{ "meta": { "attribution": "Anchor Terminal (https://www.anchorterminal.com)", "docs": "https://www.anchorterminal.com/docs/", "generatedAt": "2026-10-09", "license": "CC-BY-4.0", "method": "https://www.anchorterminal.com/benchmark/", "methodology": "0.4", "openapi": "https://www.anchorterminal.com/openapi.json", "preview": false, "run": "2026-10-01", "runLabel": "October 2026 research run" }, "tool": { "slug": "clickhouse-mcp-server", "name": "ClickHouse MCP Server", "vendor": "ClickHouse", "vendorUrl": "https://clickhouse.com", "kind": "mcp", "category": "data", "summary": "ClickHouse's open-source MCP server for ClickHouse databases. The owner runs it locally or self-hosted, and it gives agents SQL queries, database and table listing, and an optional embedded chDB engine. Queries are read-only by default.", "url": "https://www.anchorterminal.com/tools/clickhouse-mcp-server", "markdownUrl": "https://www.anchorterminal.com/tools/clickhouse-mcp-server.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/clickhouse-mcp-server.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/clickhouse-mcp-server.json", "repo": "https://github.com/ClickHouse/mcp-clickhouse", "license": "Apache-2.0", "transports": [ "stdio", "streamable-http", "sse" ], "packages": [ { "registry": "pypi", "name": "mcp-clickhouse" }, { "registry": "oci", "name": "ghcr.io/clickhouse/mcp-clickhouse" } ], "auth": "mixed", "authNotes": "The server signs in to ClickHouse with `CLICKHOUSE_USER` and `CLICKHOUSE_PASSWORD`, or with an X.509 client certificate (`CLICKHOUSE_CLIENT_CERT`, added in 0.7.0), and can set a role with `CLICKHOUSE_ROLE`. An admin creates the user, self-serve, and ClickHouse grants set what it can do. stdio needs no caller credential. The HTTP and SSE transports refuse to start unless one of a static bearer token (`CLICKHOUSE_MCP_AUTH_TOKEN`), a FastMCP OAuth or OIDC provider (`FASTMCP_SERVER_AUTH`) or `CLICKHOUSE_MCP_AUTH_DISABLED=true` is set. Every caller shares the one ClickHouse user unless custom middleware overrides the connection per request.", "pricing": "free", "pricingNotes": "Free and open source under Apache-2.0, with nothing to buy for the server. It needs a ClickHouse database, which can be self-managed open-source ClickHouse, ClickHouse Cloud or the embedded chDB engine. The README gives a public SQL playground (`sql-clickhouse.clickhouse.com`, user `demo`, empty password) for trying it with no account. ClickHouse Cloud prices were not checked. The separate hosted Remote MCP server is a ClickHouse Cloud feature and is not what this listing grades (checked 2026-10-09).", "priceSummary": "Free ยท OSS", "where": "local", "x402": { "level": "no", "evidence": "No x402, MPP or L402 in the README, the changelog or the source (checked 2026-10-09).", "endpoints": [] }, "toolCount": 3, "popularity": { "githubStars": 883, "npmWeekly": null, "pypiWeekly": 47206, "asOf": "2026-10-09" }, "docsUrl": "https://github.com/ClickHouse/mcp-clickhouse#readme", "llmsTxt": "https://clickhouse.com/docs/llms.txt", "registryName": "io.github.ClickHouse/mcp-clickhouse", "capabilities": [ "db.sql" ], "tags": [ "official", "local", "open-source", "self-hosted", "mcp", "python", "docker", "read-only-mode", "database" ], "lastRelease": "2026-09-21", "graded": true, "anchor": { "graded": true, "score": 64.6, "grade": "B", "agentReady": false, "rank": 312, "ranked": true, "rankOf": 842, "categoryRank": 5, "methodology": "0.4", "run": "2026-10-01", "scores": { "ergonomics": 65, "maintenance": 94, "payments": 60, "reliability": 74, "schema": 79, "security": 66, "transparency": 82 }, "pending": [ "performance", "tasks" ], "breakdown": [ { "key": "reliability", "name": "Reliability", "weight": 16, "effectiveWeight": 20, "score": 74, "points": 14.8, "reason": "Scored as local software, since the owner runs it over stdio or its own HTTP listener. Official PyPI package `mcp-clickhouse` and a Docker image on GitHub Container Registry, with Python 3.10 to 3.14 stated (20). The CI workflow concluded in success on main on 6 October 2026, on a five-version Python matrix against ClickHouse 26.3, and the repository holds 403 test functions (25). Three open issues and five open pull requests. Issue #223 on unbounded `run_query` results has been open since 23 August 2026 with no reply, and #155 on per-user access has ten comments (20 of 25). A changelog with a labelled breaking change in 0.5.0 and