Optimize token usage in default list_ tools

pkg/github/issues.go

@@ -11,6 +11,7 @@ import (
 
 	ghErrors "github.com/github/github-mcp-server/pkg/errors"
 	"github.com/github/github-mcp-server/pkg/inventory"
+	"github.com/github/github-mcp-server/pkg/response"
 	"github.com/github/github-mcp-server/pkg/sanitize"
 	"github.com/github/github-mcp-server/pkg/scopes"
 	"github.com/github/github-mcp-server/pkg/translations"
@@ -1603,9 +1604,21 @@ func ListIssues(t translations.TranslationHelperFunc) inventory.ServerTool {
 				totalCount = fragment.TotalCount
 			}
 
-			// Create response with issues
-			response := map[string]any{
-				"issues": issues,
+			minimalIssues := make([]MinimalIssue, 0, len(issues))
+			for _, issue := range issues {
+				if issue != nil {
+					minimalIssues = append(minimalIssues, convertToMinimalIssue(issue))
+				}
+			}
+
+			optimizedIssues, err := response.OptimizeList(minimalIssues)
+			if err != nil {
+				return utils.NewToolResultErrorFromErr("failed to marshal response", err), nil, nil
+			}
+
+			// Wrap optimized issues with pagination metadata
+			issueResponse := map[string]any{
+				"issues": json.RawMessage(optimizedIssues),
 				"pageInfo": map[string]any{
 					"hasNextPage":     pageInfo.HasNextPage,
 					"hasPreviousPage": pageInfo.HasPreviousPage,
@@ -1614,7 +1627,7 @@ func ListIssues(t translations.TranslationHelperFunc) inventory.ServerTool {
 				},
 				"totalCount": totalCount,
 			}
-			out, err := json.Marshal(response)
+			out, err := json.Marshal(issueResponse)
 			if err != nil {
 				return nil, nil, fmt.Errorf("failed to marshal issues: %w", err)
 			}

pkg/github/issues_test.go

@@ -1187,7 +1187,6 @@ func Test_ListIssues(t *testing.T) {
 		expectError   bool
 		errContains   string
 		expectedCount int
-		verifyOrder   func(t *testing.T, issues []*github.Issue)
 	}{
 		{
 			name: "list all issues",
@@ -1295,32 +1294,29 @@ func Test_ListIssues(t *testing.T) {
 			}
 			require.NoError(t, err)
 
-			// Parse the structured response with pagination info
-			var response struct {
-				Issues   []*github.Issue `json:"issues"`
-				PageInfo struct {
-					HasNextPage     bool   `json:"hasNextPage"`
-					HasPreviousPage bool   `json:"hasPreviousPage"`
-					StartCursor     string `json:"startCursor"`
-					EndCursor       string `json:"endCursor"`
-				} `json:"pageInfo"`
-				TotalCount int `json:"totalCount"`
-			}
+			// Parse the response
+			var response map[string]any
 			err = json.Unmarshal([]byte(text), &response)
 			require.NoError(t, err)
 
-			assert.Len(t, response.Issues, tc.expectedCount, "Expected %d issues, got %d", tc.expectedCount, len(response.Issues))
+			// Metadata should be preserved
+			assert.NotNil(t, response["totalCount"])
+			pageInfo, ok := response["pageInfo"].(map[string]any)
+			require.True(t, ok, "pageInfo should be a map")
+			assert.Contains(t, pageInfo, "hasNextPage")
+			assert.Contains(t, pageInfo, "endCursor")
 
-			// Verify order if verifyOrder function is provided
-			if tc.verifyOrder != nil {
-				tc.verifyOrder(t, response.Issues)
-			}
+			issues, ok := response["issues"].([]any)
+			require.True(t, ok)
+			assert.Len(t, issues, tc.expectedCount, "Expected %d issues, got %d", tc.expectedCount, len(issues))
 
 			// Verify that returned issues have expected structure
-			for _, issue := range response.Issues {
-				assert.NotNil(t, issue.Number, "Issue should have number")
-				assert.NotNil(t, issue.Title, "Issue should have title")
-				assert.NotNil(t, issue.State, "Issue should have state")
+			for _, issue := range issues {
+				m, ok := issue.(map[string]any)
+				require.True(t, ok)
+				assert.NotNil(t, m["number"], "Issue should have number")
+				assert.NotNil(t, m["title"], "Issue should have title")
+				assert.NotNil(t, m["state"], "Issue should have state")
 			}
 		})
 	}

pkg/github/minimal_types.go

@@ -122,6 +122,12 @@ type MinimalBranch struct {
 	Protected bool   `json:"protected"`
 }
 
