参数	环境变量	CLI 标志	必填	默认值
模式	`MYSQL_MODE`	`--mysql-mode`	是	—（`readonly` 或 `readwrite`）
主机	`MYSQL_HOST`	`--mysql-host`	是	—
端口	`MYSQL_PORT`	`--mysql-port`	否	`3306`
用户	`MYSQL_USER`	`--mysql-user`	是	—
密码	`MYSQL_PASSWORD`	`--mysql-password`	是	—
数据库	`MYSQL_DATABASE`	`--mysql-database`	是	—

如果缺少必需的值，或者 MYSQL_MODE 不是 readonly/readwrite，服务器会向 stderr 打印错误并以状态码 1 退出，不会启动。

readonly 模式：只允许 select 工具。insert/update/delete 会被以 PERMISSION_DENIED 错误拒绝。
readwrite 模式：允许所有四个工具。

模式在进程生命周期内固定不变；运行时无法更改。

安全建议：readonly 模式是应用层面的防护，不能替代数据库权限。如有可能，请让 readonly 模式指向一个仅拥有 SELECT 授权的 MySQL 账户。

是否需要 .env 文件？ 不需要。服务器本身从不读取 .env 文件——它只读取 CLI 标志和真实的进程环境变量（os.environ）。如何将值注入该环境取决于你如何运行它：
作为 MCP 服务器运行（参见从 MCP 客户端连接）：客户端（Claude Desktop/Code）会启动服务器进程，并将其自身 JSON 配置中的 env 块直接作为环境变量注入。不涉及也不需要 .env 文件。
直接运行 CLI 进行本地开发/测试：.env 只是为了方便你无需手动 export 六个变量。将 .env.example 复制为 .env，填写真实值，然后显式加载它——它不会被自动读取：
uv run --env-file .env mysql-mcp-server
.env 已被 git 忽略，绝不能提交。

运行

# Environment variables (or use `uv run --env-file .env mysql-mcp-server`, see above)
export MYSQL_MODE=readonly
export MYSQL_HOST=127.0.0.1
export MYSQL_PORT=3306
export MYSQL_USER=app_user
export MYSQL_PASSWORD=secret
export MYSQL_DATABASE=mydb
uv run mysql-mcp-server

# Or, equivalently, via CLI flags
uv run mysql-mcp-server \
  --mysql-mode readonly \
  --mysql-host 127.0.0.1 \
  --mysql-port 3306 \
  --mysql-user app_user \
  --mysql-password secret \
  --mysql-database mydb

从 MCP 客户端连接

Claude Desktop / Claude Code

在 MCP 客户端的服务器配置中添加一个条目（例如 Claude Desktop 的 claude_desktop_config.json，或 Claude Code 的 .mcp.json）：

{
  "mcpServers": {
    "mysql": {
      "command": "uv",
      "args": [
        "--directory",
        "/absolute/path/to/mysql-mcp-server",
        "run",
        "mysql-mcp-server"
      ],
      "env": {
        "MYSQL_MODE": "readonly",
        "MYSQL_HOST": "127.0.0.1",
        "MYSQL_PORT": "3306",
        "MYSQL_USER": "app_user",
        "MYSQL_PASSWORD": "secret",
        "MYSQL_DATABASE": "mydb"
      }
    }
  }
}

编辑配置后重启客户端。select、insert、update 和 delete 工具（受 MYSQL_MODE 约束）随后即可供模型使用。

工具

所有四个工具都接受 {"query": string, "params"?: array}，并且始终在 query 中使用 %s 参数绑定占位符——绝不要将用户输入以字符串格式化方式拼入查询。

工具	允许的模式	查询必须以什么开头	成功时的 `data` 形状
`select`	任意模式	`SELECT` / `WITH`	`{rows, row_count, truncated}`（最多 1000 行）
`insert`	仅 `readwrite`	`INSERT`	`{affected_rows, last_insert_id}`
`update`	仅 `readwrite`	`UPDATE`	`{affected_rows}`（若无 `WHERE` 则附带 `warning`）
`delete`	仅 `readwrite`	`DELETE`	`{affected_rows}`（若无 `WHERE` 则附带 `warning`）

每次工具调用都会返回以下之一：

{ "success": true, "data": { ... } }

{ "success": false, "error": { "code": "...", "message": "..." } }

错误码：PERMISSION_DENIED、INVALID_QUERY_TYPE、MULTI_STATEMENT_NOT_ALLOWED、 DB_CONNECTION_ERROR、DB_EXECUTION_ERROR、INTERNAL_ERROR。