Compatibility sections in 0.6.0 and 0.7.0, but the changelog file dates only from 14 April 2026, 0.3.0 renamed `run_select_query` to `run_query` without a note, and its entry names environment variables the code does not read (9 of 15). Version 0.7.0, with no stability declaration found (0)." }, { "key": "performance", "name": "Performance", "weight": 10, "effectiveWeight": 0, "pending": true, "points": 0, "reason": "Pending. Latency is measured per call by our probes, which haven't run yet, so this run doesn't score it. Its weight is shared across the assessed categories until the first probe window closes." }, { "key": "schema", "name": "Schema \u0026 documentation", "weight": 13, "effectiveWeight": 16.25, "score": 79, "points": 12.84, "reason": "Each tool is built from a typed Python signature, so inputs carry JSON Schema, read from the source since we do not run vendor software. `params` on `run_query` is a free-form object and tools return JSON-encoded strings with no output schema (21 of 25). clickhouse.com serves llms.txt, a docs llms.txt and a Markdown form of each docs page, and the README is Markdown (10). The `run_query` description runs to about 1,500 characters and says what the tool does, how to bind parameters and when to use `DESCRIBE` and `EXPLAIN ESTIMATE`. `list_tables` documents every argument and the response shape. `list_databases` has one line (16 of 20). `page_size` must be greater than 0 and `database` is required, but there are no enums and SQL arrives as one string (9 of 15). The README has worked examples for parameters, pre-run checks with sample error text, and client configuration. No catalogue of error responses was found (10 of 15). Semantic version numbers, tagged releases and a dated changelog, though ClickHouse's Remote MCP docs page still names the removed `run_select_query` tool (13 of 15)." }, { "key": "ergonomics", "name": "Agent ergonomics", "weight": 13, "effectiveWeight": 16.25, "score": 65, "points": 10.56, "reason": "Three tools by default and four with chDB, one of them with a long description (25). `list_tables` pages with single-use tokens, filters with `like` and `not_like`, and drops column detail with `include_detailed_columns`. `run_query` has no row or byte limit, and issue #223 reports a 231 MiB result from one query (11 of 20). ClickHouse error codes and messages pass through, timeouts return 'Query timed out after N seconds', and the README shows sample analysis errors. No documented error list (13 of 20). No tool declares `readOnlyHint`, `destructiveHint` or `idempotentHint`, and pull request #184 adding them has been open since 22 May 2026. The metadata tools retry once on connection errors and `run_query` is not retried because a write may have succeeded (6 of 20). `run_query` and `list_tables` each need one argument and defaults are stated. The server is a Python package only (10 of 15)." }, { "key": "security", "name": "Security \u0026 auth", "weight": 14, "effectiveWeight": 17.5, "score": 66, "points": 11.55, "reason": "The server holds one ClickHouse user and password, or an X.509 client certificate since 0.7.0, which ClickHouse grants and roles can scope and an admin can revoke. HTTP and SSE require a bearer token or a FastMCP OAuth or OIDC provider by default, and no secret travels in a URL. Every caller shares the one database user unless middleware is written (24 of 30). Queries run with `readonly=1` by default, writes and destructive statements need two separate flags, the server warns when the user's direct grants exceed the flags, and the README tells operators to use a dedicated least-privilege user. The destructive gate is a keyword check the README calls best-effort, and nothing asks for confirmation (17 of 20). Query results reach the model as stored. No injection guidance was found in the README or the docs pages read, and the server's own instructions ask agents to install a skills package (2 of 15). Each query's SQL is logged at INFO, ClickHouse's `system.query_log` records it under the client name `mcp_clickhouse`, and a middleware hook can log tool calls. No per-caller identity reaches ClickHouse (9 of 15). ClickHouse has a valid security.txt, a Bugcrowd bounty programme, and SOC 2 Type 2 and ISO 27001 on its trust centre. This repository has no SECURITY.md and no published advisories, though 0.3.0 and 0.5.0 carried security fixes (14 of 20)." }, { "key": "payments", "name": "Payments \u0026 pricing", "weight": 10, "effectiveWeight": 12.5, "score": 60, "points": 7.5, "reason": "Read with the self-hosted rule. The server is free under Apache-2.0 and needs no signup of its own, so 20 + 20 + 20. No x402, MPP or L402 (0). It needs a ClickHouse database, which can be free open-source ClickHouse, the embedded chDB engine or the public SQL playground the README names. ClickHouse Cloud prices were not checked. The hosted Remote MCP server is a ClickHouse Cloud feature and is not what this listing grades." }, { "key": "tasks", "name": "Task success", "weight": 10, "effectiveWeight": 0, "pending": true, "points": 0, "reason": "Pending. Task success needs the category task suites run through each tool, which haven't run yet, so this run doesn't score it. Its weight is shared across the assessed categories until then. A data provider's data-quality score is published on its listing now and becomes half of this category when it's scored." }, { "key": "maintenance", "name": "Maintenance \u0026 community", "weight": 7, "effectiveWeight": 8.75, "score": 94, "points": 8.23, "reason": "v0.7.0 was tagged and released on GitHub on 21 September 2026, 18 days before the check (30). Four tagged releases in the 90 days before the check, 0.4.1 on 17 July, 0.5.0 on 1 September, 0.6.0 on 3 September and 0.7.0 (20). Three open issues against a dozen closed between July and October 2026, most with a maintainer reply and a fix version. Issue #223 has had no reply in six weeks and pull request #184 has been open since May (20 of 25). Listed in the official MCP registry as `io.github.ClickHouse/mcp-clickhouse`, a GitHub-verified namespace, with 0.7.0 published on 21 September 2026 and marked latest (15). Dependabot updates merged on 1 October 2026, a lock file, and a CI matrix that tests the minimum supported driver. `server.json` on main still says 0.6.0 (9 of 10)." }, { "key": "transparency", "name": "Transparency \u0026 trust", "weight": 7, "effectiveWeight": 8.75, "score": 82, "points": 7.18, "note": "editorial 76, provenance 87", "reason": "Apache-2.0 (30). Local software that connects only to the configured ClickHouse. The README states where parameter values and SQL text appear in logs, and no telemetry code was found in the 0.7.0 source. Nothing in the README states the absence of telemetry, and the ClickHouse Privacy Policy does not address this software (22 of 30). No deprecation policy. The SSE transport is marked deprecated in 0.6.0 with no removal date, and `run_select_query` was removed in 0.3.0 with no prior notice found (8 of 20). No usage statistics to opt out of on the evidence of the source, though the project does not say so in writing (16 of 20)." } ], "assessment": { "date": "2026-10-09", "basis": "public evidence", "confidence": "medium", "notes": { "ergonomics": "Three tools by default and four with chDB, one of them with a long description (25). `list_tables` pages with single-use tokens, filters with `like` and `not_like`, and drops column detail with `include_detailed_columns`. `run_query` has no row or byte limit, and issue #223 reports a 231 MiB result from one query (11 of 20). ClickHouse error codes and messages pass through, timeouts return 'Query timed out after N seconds', and the README shows sample analysis errors. No documented error list (13 of 20). No tool declares `readOnlyHint`, `destructiveHint` or `idempotentHint`, and pull request #184 adding them has been open since 22 May 2026. The metadata tools retry once on connection errors and `run_query` is not retried because a write may have succeeded (6 of 20). `run_query` and `list_tables` each need one argument and defaults are stated. The server is a Python package only (10 of 15).", "maintenance": "v0.7.0 was tagged and released on GitHub on 21 September 2026, 18 days before the check (30). Four tagged releases in the 90 days before the check, 0.4.1 on 17 July, 0.5.0 on 1 September, 0.6.0 on 3 September and 0.7.0 (20). Three open issues against a dozen closed between July and October 2026, most with a maintainer reply and a fix version. Issue #223 has had no reply in six weeks and pull request #184 has been open since May (20 of 25). Listed in the official MCP registry as `io.github.ClickHouse/mcp-clickhouse`, a GitHub-verified namespace, with 0.7.0 published on 21 September 2026 and marked latest (15). Dependabot updates merged on 1 October 2026, a lock file, and a