simplecov mcp
允许Claude直接访问SimpleCov覆盖率报告的MCP服务器。
无需通读全文 coverage/.resultset.json （可以是数十MB）。通过工具只检索您需要的数据。
设置
git clone https://github.com/yourname/simplecov-mcp.git
cd simplecov-mcp
pnpm install && pnpm build然后，在Rails项目根目录中注册MCP服务器：
claude mcp add simplecov node /path/to/simplecov-mcp/build/index.js这将MCP服务器添加到项目的 .mcp.json服务器自动检测 coverage/ 从工作目录中选择目录。
要明确指定覆盖路径，请执行以下操作：
claude mcp add simplecov -e SIMPLECOV_COVERAGE_PATH=/path/to/coverage node /path/to/simplecov-mcp/build/index.js添加后，重新启动Claude Code并用验证 /mcp.
工具
get_summary
返回总体覆盖率摘要。
> get_summary
{
"lastRun": { "line": 100, "branch": 100 },
"totalFiles": 1669,
"computed": { "lineCoverage": 53.56, "branchCoverage": 48.07 }
}list_files
列出文件及其覆盖率。支持排序和过滤。
| 参数 | 类型 | 默认值 | 说明 | |||
|---|---|---|---|---|---|---|
sort_by | path | line_coverage | branch_coverage | missed_lines | path | 排序键 |
order | asc | desc | asc | 排序顺序 | ||
min_coverage | number | - | 最低覆盖率 | |||
max_coverage | number | - | 最大覆盖百分比 | |||
path_pattern | string | - | 文件路径的部分匹配筛选器 |
> list_files sort_by=missed_lines order=desc max_coverage=50
[
{ "file": ".../inquiries_controller.rb", "line": "8.96% (37/413)", "missed": 376 },
...
]get_file_coverage
返回特定文件的详细覆盖率，包括每行命中次数、未覆盖的行号和分支覆盖率。
| 参数 | 类型 | 说明 |
|---|---|---|
file_path | string（必填） | 文件路径。按后缀匹配 |
> get_file_coverage file_path=app/models/user.rb
{
"filePath": "/usr/src/app/app/models/user.rb",
"lineCoverage": "85.71% (12/14)",
"uncoveredLineNumbers": [42, 43],
"lines": [...],
"branches": [...]
}get_uncovered_lines
仅提取未覆盖的线条和分支。在添加测试时很有用。
> get_uncovered_lines file_path=app/services/order_service.rb
{
"filePath": "/usr/src/app/app/services/order_service.rb",
"lineCoverage": "72.5%",
"uncoveredLineNumbers": [15, 16, 42, 43, 44],
"uncoveredBranches": [
{ "condition": "[:if, 3, 15, 6, 15, 40]", "branch": "[:else, 5, 15, 6, 15, 40]" }
]
}estimate_file_coverage
估计代码更改后的覆盖率，而无需重新运行测试。将服务器启动时保存的文件（基线）与磁盘上的当前文件进行比较，并通过行级差异映射旧的覆盖率数据。
| 参数 | 类型 | 说明 |
|---|---|---|
file_path | string（必填） | 文件路径。按后缀匹配 |
> estimate_file_coverage file_path=app/models/user.rb
{
"filePath": "/usr/src/app/app/models/user.rb",
"fileChanged": true,
"originalCoverage": "85.71% (12/14)",
"estimatedCoverage": "82.35% (14/17)",
"changeSummary": { "unchanged": 45, "added": 5, "removed": 2, "modified": 3 },
"estimatedNewLines": [
{ "line": 15, "type": "modified", "status": "covered", "confidence": "medium" },
{ "line": 22, "type": "added", "status": "likely_covered", "confidence": "low" }
],
"estimatedUncoveredLineNumbers": [30, 42, 43],
"note": "..."
}估算逻辑：
| 线型 | 方法 | 置信度 |
|---|---|---|
| 不变 | 按原样使用原始覆盖率 | 高 |
| modified | 继承原始覆盖率（测试可能仍然到达线路） | 中等 |
| 已添加 | 来自周围街区覆盖率的估计值 | 低 |
此工具专为代理编码工作流而设计：运行一次测试，进行改进，估计覆盖率影响，然后继续前进。
Claude使用示例
"Show me files with low coverage"
"Show uncovered lines in app/models/user.rb"
"List controllers with coverage below 50%"
"Write tests for the uncovered lines in this file"
"Estimate coverage after my changes to user.rb"运作原理
Rails Project
├── coverage/
│ ├── .resultset.json ← Generated by SimpleCov (tens of MB)
│ └── .last_run.json ← Summary
└── .mcp.json ← MCP configuration (created by claude mcp add)
simplecov-mcp searches for the coverage/ directory starting from cwd,
then walking up to parent directories. It parses .resultset.json and
holds the data in memory. Claude retrieves only the needed portions
via tools.
At startup, the server also reads and caches the source files referenced
in coverage data. This baseline is used by estimate_file_coverage to
detect changes and map coverage through line-level diffs (LCS-based).