feat: add standard MCP tool support by lizhengfeng101 · Pull Request #212 · alibaba/open-code-review

lizhengfeng101 · 2026-06-24T12:38:47Z

Summary

This PR introduces standard MCP (Model Context Protocol) tool support for OpenCodeReview, enabling extensible context capabilities for the review agent.

Add MCP tool integration framework with standard protocol support
CodeGraph will likely be the first built-in MCP extension, providing structural code analysis (symbol definitions, callers, callees, impact radius)

🚧 Work in Progress — implementation is under evaluation.

Closes #210

github-actions · 2026-06-24T12:39:00Z

✅ OpenCodeReview: No supported files changed.

Add MCP client and provider packages that allow integrating external MCP tool servers into the review loop. Includes config commands for managing MCP servers, stdio subprocess integration tests, and comprehensive test coverage.

…ng Client receiver

The MCP server setup command was hardcoded to use `sh -c`, which fails on Windows. Extract a `shellCommand` helper behind build tags to use `cmd /c` on Windows and `sh -c` elsewhere.

Copilot

Pull request overview

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Adds MCP (Model Context Protocol) stdio-based tool integration so OpenCodeReview can discover/register external tools and execute them in the review loop, with corresponding CLI config and documentation updates.

Changes:

Introduces an internal/mcp client/provider layer (connect, list tools, call tools, register into tool registry).
Extends tool definitions with reserved-name detection and dynamic tool creation.
Adds CLI config support for mcp_servers.* plus README updates across multiple languages.

Reviewed changes

Copilot reviewed 22 out of 23 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
internal/tool/definitions.go	Adds reserved-name check and dynamic tool factory for MCP-discovered tools.
internal/tool/definitions_test.go	Adds tests for reserved-name detection and dynamic tool creation constraints.
internal/mcp/client.go	Adds MCP stdio client wrapper (connect, list tools, call tools).
internal/mcp/client_test.go	Adds unit/integration tests for client behavior and content rendering.
internal/mcp/provider.go	Adds MCP tool Provider adapter, tool registration, and tooldef collection.
internal/mcp/provider_test.go	Adds tests for MCP provider registration/filtering and tooldef conversion.
internal/mcp/stdio_test.go	Adds subprocess-backed stdio transport integration test.
internal/llmloop/loop.go	Enables executing dynamically-registered tools via the tool registry.
cmd/opencodereview/review_cmd.go	Initializes MCP clients from config, registers tools, and adds tool defs to agent.
cmd/opencodereview/shell_unix.go	Adds `sh -c` helper for running MCP setup commands on Unix.
cmd/opencodereview/shell_windows.go	Adds `cmd /c` helper for running MCP setup commands on Windows.
cmd/opencodereview/procattr_unix.go	Adds process-group handling to better kill setup command subprocess trees on Unix.
cmd/opencodereview/procattr_windows.go	Documents Windows limitation for process-tree cleanup.
cmd/opencodereview/config_cmd.go	Adds `mcp_servers` config schema, set/unset support, and config validation logic.
cmd/opencodereview/config_cmd_test.go	Adds tests for MCP server config set/unset behavior and validation.
cmd/opencodereview/flags.go	Updates CLI help text for MCP server config keys.
go.mod	Adds MCP SDK dependency and bumps Go version directive.
go.sum	Updates sums for new/updated dependencies.
README.md	Documents MCP server config keys and usage.
README.ja-JP.md	Documents MCP server config keys and usage (Japanese).
README.ko-KR.md	Documents MCP server config keys and usage (Korean).
README.ru-RU.md	Documents MCP server config keys and usage (Russian).
README.zh-CN.md	Documents MCP server config keys and usage (Chinese).

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+	if result.IsError {
+		return fmt.Sprintf("MCP tool %q returned an error: %s", name, contentToText(result.Content)), nil
+	}


+	transport := &mcp.CommandTransport{Command: cmd}
+	session, err := client.Connect(ctx, transport, nil)
+	if err != nil {
+		return nil, fmt.Errorf("connect to MCP server %q: %w", name, err)
+	}


+	for _, t := range c.Tools() {
+		if filtering {
+			if _, ok := allowed[t.Name]; !ok {
+				continue
+			}
+			matched[t.Name] = struct{}{}
+		}
+		if tool.IsReserved(t.Name) {
+			fmt.Fprintf(os.Stderr, "[ocr] WARNING: MCP server %q tool %q conflicts with built-in tool, skipping\n", c.Name(), t.Name)
+			continue
+		}


+	if err != nil {
+		t.Fatalf("NewClient: %v", err)
+	}
+	defer c.Close()


+	if err := c.Close(); err != nil {
+		t.Errorf("Close: %v", err)
+	}


+	}
+
+	c := &Client{name: "test-srv", session: session, tools: toolsResult.Tools}
+	defer c.Close()


+	t.Run("Close", func(t *testing.T) {
+		if err := c.Close(); err != nil {
+			t.Errorf("Close: %v", err)
+		}
+	})


lizhengfeng101 · 2026-07-01T09:16:14Z

已处理 Copilot 提出的全部 7 条评审建议，修复提交：56b9d54

错误处理（2 条）

✅ client.go:80 — CallTool 在 IsError=true 时现在返回非 nil error，调用方和遥测能正确识别工具失败
✅ client.go:41 — Connect 失败时显式 kill 已启动的子进程，防止孤儿进程泄漏