CI matrix that tests the minimum supported driver. `server.json` on main still says 0.6.0 (9 of 10).", "payments": "Read with the self-hosted rule. The server is free under Apache-2.0 and needs no signup of its own, so 20 + 20 + 20. No x402, MPP or L402 (0). It needs a ClickHouse database, which can be free open-source ClickHouse, the embedded chDB engine or the public SQL playground the README names. ClickHouse Cloud prices were not checked. The hosted Remote MCP server is a ClickHouse Cloud feature and is not what this listing grades.", "reliability": "Scored as local software, since the owner runs it over stdio or its own HTTP listener. Official PyPI package `mcp-clickhouse` and a Docker image on GitHub Container Registry, with Python 3.10 to 3.14 stated (20). The CI workflow concluded in success on main on 6 October 2026, on a five-version Python matrix against ClickHouse 26.3, and the repository holds 403 test functions (25). Three open issues and five open pull requests. Issue #223 on unbounded `run_query` results has been open since 23 August 2026 with no reply, and #155 on per-user access has ten comments (20 of 25). A changelog with a labelled breaking change in 0.5.0 and Compatibility sections in 0.6.0 and 0.7.0, but the changelog file dates only from 14 April 2026, 0.3.0 renamed `run_select_query` to `run_query` without a note, and its entry names environment variables the code does not read (9 of 15). Version 0.7.0, with no stability declaration found (0).", "schema": "Each tool is built from a typed Python signature, so inputs carry JSON Schema, read from the source since we do not run vendor software. `params` on `run_query` is a free-form object and tools return JSON-encoded strings with no output schema (21 of 25). clickhouse.com serves llms.txt, a docs llms.txt and a Markdown form of each docs page, and the README is Markdown (10). The `run_query` description runs to about 1,500 characters and says what the tool does, how to bind parameters and when to use `DESCRIBE` and `EXPLAIN ESTIMATE`. `list_tables` documents every argument and the response shape. `list_databases` has one line (16 of 20). `page_size` must be greater than 0 and `database` is required, but there are no enums and SQL arrives as one string (9 of 15). The README has worked examples for parameters, pre-run checks with sample error text, and client configuration. No catalogue of error responses was found (10 of 15). Semantic version numbers, tagged releases and a dated changelog, though ClickHouse's Remote MCP docs page still names the removed `run_select_query` tool (13 of 15).", "security": "The server holds one ClickHouse user and password, or an X.509 client certificate since 0.7.0, which ClickHouse grants and roles can scope and an admin can revoke. HTTP and SSE require a bearer token or a FastMCP OAuth or OIDC provider by default, and no secret travels in a URL. Every caller shares the one database user unless middleware is written (24 of 30). Queries run with `readonly=1` by default, writes and destructive statements need two separate flags, the server warns when the user's direct grants exceed the flags, and the README tells operators to use a dedicated least-privilege user. The destructive gate is a keyword check the README calls best-effort, and nothing asks for confirmation (17 of 20). Query results reach the model as stored. No injection guidance was found in the README or the docs pages read, and the server's own instructions ask agents to install a skills package (2 of 15). Each query's SQL is logged at INFO, ClickHouse's `system.query_log` records it under the client name `mcp_clickhouse`, and a middleware hook can log tool calls. No per-caller identity reaches ClickHouse (9 of 15). ClickHouse has a valid security.txt, a Bugcrowd bounty programme, and SOC 2 Type 2 and ISO 27001 on its trust centre. This repository has no SECURITY.md and no published advisories, though 0.3.0 and 0.5.0 carried security fixes (14 of 20).", "transparency": "Apache-2.0 (30). Local software that connects only to the configured ClickHouse. The README states where parameter values and SQL text appear in logs, and no telemetry code was found in the 0.7.0 source. Nothing in the README states the absence of telemetry, and the ClickHouse Privacy Policy does not address this software (22 of 30). No deprecation policy. The SSE transport is marked deprecated in 0.6.0 with no removal