bugfix

internal/mcp/tools_workspace.go

@@ -35,6 +35,7 @@ func registerWorkspaceTools(srv *mcpsdk.Server, deps ServerDeps) {
 	registerGitStatus(srv, deps)
 	registerGitCommit(srv, deps)
 	registerGitPush(srv, deps)
+	registerGitDiff(srv, deps)
 }
 
 // ===== 共用 DTO / helper =====
@@ -581,6 +582,59 @@ func registerGitCommit(srv *mcpsdk.Server, deps ServerDeps) {
 		})
 }
 
+// ===== git_diff (read-only) =====
+
+type gitDiffIn struct {
+	WorkspaceID  string   `json:"workspace_id" jsonschema:"workspace UUID"`
+	WorktreeID   string   `json:"worktree_id,omitempty" jsonschema:"optional worktree UUID; omit to target the main worktree"`
+	Ref          string   `json:"ref,omitempty" jsonschema:"base ref; empty diffs working tree against HEAD"`
+	Against      string   `json:"against,omitempty" jsonschema:"second ref; when set with ref produces ref..against"`
+	Staged       bool     `json:"staged,omitempty" jsonschema:"diff the staged index (--cached) instead of the working tree"`
+	Paths        []string `json:"paths,omitempty" jsonschema:"optional pathspecs to restrict the diff"`
+	ContextLines int      `json:"context_lines,omitempty" jsonschema:"unified context lines (git default 3 when omitted)"`
+}
+type gitDiffOut struct {
+	Diff      string `json:"diff"`
+	Truncated bool   `json:"truncated"`
+}
+
+func registerGitDiff(srv *mcpsdk.Server, deps ServerDeps) {
+	mcpsdk.AddTool(srv,
+		&mcpsdk.Tool{Name: "git_diff", Description: "Show the unified git diff of the main worktree or a branch worktree. Returns raw diff text (capped at 1 MiB)."},
+		func(ctx context.Context, _ *mcpsdk.CallToolRequest, in gitDiffIn) (*mcpsdk.CallToolResult, gitDiffOut, error) {
+			if err := CheckToolFromCtx(ctx, "git_diff"); err != nil {
+				return nil, gitDiffOut{}, err
+			}
+			c, err := deps.Caller.Resolve(ctx)
+			if err != nil {
+				return nil, gitDiffOut{}, err
+			}
+			w, wc, err := scopedWorkspace(ctx, deps, c, in.WorkspaceID)
+			if err != nil {
+				return nil, gitDiffOut{}, err
+			}
+			opts := git.DiffOptions{
+				Ref: in.Ref, Against: in.Against, Staged: in.Staged,
+				Paths: in.Paths, ContextLines: in.ContextLines,
+			}
+			var res git.DiffResult
+			if in.WorktreeID == "" {
+				res, err = deps.GitOps.DiffOnMain(ctx, wc, w.ID, opts)
+			} else {
+				var wt *workspace.Worktree
+				wt, err = worktreeInWorkspace(ctx, deps, wc, w.ID, in.WorktreeID)
+				if err != nil {
+					return nil, gitDiffOut{}, err
+				}
+				res, err = deps.GitOps.DiffOnWorktree(ctx, wc, wt.ID, opts)
+			}
+			if err != nil {
+				return nil, gitDiffOut{}, err
+			}
+			return nil, gitDiffOut{Diff: res.Diff, Truncated: res.Truncated}, nil
+		})
+}
+
 func registerGitPush(srv *mcpsdk.Server, deps ServerDeps) {
 	mcpsdk.AddTool(srv,
 		&mcpsdk.Tool{Name: "git_push", Description: "Push the main worktree or a branch worktree to the remote."},