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mcp: use StructuredContent; fix "path is empty" error #4119

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Merged
merged 2 commits into from
Oct 2, 2025
Merged

mcp: use StructuredContent; fix "path is empty" error #4119

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e5cc00f
mcp: use StructuredContent
AkihiroSuda Oct 1, 2025
9e735aa
mcp: search_file_content: fix "path is empty" error
AkihiroSuda Oct 1, 2025
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16 changes: 16 additions & 0 deletions pkg/mcp/msi/filesystem.go
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Original file line number Diff line number Diff line change
Expand Up @@ -42,6 +42,10 @@ var ReadFile = &mcp.Tool{
Description: `Reads and returns the content of a specified file.`,
}

type ReadFileResult struct {
Content string `json:"content" jsonschema:"The content of the file."`
}

type ReadFileParams struct {
Path string `json:"path" jsonschema:"The absolute path to the file to read."`
// TODO: Offset *int `json:"offset,omitempty" jsonschema:"For text files, the 0-based line number to start reading from. Requires limit to be set."`
Expand All @@ -53,6 +57,10 @@ var WriteFile = &mcp.Tool{
Description: `Writes content to a specified file. If the file exists, it will be overwritten. If the file doesn't exist, it (and any necessary parent directories) will be created.`,
}

type WriteFileResult struct {
// Empty for now
}

type WriteFileParams struct {
Path string `json:"path" jsonschema:"The absolute path to the file to write to."`
Content string `json:"content" jsonschema:"The content to write into the file."`
Expand All @@ -69,6 +77,10 @@ type GlobParams struct {
// TODO: CaseSensitive bool `json:"case_sensitive,omitempty" jsonschema:": Whether the search should be case-sensitive. Defaults to false."`
}

type GlobResult struct {
Matches []string `json:"matches" jsonschema:"A list of absolute file paths that match the provided glob pattern."`
}

var SearchFileContent = &mcp.Tool{
Name: "search_file_content",
Description: `Searches for a regular expression pattern within the content of files in a specified directory. Internally calls 'git grep -n --no-index'.`,
Expand All @@ -80,4 +92,8 @@ type SearchFileContentParams struct {
Include *string `json:"include,omitempty" jsonschema:"A glob pattern to filter which files are searched (e.g., '*.js', 'src/**/*.{ts,tsx}'). If omitted, searches most files (respecting common ignores)."`
}

type SearchFileContentResult struct {
GitGrepOutput string `json:"git_grep_output" jsonschema:"The raw output from the 'git grep -n --no-index' command, containing matching lines with filenames and line numbers."`
}

// TODO: implement Replace
58 changes: 34 additions & 24 deletions pkg/mcp/toolset/filesystem.go
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Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,6 @@ package toolset

import (
"context"
"encoding/json"
"errors"
"io"
"os"
Expand All @@ -19,7 +18,7 @@ import (

func (ts *ToolSet) ListDirectory(ctx context.Context,
_ *mcp.CallToolRequest, args msi.ListDirectoryParams,
) (*mcp.CallToolResult, any, error) {
) (*mcp.CallToolResult, *msi.ListDirectoryResult, error) {
if ts.inst == nil {
return nil, nil, errors.New("instance not registered")
}
Expand All @@ -31,7 +30,7 @@ func (ts *ToolSet) ListDirectory(ctx context.Context,
if err != nil {
return nil, nil, err
}
res := msi.ListDirectoryResult{
res := &msi.ListDirectoryResult{
Entries: make([]msi.ListDirectoryResultEntry, len(guestEnts)),
}
for i, f := range guestEnts {
Expand All @@ -41,18 +40,14 @@ func (ts *ToolSet) ListDirectory(ctx context.Context,
res.Entries[i].ModTime = ptr.Of(f.ModTime())
res.Entries[i].IsDir = ptr.Of(f.IsDir())
}
resJ, err := json.Marshal(res)
if err != nil {
return nil, nil, err
}
return &mcp.CallToolResult{
Content: []mcp.Content{&mcp.TextContent{Text: string(resJ)}},
}, nil, nil
StructuredContent: res,
}, res, nil
}

func (ts *ToolSet) ReadFile(_ context.Context,
_ *mcp.CallToolRequest, args msi.ReadFileParams,
) (*mcp.CallToolResult, any, error) {
) (*mcp.CallToolResult, *msi.ReadFileResult, error) {
if ts.inst == nil {
return nil, nil, errors.New("instance not registered")
}
Expand All @@ -71,17 +66,20 @@ func (ts *ToolSet) ReadFile(_ context.Context,
if err != nil {
return nil, nil, err
}
res := &msi.ReadFileResult{
Content: string(b),
}
return &mcp.CallToolResult{
// Gemini:
// For text files: The file content, potentially prefixed with a truncation message
// (e.g., [File content truncated: showing lines 1-100 of 500 total lines...]\nActual file content...).
Content: []mcp.Content{&mcp.TextContent{Text: string(b)}},
}, nil, nil
StructuredContent: res,
}, res, nil
}