date, and `run_select_query` was removed in 0.3.0 with no prior notice found (8 of 20). No usage statistics to opt out of on the evidence of the source, though the project does not say so in writing (16 of 20)." }, "sources": [ { "what": "README, tools, authentication, write gates and environment variables", "url": "https://github.com/ClickHouse/mcp-clickhouse", "seen": "2026-10-09" }, { "what": "changelog, 0.1.0 to 0.7.0", "url": "https://github.com/ClickHouse/mcp-clickhouse/blob/main/CHANGELOG.md", "seen": "2026-10-09" }, { "what": "tool registration and descriptions, read from a clone of main at d21fe75 (7 October 2026)", "url": "https://github.com/ClickHouse/mcp-clickhouse/blob/main/mcp_clickhouse/mcp_server.py", "seen": "2026-10-09" }, { "what": "server instructions addressed to agents", "url": "https://github.com/ClickHouse/mcp-clickhouse/blob/main/mcp_clickhouse/skills_advisor.py", "seen": "2026-10-09" }, { "what": "package metadata, dependencies and supported Python versions", "url": "https://github.com/ClickHouse/mcp-clickhouse/blob/main/pyproject.toml", "seen": "2026-10-09" }, { "what": "CI workflow definition", "url": "https://github.com/ClickHouse/mcp-clickhouse/blob/main/.github/workflows/ci.yaml", "seen": "2026-10-09" }, { "what": "workflow runs on main", "url": "https://api.github.com/repos/ClickHouse/mcp-clickhouse/actions/runs?branch=main", "seen": "2026-10-09" }, { "what": "repository statistics", "url": "https://api.github.com/repos/ClickHouse/mcp-clickhouse", "seen": "2026-10-09" }, { "what": "open and closed issues and pull requests", "url": "https://github.com/ClickHouse/mcp-clickhouse/issues", "seen": "2026-10-09" }, { "what": "issue #223, unbounded run_query results", "url": "https://github.com/ClickHouse/mcp-clickhouse/issues/223", "seen": "2026-10-09" }, { "what": "issue #131, DDL through run_select_query", "url": "https://github.com/ClickHouse/mcp-clickhouse/issues/131", "seen": "2026-10-09" }, { "what": "issue #188, FastMCP advisories flagged by scanners, closed as fixed in 0.6.0", "url": "https://github.com/ClickHouse/mcp-clickhouse/issues/188", "seen": "2026-10-09" }, { "what": "GitHub release notes, v0.1.13 to v0.7.0", "url": "https://api.github.com/repos/ClickHouse/mcp-clickhouse/releases", "seen": "2026-10-09" }, { "what": "repository security advisories (none)", "url": "https://api.github.com/repos/ClickHouse/mcp-clickhouse/security-advisories", "seen": "2026-10-09" }, { "what": "MCP registry search", "url": "https://registry.modelcontextprotocol.io/v0/servers?search=clickhouse", "seen": "2026-10-09" }, { "what": "PyPI weekly downloads", "url": "https://pypistats.org/api/packages/mcp-clickhouse/recent", "seen": "2026-10-09" }, { "what": "ClickHouse docs page on the open-source MCP server", "url": "https://clickhouse.com/docs/products/agentic-data-stack/components/mcp-server.md", "seen": "2026-10-09" }, { "what": "Remote MCP in Cloud, with the comparison table", "url": "https://clickhouse.com/docs/products/cloud/features/ai-ml/remote-mcp.md", "seen": "2026-10-09" }, { "what": "llms.txt", "url": "https://clickhouse.com/llms.txt", "seen": "2026-10-09" }, { "what": "docs llms.txt", "url": "https://clickhouse.com/docs/llms.txt", "seen": "2026-10-09" }, { "what": "robots.txt, with Content-Signal ai-input=yes", "url": "https://clickhouse.com/robots.txt", "seen": "2026-10-09" }, { "what": "security.txt", "url": "https://clickhouse.com/.well-known/security.txt", "seen": "2026-10-09" }, { "what": "ClickHouse security policy and Bugcrowd programme", "url": "https://github.com/ClickHouse/ClickHouse/blob/master/SECURITY.md", "seen": "2026-10-09" }, { "what": "trust centre, compliance list", "url": "https://trust.clickhouse.com/", "seen": "2026-10-09" }, { "what": "privacy policy", "url": "https://clickhouse.com/legal/privacy-policy", "seen": "2026-10-09" }, { "what": "domain registration", "url": "https://rdap.verisign.com/com/v1/domain/clickhouse.com", "seen": "2026-10-09" } ], "openQuestions": [ "The lead said no hosted server was shown. ClickHouse Cloud has a hosted Remote MCP server at https://mcp.clickhouse.cloud/mcp with OAuth 2.0 or a Cloud API key and 13 read-only tools. It is a separate Cloud feature and this listing grades the open-source server only", "unchecked: the PyPI project page, which answered with a JavaScript client challenge, and the PyPI JSON API, which robots.txt disallows. The 0.7.0 release date rests on the git