健壮性（1 条）

✅ provider.go:48 — RegisterAll 增加空工具名防护，跳过并打印警告，避免后续 tool.Dynamic("") panic

测试 double-close（4 条）

✅ stdio_test.go:71,98 + client_test.go:116,229 — 移除多余的 defer c.Close()，保留显式 close 断言，避免 double-close 导致的 flaky 行为

lizhengfeng101 · 2026-07-01T09:16:52Z

已处理 Copilot 提出的全部 7 条评审建议，修复提交：56b9d54

错误处理（2 条）

✅ client.go:80 — CallTool 在 IsError=true 时现在返回非 nil error，调用方和遥测能正确识别工具失败

✅ client.go:41 — Connect 失败时显式 kill 已启动的子进程，防止孤儿进程泄漏

健壮性（1 条）

✅ provider.go:48 — RegisterAll 增加空工具名防护，跳过并打印警告，避免后续 tool.Dynamic("") panic

测试 double-close（4 条）

✅ stdio_test.go:71,98 + client_test.go:116,229 — 移除多余的 defer c.Close()，保留显式 close 断言，避免 double-close 导致的 flaky 行为

@MuoDoo

Copilot

Pull request overview

Copilot reviewed 22 out of 23 changed files in this pull request and generated 8 comments.

+	if result.IsError {
+		return fmt.Sprintf("MCP tool %q returned an error: %s", name, contentToText(result.Content)), nil
+	}


+	params := map[string]any{"type": "object"}
+
+	switch schema := t.InputSchema.(type) {
+	case map[string]any:
+		for k, v := range schema {
+			params[k] = v
+		}
+		if _, ok := params["type"]; !ok {
+			params["type"] = "object"
+		}


+	if err != nil {
+		t.Fatalf("NewClient: %v", err)
+	}
+	defer c.Close()


+	if err := c.Close(); err != nil {
+		t.Errorf("Close: %v", err)
+	}


+		session: session,
+		tools:   toolsResult.Tools,
+	}
+	defer c.Close()


+	t.Run("Close", func(t *testing.T) {
+		if err := c.Close(); err != nil {
+			t.Errorf("Close: %v", err)
+		}
+	})


 module github.com/open-code-review/open-code-review

-go 1.25.0
+go 1.25.5


+		if serverCfg.Setup != "" {
+			fmt.Fprintf(os.Stderr, "[ocr] Running setup for MCP server %q: %s\n", name, serverCfg.Setup)
+			setupCtx, setupCancel := context.WithTimeout(ctx, 5*time.Minute)
+			setupCmd := shellCommand(setupCtx, serverCfg.Setup)
+			setupCmd.Dir = repoDir
+			configureProcessGroup(setupCmd)
+			output, err := setupCmd.CombinedOutput()
+			setupCancel()


MuoDoo

LGTM.

GenjiCy mentioned this pull request Jun 24, 2026

Add optional CodeGraph structural context tool #210

Closed

lizhengfeng101 force-pushed the feat/mcp-support branch from d1ffbc4 to 4ffc7f1 Compare July 1, 2026 05:16

lizhengfeng101 marked this pull request as ready for review July 1, 2026 05:25

lizhengfeng101 force-pushed the feat/mcp-support branch from 4ffc7f1 to fc0c332 Compare July 1, 2026 06:33

feat(mcp): add Model Context Protocol server support

6c9ae5f

Add MCP client and provider packages that allow integrating external MCP tool servers into the review loop. Includes config commands for managing MCP servers, stdio subprocess integration tests, and comprehensive test coverage.

lizhengfeng101 force-pushed the feat/mcp-support branch from fc0c332 to 6c9ae5f Compare July 1, 2026 07:11

lizhengfeng101 changed the title ~~[WIP] feat: add standard MCP tool support~~ feat: add standard MCP tool support Jul 1, 2026

lizhengfeng101 added 3 commits July 1, 2026 15:38

refactor(mcp): rename loop variable in contentToText to avoid shadowi…

840acb3

…ng Client receiver

fix(mcp): use platform-specific shell for setup command

5f4f084

The MCP server setup command was hardcoded to use `sh -c`, which fails on Windows. Extract a `shellCommand` helper behind build tags to use `cmd /c` on Windows and `sh -c` elsewhere.

docs(mcp): add MCP server documentation to all README locales

6bf7e70

MuoDoo requested a review from Copilot July 1, 2026 08:27

lizhengfeng101 requested review from MuoDoo and css521 July 1, 2026 08:33

Copilot AI reviewed Jul 1, 2026

View reviewed changes

MuoDoo requested a review from Copilot July 1, 2026 09:48

Copilot AI reviewed Jul 1, 2026

View reviewed changes

MuoDoo approved these changes Jul 1, 2026

View reviewed changes

lizhengfeng101 merged commit 6adcb1e into main Jul 1, 2026
7 checks passed

lizhengfeng101 deleted the feat/mcp-support branch July 1, 2026 11:10

Copilot started reviewing on behalf of MuoDoo July 1, 2026 20:59 View session

Copilot started reviewing on behalf of MuoDoo July 1, 2026 22:34 View session

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feat: add standard MCP tool support#212

feat: add standard MCP tool support#212
lizhengfeng101 merged 4 commits into
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错误处理（2 条）

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测试 double-close（4 条）

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lizhengfeng101 commented Jun 24, 2026

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lizhengfeng101 commented Jul 1, 2026

错误处理（2 条）

健壮性（1 条）

测试 double-close（4 条）

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lizhengfeng101 commented Jul 1, 2026

错误处理（2 条）

健壮性（1 条）

测试 double-close（4 条）

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