+// MinimalTag is the trimmed output type for tag objects.
+type MinimalTag struct {
+	Name string `json:"name"`
+	SHA  string `json:"sha"`
+}
+
 // MinimalResponse represents a minimal response for all CRUD operations.
 // Success is implicit in the HTTP response status, and all other information
 // can be derived from the URL or fetched separately if needed.
@@ -702,6 +708,37 @@ func convertToMinimalBranch(branch *github.Branch) MinimalBranch {
 	}
 }
 
+func convertToMinimalRelease(release *github.RepositoryRelease) MinimalRelease {
+	m := MinimalRelease{
+		ID:         release.GetID(),
+		TagName:    release.GetTagName(),
+		Name:       release.GetName(),
+		Body:       release.GetBody(),
+		HTMLURL:    release.GetHTMLURL(),
+		Prerelease: release.GetPrerelease(),
+		Draft:      release.GetDraft(),
+		Author:     convertToMinimalUser(release.GetAuthor()),
+	}
+
+	if release.PublishedAt != nil {
+		m.PublishedAt = release.PublishedAt.Format(time.RFC3339)
+	}
+
+	return m
+}
+
+func convertToMinimalTag(tag *github.RepositoryTag) MinimalTag {
+	m := MinimalTag{
+		Name: tag.GetName(),
+	}
+
+	if commit := tag.GetCommit(); commit != nil {
+		m.SHA = commit.GetSHA()
+	}
+
+	return m
+}
+
 func convertToMinimalReviewThreadsResponse(query reviewThreadsQuery) MinimalReviewThreadsResponse {
 	threads := query.Repository.PullRequest.ReviewThreads
 

pkg/github/pullrequests.go

@@ -16,6 +16,7 @@ import (
 	ghErrors "github.com/github/github-mcp-server/pkg/errors"
 	"github.com/github/github-mcp-server/pkg/inventory"
 	"github.com/github/github-mcp-server/pkg/octicons"
+	"github.com/github/github-mcp-server/pkg/response"
 	"github.com/github/github-mcp-server/pkg/sanitize"
 	"github.com/github/github-mcp-server/pkg/scopes"
 	"github.com/github/github-mcp-server/pkg/translations"
@@ -1148,7 +1149,16 @@ func ListPullRequests(t translations.TranslationHelperFunc) inventory.ServerTool
 				}
 			}
 
-			r, err := json.Marshal(prs)
+			minimalPRs := make([]MinimalPullRequest, 0, len(prs))
+			for _, pr := range prs {
+				if pr != nil {
+					minimalPRs = append(minimalPRs, convertToMinimalPullRequest(pr))
+				}
+			}
+
+			r, err := response.OptimizeList(minimalPRs,
+				response.WithPreservedFields("html_url", "draft"),
+			)
 			if err != nil {
 				return utils.NewToolResultErrorFromErr("failed to marshal response", err), nil, nil
 			}

pkg/github/repositories.go

@@ -13,6 +13,7 @@ import (
 	ghErrors "github.com/github/github-mcp-server/pkg/errors"
 	"github.com/github/github-mcp-server/pkg/inventory"
 	"github.com/github/github-mcp-server/pkg/octicons"
+	"github.com/github/github-mcp-server/pkg/response"
 	"github.com/github/github-mcp-server/pkg/scopes"
 	"github.com/github/github-mcp-server/pkg/translations"
 	"github.com/github/github-mcp-server/pkg/utils"
@@ -216,7 +217,10 @@ func ListCommits(t translations.TranslationHelperFunc) inventory.ServerTool {
 				minimalCommits[i] = convertToMinimalCommit(commit, false)
 			}
 
-			r, err := json.Marshal(minimalCommits)
+			r, err := response.OptimizeList(minimalCommits,
+				response.WithMaxDepth(3),
+				response.WithPreservedFields("html_url"),
+			)
 			if err != nil {
 				return nil, nil, fmt.Errorf("failed to marshal response: %w", err)
 			}
@@ -303,7 +307,9 @@ func ListBranches(t translations.TranslationHelperFunc) inventory.ServerTool {
 				minimalBranches = append(minimalBranches, convertToMinimalBranch(branch))
 			}
 
-			r, err := json.Marshal(minimalBranches)
+			r, err := response.OptimizeList(minimalBranches,
+				response.WithPreservedFields("protected"),
+			)
 			if err != nil {
 				return nil, nil, fmt.Errorf("failed to marshal response: %w", err)
 			}
@@ -1497,7 +1503,14 @@ func ListTags(t translations.TranslationHelperFunc) inventory.ServerTool {
 				return ghErrors.NewGitHubAPIStatusErrorResponse(ctx, "failed to list tags", resp, body), nil, nil
 			}
 