tag, the GitHub release and the MCP registry entry, all 21 September 2026. The changelog heading says 18 September", "unchecked: tool definitions as a client receives them from `tools/list`. We did not run the server, so input schemas and the absence of annotations are read from the source", "unchecked: the claim in issue #131 that DDL ran under `readonly=1` and that a production table was dropped. It is the reporter's account and no maintainer confirmed or disputed it in the thread", "unchecked: ClickHouse Cloud pricing and its trial, which matter only when the server points at ClickHouse Cloud", "unchecked: the Bugcrowd programme page and whether mcp-clickhouse is in scope", "unchecked: the GitHub Container Registry image page, which rests on the changelog and `server.json`", "No privacy document addresses this software, so `provenance.privacy` and `provenance.terms` are both left out", "The server's MCP instructions tell agents to run `npx -y skills add clickhouse/agent-skills --all`. Recorded as a fact with no deduction, and not acted on" ] }, "negative": -8, "negativeNotes": [ "-3: release 0.3.0 on 14 April 2026 renamed the `run_select_query` tool to `run_query` (commit d82fc87, pull request #93). Neither the changelog entry nor the GitHub release notes for 0.3.0 mention the rename, and ClickHouse's Remote MCP docs page still names the old tool (https://github.com/ClickHouse/mcp-clickhouse/blob/main/CHANGELOG.md).", "-3: issue #131, opened on 18 February 2026, reports that `run_select_query` ran CREATE and DROP statements against a ClickHouse Cloud user with full privileges although the docs said every query ran with `readonly=1`, and that an agent dropped a production table. This is the reporter's account. A maintainer closed it on 20 April 2026 as addressed by pull request #93 in 0.3.0. No advisory was published, and the fix shipped, so a reduced deduction (https://github.com/ClickHouse/mcp-clickhouse/issues/131).", "-2: 0.5.0 on 1 September 2026 closed a `fastmcp run` launch path that served HTTP without authentication and fixed TRUNCATE and `ALTER TABLE ... DROP` forms that the destructive gate had let through with write access on. Both are described in the changelog and fixed, with no advisory, so a reduced deduction (https://github.com/ClickHouse/mcp-clickhouse/blob/main/CHANGELOG.md)." ], "verdict": "Queries run with `readonly=1` unless the operator sets a write flag, and a second flag gates destructive statements. `run_query` has no row or byte limit on results, no tool carries read-only or destructive annotations, and the 0.3.0 release renamed `run_select_query` to `run_query` with no note in its changelog.", "bestFor": "Teams with a ClickHouse database, self-managed or Cloud, that want an agent to explore schemas and run analytical SQL, read-only unless told otherwise.", "strengths": [ "Read-only by default through ClickHouse's `readonly=1` setting, with `CLICKHOUSE_ALLOW_WRITE_ACCESS` and `CLICKHOUSE_ALLOW_DROP` as separate opt-ins", "Three tools by default (`run_query`, `list_databases`, `list_tables`) and a fourth, `run_chdb_select_query`, only when chDB is enabled", "HTTP and SSE transports refuse to start without a bearer token, a FastMCP OAuth or OIDC provider, or an explicit disable flag, and validate Host and Origin headers", "CI passed on main on 6 October 2026 across Python 3.10 to 3.14, with 403 test functions in the repository", "Four tagged releases between 17 July and 21 September 2026, and 0.7.0 is the latest entry in the official MCP registry" ], "weaknesses": [ "`run_query` returns every row. Issue #223, open since 23 August 2026 with no reply, reports a 231 MiB result from one `SELECT *`", "No tool declares `readOnlyHint` or `destructiveHint`. Pull request #184 adding annotations has been open since 22 May 2026", "Release 0.3.0 renamed `run_select_query` to `run_query` without saying so in its changelog or release notes, and ClickHouse's Remote MCP docs page still uses the old name", "The destructive-statement gate is a keyword check in the server, which the README calls a best-effort guard and not a security boundary", "No prompt-injection guidance for query results was found, the repository has no SECURITY.md, and no advisory covers the security fixes in 0.3.0 and 0.5.0" ], "agentNotes": [ "Put a `LIMIT` on every `run_query` call. The server has no row or byte limit and the default timeout is 30 seconds", "Call the