": 1
},
"schemaVersion": {
"type": "string",
"const": "oj.error/v1"
}
},
"additionalProperties": false
}
]
}oj_search_problems annotations
{
"readOnlyHint": true,
"openWorldHint": true,
"idempotentHint": true,
"destructiveHint": false
}Prompts
Not advertised
Resources
Not advertised
90-day uptime
A lightweight connection check about every six hours, sampled on hosts with many listings. It shows the server answered, not that its tools work.
- 2026-11-06: 1 of 1 checks answered
- 2026-11-07: 1 of 1 checks answered
30-day availability
Aggregated from read-only remote checks; this is not a tool-execution or security guarantee.
- Successful checks
- 1 of 1 (100%)
- Average latency
- 183 ms
- 95th percentile latency
- 183 ms
Maintenance history
Public check and source-refresh events. Editorial and ownership records remain private.
- · probe · passed · 183 ms · metadata changed · 4 tool(s)
Connect from your client
Each snippet registers the same endpoint; pick the client you use.
Claude Code
Claude Code configuration
claude mcp add --transport http atcoder-mcp-server https://api.ksrnyx.top/oj-mcp/atcoder/mcpCodex
Codex configuration
codex mcp add atcoder-mcp-server --url https://api.ksrnyx.top/oj-mcp/atcoder/mcpCursor
Cursor configuration
{
"mcpServers": {
"atcoder-mcp-server": {
"url": "https://api.ksrnyx.top/oj-mcp/atcoder/mcp"
}
}
}Cline
Cline configuration
{
"mcpServers": {
"atcoder-mcp-server": {
"type": "streamableHttp",
"url": "https://api.ksrnyx.top/oj-mcp/atcoder/mcp",
"disabled": false
}
}
}VS Code
VS Code configuration
{
"servers": {
"atcoder-mcp-server": {
"type": "http",
"url": "https://api.ksrnyx.top/oj-mcp/atcoder/mcp"
}
}
}Gemini CLI
Gemini CLI configuration
gemini mcp add --transport http atcoder-mcp-server https://api.ksrnyx.top/oj-mcp/atcoder/mcpClaude Desktop
Claude Desktop configuration
https://api.ksrnyx.top/oj-mcp/atcoder/mcpWindsurf
Windsurf configuration
{
"mcpServers": {
"atcoder-mcp-server": {
"serverUrl": "https://api.ksrnyx.top/oj-mcp/atcoder/mcp"
}
}
}Let your agent find its tools
Find servers like AtCoder MCP Server from your agent. Add Koskamo once to search the index for endpoints, access requirements, and client setup. Public discovery needs no key.