-			r, err := json.Marshal(tags)
+			minimalTags := make([]MinimalTag, 0, len(tags))
+			for _, tag := range tags {
+				if tag != nil {
+					minimalTags = append(minimalTags, convertToMinimalTag(tag))
+				}
+			}
+
+			r, err := response.OptimizeList(minimalTags)
 			if err != nil {
 				return nil, nil, fmt.Errorf("failed to marshal response: %w", err)
 			}
@@ -1670,7 +1683,16 @@ func ListReleases(t translations.TranslationHelperFunc) inventory.ServerTool {
 				return ghErrors.NewGitHubAPIStatusErrorResponse(ctx, "failed to list releases", resp, body), nil, nil
 			}
 
-			r, err := json.Marshal(releases)
+			minimalReleases := make([]MinimalRelease, 0, len(releases))
+			for _, release := range releases {
+				if release != nil {
+					minimalReleases = append(minimalReleases, convertToMinimalRelease(release))
+				}
+			}
+
+			r, err := response.OptimizeList(minimalReleases,
+				response.WithPreservedFields("html_url", "prerelease"),
+			)
 			if err != nil {
 				return nil, nil, fmt.Errorf("failed to marshal response: %w", err)
 			}

pkg/github/repositories_test.go

@@ -1053,23 +1053,30 @@ func Test_ListCommits(t *testing.T) {
 			textContent := getTextResult(t, result)
 
 			// Unmarshal and verify the result
-			var returnedCommits []MinimalCommit
+			var returnedCommits []map[string]any
 			err = json.Unmarshal([]byte(textContent.Text), &returnedCommits)
 			require.NoError(t, err)
 			assert.Len(t, returnedCommits, len(tc.expectedCommits))
 			for i, commit := range returnedCommits {
-				assert.Equal(t, tc.expectedCommits[i].GetSHA(), commit.SHA)
-				assert.Equal(t, tc.expectedCommits[i].GetHTMLURL(), commit.HTMLURL)
+				assert.Equal(t, tc.expectedCommits[i].GetSHA(), commit["sha"])
+				assert.Equal(t, tc.expectedCommits[i].GetHTMLURL(), commit["html_url"])
 				if tc.expectedCommits[i].Commit != nil {
-					assert.Equal(t, tc.expectedCommits[i].Commit.GetMessage(), commit.Commit.Message)
+					assert.Equal(t, tc.expectedCommits[i].Commit.GetMessage(), commit["commit.message"])
+					if tc.expectedCommits[i].Commit.Author != nil {
+						assert.Equal(t, tc.expectedCommits[i].Commit.Author.GetName(), commit["commit.author.name"])
+						assert.Equal(t, tc.expectedCommits[i].Commit.Author.GetEmail(), commit["commit.author.email"])
+						if tc.expectedCommits[i].Commit.Author.Date != nil {
+							assert.NotEmpty(t, commit["commit.author.date"], "commit.author.date should be present")
+						}
+					}
 				}
 				if tc.expectedCommits[i].Author != nil {
-					assert.Equal(t, tc.expectedCommits[i].Author.GetLogin(), commit.Author.Login)
+					assert.Equal(t, tc.expectedCommits[i].Author.GetLogin(), commit["author.login"])
 				}
 
 				// Files and stats are never included in list_commits
-				assert.Nil(t, commit.Files)
-				assert.Nil(t, commit.Stats)
+				assert.Nil(t, commit["files"])
+				assert.Nil(t, commit["stats"])
 			}
 		})
 	}
@@ -2791,15 +2798,15 @@ func Test_ListTags(t *testing.T) {
 			textContent := getTextResult(t, result)
 
 			// Parse and verify the result
-			var returnedTags []*github.RepositoryTag
+			var returnedTags []map[string]any
 			err = json.Unmarshal([]byte(textContent.Text), &returnedTags)
 			require.NoError(t, err)
 
 			// Verify each tag
 			require.Equal(t, len(tc.expectedTags), len(returnedTags))
 			for i, expectedTag := range tc.expectedTags {
-				assert.Equal(t, *expectedTag.Name, *returnedTags[i].Name)
-				assert.Equal(t, *expectedTag.Commit.SHA, *returnedTags[i].Commit.SHA)
+				assert.Equal(t, *expectedTag.Name, returnedTags[i]["name"])
+				assert.Equal(t, *expectedTag.Commit.SHA, returnedTags[i]["sha"])
 			}
 		})
 	}