tool `run_query`. ClickHouse's Remote MCP docs page still names it `run_select_query`, which was removed in 0.3.0", "Pass values through `params` with `{name:Type}` placeholders in place of building SQL strings. Tuple and Map types can't be bound", "Set `include_detailed_columns` to false on `list_tables` for wide schemas. Page tokens are single-use and expire after one hour", "Connect with a dedicated ClickHouse user holding only the grants needed, and point `CLICKHOUSE_PORT` at the HTTP interface (8123 or 8443), not 9000" ], "metrics": { "kind": "local", "measured": false }, "reviewCount": 0, "avgRating": 0, "history": [ { "basis": "public evidence", "confidence": "medium", "grade": "B", "methodology": "0.4", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 64.6 } ], "editorialScores": { "ergonomics": 65, "maintenance": 94, "payments": 60, "reliability": 74, "schema": 79, "security": 66, "transparency": 76 }, "provenanceScore": 87 }, "connect": { "install": "python3 -m pip install mcp-clickhouse", "config": { "mcpServers": { "mcp-clickhouse": { "args": [ "run", "--with", "mcp-clickhouse", "--python", "3.12", "mcp-clickhouse" ], "command": "uv", "env": { "CLICKHOUSE_CONNECT_TIMEOUT": "30", "CLICKHOUSE_HOST": "\u003cclickhouse-host\u003e", "CLICKHOUSE_PASSWORD": "\u003cclickhouse-password\u003e", "CLICKHOUSE_PORT": "\u003cclickhouse-port\u003e", "CLICKHOUSE_SECURE": "true", "CLICKHOUSE_USER": "\u003cclickhouse-user\u003e", "CLICKHOUSE_VERIFY": "true" } } } } }, "letme": { "capability": "https://letme.dev/db.sql", "tool": "https://letme.dev/clickhouse-mcp-server" }, "notable": [ "Three tools by default, `run_query`, `list_databases` and `list_tables`, plus `run_chdb_select_query` and one prompt when `CHDB_ENABLED=true` and the `chdb` extra is installed (https://github.com/ClickHouse/mcp-clickhouse#features)", "Queries run with ClickHouse's `readonly=1` setting by default. `CLICKHOUSE_ALLOW_WRITE_ACCESS=true` allows DDL and inserts, and `CLICKHOUSE_ALLOW_DROP=true` is needed as well for DROP, TRUNCATE, DELETE, UPDATE and similar. The README calls the second gate a best-effort accident guard, not a security boundary (https://github.com/ClickHouse/mcp-clickhouse#destructive-operation-protection)", "0.7.0 added a `params` object on `run_query` for ClickHouse `{name:Type}` placeholders, and the description points to `DESCRIBE (\u003cquery\u003e)` and `EXPLAIN ESTIMATE \u003cquery\u003e` as optional checks before a query runs (https://github.com/ClickHouse/mcp-clickhouse/blob/main/CHANGELOG.md)", "`run_query` has no limit on result size. Issue #223 of 23 August 2026 reports 3 million rows and a 231 MiB payload from one `SELECT *` inside the 30-second default timeout, and pull request #224 to bound it is open (https://github.com/ClickHouse/mcp-clickhouse/issues/223)", "0.5.0 on 1 September 2026 added Host and Origin validation on HTTP and SSE as a labelled breaking change, closed a `fastmcp run` launch path that served without authentication, and widened the destructive gate to statements that had run with write access alone (https://github.com/ClickHouse/mcp-clickhouse/blob/main/CHANGELOG.md)", "0.6.0 moved to FastMCP 4 and the README says the server implements MCP `2026-07-28` with legacy handshakes from `2024-11-05` to `2025-11-25`. The standalone SSE transport is deprecated with no removal date (https://github.com/ClickHouse/mcp-clickhouse/blob/main/CHANGELOG.md)", "The server's MCP instructions tell agents to consider ClickHouse's Agent Skills and give an `npx -y skills add clickhouse/agent-skills --all` command. We record this as a fact and did not act on it (https://github.com/ClickHouse/mcp-clickhouse/blob/main/mcp_clickhouse/skills_advisor.py)", "ClickHouse Cloud has a separate hosted Remote MCP server at `https://mcp.clickhouse.cloud/mcp` with OAuth 2.0 or a Cloud API key and 13 read-only tools, for Cloud services only (https://clickhouse.com/docs/products/cloud/features/ai-ml/remote-mcp)" ], "area": "developer", "details": [ { "label": "What is graded", "value": "The open-source server in ClickHouse/mcp-clickhouse, version 0.7.0, which the owner runs. ClickHouse Cloud's hosted Remote MCP server at `https://mcp.clickhouse.cloud/mcp` is a separate product with 13 read-only tools and is not graded here" }, { "label": "Install", "value": "`python3 -m pip install mcp-clickhouse` or `uv run --with mcp-clickhouse --python 3.12 mcp-clickhouse`. Python 