多语句查询（以 ; 分隔）以及任何 DDL/权限语句（DROP、 TRUNCATE、ALTER、GRANT、CREATE USER 等）一律被拒绝，因为只有上述四种白名单语句类型会被接受。

开发

uv sync
uv run ruff format .
uv run ruff check .
uv run pytest -v
uv run uv build   # packaging check

故障排查

服务器以状态码 1 立即退出：缺少必需的 MYSQL_* 值，或者 MYSQL_MODE 无效——请检查 stderr 以确定具体原因。
DB_CONNECTION_ERROR：MySQL 无法访问，或凭据错误。服务器会继续运行，并在下一次工具调用时重试连接。
对 insert/update/delete 返回 PERMISSION_DENIED：服务器当前以 readonly 模式运行；如需写入操作，请以 MYSQL_MODE=readwrite 重启。

版本历史

0.1.0 — 初始版本：select/insert/update/delete 工具、readonly/ readwrite 模式策略、stdio MCP 传输、连接断开时自动重连并重试。

Available Tools

4 tools

deleteA

Execute a DELETE statement and return the affected row count. Only available when the server is running in 'readwrite' mode; rejected with PERMISSION_DENIED in 'readonly' mode. A DELETE with no WHERE clause is executed but flagged with a warning, since it removes every row in the table. Always use %s placeholders in query with values passed via params; never concatenate user-supplied values into query.

ParametersJSON Schema

Name	Required	Description	Default
`query`	Yes
`params`	No

Output Schema

ParametersJSON Schema

Name	Required	Description
No output parameters

TDQS

A4.8/5.0

Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries full burden. It discloses the readwrite/readonly mode behavior, the warning flag for DELETE without WHERE, and the security requirement to use placeholders. These are significant behavioral traits beyond what the schema shows.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is three sentences, each earning its place: core function, mode restriction, warning, and security guideline. No fluff or repetition.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a deletion tool with output schema present, the description covers the essential aspects: return value (row count), mode availability, dangerous no-WHERE behavior, and parameter usage. It is sufficiently complete for an agent to use correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters5/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description must explain both parameters. It does so by clarifying that `query` is a DELETE statement with %s placeholders and `params` provides values, plus warns against concatenation. This adds substantial meaning beyond the basic schema type definitions.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

Clearly states it executes a DELETE statement and returns the affected row count. This distinguishes it from sibling tools select, insert, and update by specifying the exact SQL operation.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explains the tool is only available in 'readwrite' mode and rejected with PERMISSION_DENIED in 'readonly' mode, providing clear context for when it can be used. Does not explicitly compare to alternatives, but the purpose and mode restrictions give sufficient guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

insertA

Execute an INSERT statement and return the affected row count and last insert id. Only available when the server is running in 'readwrite' mode; rejected with PERMISSION_DENIED in 'readonly' mode. Always use %s placeholders in query with values passed via params; never concatenate user-supplied values into query.

ParametersJSON Schema

Name	Required	Description	Default
`query`	Yes
`params`	No

Output Schema

ParametersJSON Schema

Name	Required	Description
No output parameters

TDQS

A4.1/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

While no annotations are provided, the description discloses key behavioral traits: the mode-dependent availability (PERMISSION_DENIED in readonly mode) and the return values (affected row count and last insert id). It also provides security guidance on parameterization, which is essential for agent behavior.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two sentences, front-loaded with the primary purpose, followed by mode restriction and security guidance. Every sentence earns its place; no filler or redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The tool has an output schema, which may explain return values, so the agent knows what to expect. The description covers the key semantics: the operation and parameterization. It gives clear guidance on mode requirements and security, which is sufficient for a tool with only two simple parameters and an output schema.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema has 0% description coverage, so the description must compensate. It does explain the purpose of `query` (the INSERT statement) and `params` (values for placeholders), but it doesn't detail the exact types or format expectations beyond mentioning placeholders. The baseline is 3 because the description adds some meaning but not fully.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool's purpose: to execute an INSERT statement and return the affected row count and last insert id. It distinguishes itself from siblings (select, update, delete) by naming the specific SQL operation, though it could explicitly contrast with siblings.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides explicit usage context: only available in 'readwrite' mode, and it warns against concatenating user-supplied values, instructing to use placeholders. It does not explicitly mention when not to use it (e.g., for other SQL operations), but the sibling names make that clear.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

selectA

Execute a read-only SELECT (or WITH ... SELECT) statement and return matching rows. Always available regardless of MYSQL_MODE. Always use %s placeholders in query with values passed via params; never concatenate user-supplied values into query.