func (ts *ToolSet) WriteFile(_ context.Context,
_ *mcp.CallToolRequest, args msi.WriteFileParams,
) (*mcp.CallToolResult, any, error) {
) (*mcp.CallToolResult, *msi.WriteFileResult, error) {
if ts.inst == nil {
return nil, nil, errors.New("instance not registered")
}
Expand All @@ -98,17 +96,18 @@ func (ts *ToolSet) WriteFile(_ context.Context,
if err != nil {
return nil, nil, err
}
res := &msi.WriteFileResult{}
return &mcp.CallToolResult{
// Gemini:
// A success message, e.g., `Successfully overwrote file: /path/to/your/file.txt`
// or `Successfully created and wrote to new file: /path/to/new/file.txt.`
Content: []mcp.Content{&mcp.TextContent{Text: "OK"}},
}, nil, nil
StructuredContent: res,
}, res, nil
}

func (ts *ToolSet) Glob(_ context.Context,
_ *mcp.CallToolRequest, args msi.GlobParams,
) (*mcp.CallToolResult, any, error) {
) (*mcp.CallToolResult, *msi.GlobResult, error) {
if ts.inst == nil {
return nil, nil, errors.New("instance not registered")
}
Expand All @@ -128,20 +127,19 @@ func (ts *ToolSet) Glob(_ context.Context,
if err != nil {
return nil, nil, err
}
resJ, err := json.Marshal(matches)
if err != nil {
return nil, nil, err
res := &msi.GlobResult{
Matches: matches,
}
return &mcp.CallToolResult{
// Gemini:
// A message like: Found 5 file(s) matching "*.ts" within src, sorted by modification time (newest first):\nsrc/file1.ts\nsrc/subdir/file2.ts...
Content: []mcp.Content{&mcp.TextContent{Text: string(resJ)}},
}, nil, nil
StructuredContent: res,
}, res, nil
}

func (ts *ToolSet) SearchFileContent(ctx context.Context,
req *mcp.CallToolRequest, args msi.SearchFileContentParams,
) (*mcp.CallToolResult, any, error) {
) (*mcp.CallToolResult, *msi.SearchFileContentResult, error) {
if ts.inst == nil {
return nil, nil, errors.New("instance not registered")
}
Expand All @@ -159,7 +157,19 @@ func (ts *ToolSet) SearchFileContent(ctx context.Context,
if args.Include != nil && *args.Include != "" {
guestPath = path.Join(guestPath, *args.Include)
}
return ts.RunShellCommand(ctx, req, msi.RunShellCommandParams{
Command: []string{"git", "grep", "-n", "--no-index", args.Pattern, guestPath},
cmdToolRes, cmdRes, err := ts.RunShellCommand(ctx, req, msi.RunShellCommandParams{
Command: []string{"git", "grep", "-n", "--no-index", args.Pattern, guestPath},
Directory: pathStr, // Directory must be always set
})
if err != nil {
return cmdToolRes, nil, err
}
res := &msi.SearchFileContentResult{
GitGrepOutput: cmdRes.Stdout,
}
return &mcp.CallToolResult{
// Gemini:
// A message like: Found 10 matching lines for regex "function\\s+myFunction" in directory src:\nsrc/file1.js:10:function myFunction() {...}\nsrc/subdir/file2.ts:45: function myFunction(param) {...}...
StructuredContent: res,
}, res, nil
}
13 changes: 4 additions & 9 deletions pkg/mcp/toolset/shell.go
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Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,6 @@ package toolset
import (
"bytes"
"context"
"encoding/json"
"errors"
"os/exec"

Expand All @@ -18,7 +17,7 @@ import (

func (ts *ToolSet) RunShellCommand(ctx context.Context,
_ *mcp.CallToolRequest, args msi.RunShellCommandParams,
) (*mcp.CallToolResult, any, error) {
) (*mcp.CallToolResult, *msi.RunShellCommandResult, error) {
if ts.inst == nil {
return nil, nil, errors.New("instance not registered")
}
Expand All @@ -33,7 +32,7 @@ func (ts *ToolSet) RunShellCommand(ctx context.Context,
cmd.Stdout = &stdout
cmd.Stderr = &stderr
cmdErr := cmd.Run()
res := msi.RunShellCommandResult{
res := &msi.RunShellCommandResult{
Stdout: stdout.String(),
Stderr: stderr.String(),
}
Expand All @@ -45,11 +44,7 @@ func (ts *ToolSet) RunShellCommand(ctx context.Context,
res.ExitCode = ptr.Of(st.ExitCode())
}
}
resJ, err := json.Marshal(res)
if err != nil {
return nil, nil, err
}
return &mcp.CallToolResult{
Content: []mcp.Content{&mcp.TextContent{Text: string(resJ)}},
}, nil, nil
StructuredContent: res,
}, res, nil
}