3.10 to 3.14. Docker images at `ghcr.io/clickhouse/mcp-clickhouse` since 0.4.0. chDB needs the extra, `pip install 'mcp-clickhouse[chdb]'`" }, { "label": "Transports", "value": "stdio (default), streamable HTTP (`CLICKHOUSE_MCP_SERVER_TRANSPORT=http`, endpoint `/mcp` on `127.0.0.1:8000`) and SSE, which is deprecated and logs a warning. `/health` is unauthenticated on HTTP and SSE" }, { "label": "Tools", "value": "`run_query` (`query`, optional `params`), `list_databases` (no inputs), `list_tables` (`database`, optional `like`, `not_like`, `page_token`, `page_size` default 50, `include_detailed_columns`). `run_chdb_select_query` (`query`) when chDB is enabled. Results are JSON-encoded strings" }, { "label": "Credentials", "value": "`CLICKHOUSE_HOST`, `CLICKHOUSE_USER` and `CLICKHOUSE_PASSWORD`, or a client certificate with `CLICKHOUSE_CLIENT_CERT` and `CLICKHOUSE_TLS_MODE` (mutual, proxy or strict). Optional `CLICKHOUSE_ROLE`. The connection uses ClickHouse's HTTP interface on 8443 or 8123, not the native protocol" }, { "label": "Restrictions", "value": "`readonly=1` by default. `CLICKHOUSE_ALLOW_WRITE_ACCESS=true` for DDL and inserts, plus `CLICKHOUSE_ALLOW_DROP=true` for destructive statements. With write access on and drop off, the server reads `SHOW GRANTS` once and logs a warning if the user holds destructive privileges" }, { "label": "HTTP protections", "value": "Authentication required by default. `CLICKHOUSE_MCP_ALLOWED_HOSTS` and `CLICKHOUSE_MCP_ALLOWED_ORIGINS` validate Host (421 on mismatch) and Origin (403). A wildcard bind refuses to start without an allowed-hosts list. `CLICKHOUSE_MCP_TRUSTED_PROXIES` for `X-Forwarded-Host`" }, { "label": "Limits", "value": "`CLICKHOUSE_MCP_QUERY_TIMEOUT` 30 seconds by default, after which the server attempts `KILL QUERY`. `CLICKHOUSE_MCP_MAX_WORKERS` 10. No row or byte limit on `run_query` results" }, { "label": "Usage statistics", "value": "No telemetry code was found in the 0.7.0 source. The server sends the client name `mcp_clickhouse` to the ClickHouse it connects to and logs each query's SQL text at INFO level" }, { "label": "Releases", "value": "0.1.0 on 24 December 2024. 0.3.0 on 14 April 2026 (write mode, tool renamed to `run_query`), 0.4.0 on 3 June, 0.4.1 on 17 July, 0.5.0 on 1 September, 0.6.0 on 3 September (FastMCP 4), 0.7.0 tagged 21 September 2026" } ], "provenance": { "legalEntity": "ClickHouse, Inc.", "domain": "clickhouse.com", "domainRegistered": "1999-03-12", "endpointOnVendorDomain": null, "terms": "", "privacy": "", "statusPage": "", "changelog": "https://github.com/ClickHouse/mcp-clickhouse/blob/main/CHANGELOG.md", "securityTxt": "valid", "checked": "2026-10-09", "notes": [ "No terms document governs this software beyond the Apache-2.0 licence, so `terms` is left out.", "`privacy` is left out. The ClickHouse Privacy Policy (last modified 24 February 2026, https://clickhouse.com/legal/privacy-policy) covers ClickHouse, Inc.'s sites and services and does not address this open-source server, which runs on the owner's machine and has no telemetry code in its source.", "clickhouse.com/.well-known/security.txt gives security@clickhouse.com, a policy link to the ClickHouse repository's SECURITY.md and an expiry of 28 July 2027.", "RDAP for clickhouse.com gives a registration date of 1999-03-12.", "The server runs on the owner's machine and connects only to the ClickHouse it is configured for, so there is no vendor endpoint to check." ], "score": 87, "checks": [ { "check": "Legal entity named", "value": "ClickHouse, Inc.", "points": 20, "max": 20, "state": "ok" }, { "check": "Domain age", "value": "clickhouse.com, registered 1999-03-12 (27 years)", "points": 15, "max": 15, "state": "ok" }, { "check": "Endpoint on the vendor's domain", "value": "no hosted endpoint", "points": 0, "max": 0, "state": "na" }, { "check": "Terms of service", "value": "nothing hosted, so the Apache-2.0 licence stands in", "points": 10, "max": 10, "state": "ok" }, { "check": "Privacy policy", "value": "nothing hosted, not scored", "points": 0, "max": 0, "state": "na" }, { "check": "Status page", "value": "not found", "points": 0, "max": 10, "state": "no" }, { "check": "Changelog", "value": "published", "points": 10, "max": 10, "state": "ok" }, { "check": "security.txt", "value": "valid", "points": 10, "max": 10, "state": "ok" } ] }, "pageJsonUrl": "https://www.anchorterminal.com/tools/clickhouse-mcp-server.json" } }