ParametersJSON Schema

Name	Required	Description	Default
`query`	Yes
`params`	No

Output Schema

ParametersJSON Schema

Name	Required	Description
No output parameters

TDQS

A4.5/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries the full burden. It discloses the read-only safety profile, availability, and the critical placeholder requirement. It does not mention error behavior, transaction details, or return format, but the output schema covers return values. It adds meaningful context beyond what annotations would provide.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is three concise sentences, each adding value: purpose, availability, and security guideline. It is front-loaded with the core purpose and contains no redundant or filler content.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the simple tool (2 parameters, no nested objects, output schema present), the description covers purpose, read-only nature, availability, and placeholder usage. It is complete for a SELECT tool and the output schema handles return value documentation. No significant gaps remain.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description must compensate. It explains that `query` is a SQL statement with %s placeholders and that `params` holds the substitution values, clarifying the relationship between the two parameters. It does not enumerate all parameter types, but the schema is simple and the guidance is sufficient.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description explicitly states 'Execute a read-only SELECT (or WITH ... SELECT) statement and return matching rows,' which is a specific verb+resource+scope. It clearly distinguishes from the sibling tools insert, update, and delete by emphasizing the read-only nature.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides clear usage context: always available regardless of MYSQL_MODE, and the requirement to use %s placeholders with params rather than concatenating values. It implies this is for read queries while siblings are for writes, but does not explicitly name alternatives or exclusion scenarios.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

updateA

Execute an UPDATE statement and return the affected row count. Only available when the server is running in 'readwrite' mode; rejected with PERMISSION_DENIED in 'readonly' mode. An UPDATE with no WHERE clause is executed but flagged with a warning, since it affects every row in the table. Always use %s placeholders in query with values passed via params; never concatenate user-supplied values into query.

ParametersJSON Schema

Name	Required	Description	Default
`query`	Yes
`params`	No

Output Schema

ParametersJSON Schema

Name	Required	Description
No output parameters

TDQS

A4.8/5.0

Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description reveals several behavioral traits: returns affected row count, is rejected in readonly mode, warns when no WHERE clause (affects all rows), and enforces parameterized queries. These go beyond the schema and give a clear picture of the tool's behavior and side effects.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is compact yet information-dense, with each sentence serving a specific purpose: purpose, mode condition, warning, and security guideline. It is well-structured and front-loaded, with no redundant or filler content.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the operation, mode constraints, warning behavior, and security practice, the description covers all essential aspects for using the tool correctly. It specifies the return value (affected row count) and does not leave critical gaps; it is complete for the context of an UPDATE tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters5/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The description clarifies the meaning and relationship of the parameters: query is an UPDATE SQL statement, params are values for placeholders, and %s placeholders must be used. This adds significant semantic detail beyond the bare schema, which only lists query and params as types.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool executes an UPDATE statement and returns the affected row count, which is distinct from the sibling tools (select, insert, delete). The verb 'execute' and resource 'UPDATE statement' are specific and unambiguous.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides explicit conditions for usage—only in readwrite mode, with a warning for missing WHERE clause—and gives security guidance (use %s placeholders, never concatenate user-supplied values). However, it does not explicitly contrast with when to use insert or delete, so it stops short of complete alternative differentiation.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Tool Schema Changelog

Recent tool additions, removals, and schema changes observed during successful MCP inspections.

4 tool updatesv0.1.0Aug 21, 2026
- First observeddelete
- First observedinsert
- First observedselect
- First observedupdate

Deploy Server

Shareable, User-Owned Context BackendPeople, applications, and agents read, write, and coordinate together in one context lake. Reach it over MCP, a CLI, a Python SDK, or REST.fulcradynamics.comAd

TDQS

A4.6/5.0

Scored 2026-08-21 01:25 across 4 tools

Disambiguation5/5

Each tool maps to a distinct SQL operation (SELECT, INSERT, UPDATE, DELETE) with no functional overlap. Misselection is impossible because the actions are mutually exclusive.

Naming Consistency5/5

All tool names are single lowercase verbs that directly match their SQL counterparts, forming a perfectly consistent and predictable pattern.

Tool Count5/5

Four tools precisely cover the core CRUD operations for a database server without redundancy or excessive granularity, matching the expected scope.

Completeness5/5

The tool surface provides full coverage of data manipulation (create, read, update, delete) with no obvious gaps. Additional schema or transaction management is outside the stated read/write mode scope.

Maintenance

ActivitySlowing

ResponsivenessNo issues

Resources

GitHub Repository

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