diff --git a/pkg/github/discussions.go b/pkg/github/discussions.go
index 68ed014b2..ab631ecb2 100644
--- a/pkg/github/discussions.go
+++ b/pkg/github/discussions.go
@@ -11,7 +11,6 @@ import (
 	"github.com/github/github-mcp-server/pkg/scopes"
 	"github.com/github/github-mcp-server/pkg/translations"
 	"github.com/github/github-mcp-server/pkg/utils"
-	"github.com/go-viper/mapstructure/v2"
 	"github.com/google/go-github/v87/github"
 	"github.com/google/jsonschema-go/jsonschema"
 	"github.com/modelcontextprotocol/go-sdk/mcp"
@@ -313,15 +312,19 @@ func GetDiscussion(t translations.TranslationHelperFunc) inventory.ServerTool {
 		},
 		[]scopes.Scope{scopes.Repo},
 		func(ctx context.Context, deps ToolDependencies, _ *mcp.CallToolRequest, args map[string]any) (*mcp.CallToolResult, any, error) {
-			// Decode params
-			var params struct {
-				Owner            string
-				Repo             string
-				DiscussionNumber int32
+			owner, err := RequiredParam[string](args, "owner")
+			if err != nil {
+				return utils.NewToolResultError(err.Error()), nil, nil
 			}
-			if err := mapstructure.WeakDecode(args, &params); err != nil {
+			repo, err := RequiredParam[string](args, "repo")
+			if err != nil {
 				return utils.NewToolResultError(err.Error()), nil, nil
 			}
+			discussionNumber, err := RequiredInt(args, "discussionNumber")
+			if err != nil {
+				return utils.NewToolResultError(err.Error()), nil, nil
+			}
+
 			client, err := deps.GetGQLClient(ctx)
 			if err != nil {
 				return utils.NewToolResultError(fmt.Sprintf("failed to get GitHub GQL client: %v", err)), nil, nil
@@ -345,9 +348,9 @@ func GetDiscussion(t translations.TranslationHelperFunc) inventory.ServerTool {
 				} `graphql:"repository(owner: $owner, name: $repo)"`
 			}
 			vars := map[string]any{
-				"owner":            githubv4.String(params.Owner),
-				"repo":             githubv4.String(params.Repo),
-				"discussionNumber": githubv4.Int(params.DiscussionNumber),
+				"owner":            githubv4.String(owner),
+				"repo":             githubv4.String(repo),
+				"discussionNumber": githubv4.Int(discussionNumber),
 			}
 			if err := client.Query(ctx, &q, vars); err != nil {
 				return utils.NewToolResultError(err.Error()), nil, nil
@@ -384,7 +387,7 @@ func GetDiscussion(t translations.TranslationHelperFunc) inventory.ServerTool {
 			result := utils.NewToolResultText(string(out))
 			// Discussion content is user-authored (untrusted); confidentiality
 			// follows repo visibility.
-			result = attachRepoVisibilityIFCLabelLazy(ctx, deps, params.Owner, params.Repo, result, ifc.LabelRepoUserContent)
+			result = attachRepoVisibilityIFCLabelLazy(ctx, deps, owner, repo, result, ifc.LabelRepoUserContent)
 			return result, nil, nil
 		},
 	)
@@ -425,13 +428,16 @@ func GetDiscussionComments(t translations.TranslationHelperFunc) inventory.Serve
 		},
 		[]scopes.Scope{scopes.Repo},
 		func(ctx context.Context, deps ToolDependencies, _ *mcp.CallToolRequest, args map[string]any) (*mcp.CallToolResult, any, error) {
-			// Decode params
-			var params struct {
-				Owner            string
-				Repo             string
-				DiscussionNumber int32
+			owner, err := RequiredParam[string](args, "owner")
+			if err != nil {
+				return utils.NewToolResultError(err.Error()), nil, nil
+			}
+			repo, err := RequiredParam[string](args, "repo")
+			if err != nil {
+				return utils.NewToolResultError(err.Error()), nil, nil
 			}
-			if err := mapstructure.WeakDecode(args, &params); err != nil {
+			discussionNumber, err := RequiredInt(args, "discussionNumber")
+			if err != nil {
 				return utils.NewToolResultError(err.Error()), nil, nil
 			}
 
@@ -467,9 +473,9 @@ func GetDiscussionComments(t translations.TranslationHelperFunc) inventory.Serve
 			}
 
 			vars := map[string]any{
-				"owner":            githubv4.String(params.Owner),
-				"repo":             githubv4.String(params.Repo),
-				"discussionNumber": githubv4.Int(params.DiscussionNumber),
+				"owner":            githubv4.String(owner),
+				"repo":             githubv4.String(repo),
+				"discussionNumber": githubv4.Int(discussionNumber),
 				"first":            githubv4.Int(*paginationParams.First),
 			}
 			if paginationParams.After != nil {
@@ -592,7 +598,7 @@ func GetDiscussionComments(t translations.TranslationHelperFunc) inventory.Serve
 			result := utils.NewToolResultText(string(out))
 			// Discussion comments are user-authored (untrusted); confidentiality
 			// follows repo visibility.
-			result = attachRepoVisibilityIFCLabelLazy(ctx, deps, params.Owner, params.Repo, result, ifc.LabelRepoUserContent)
+			result = attachRepoVisibilityIFCLabelLazy(ctx, deps, owner, repo, result, ifc.LabelRepoUserContent)
 			return result, nil, nil
 		},
 	)
diff --git a/pkg/github/discussions_test.go b/pkg/github/discussions_test.go
index 36fdb6c43..3a090500f 100644
--- a/pkg/github/discussions_test.go
+++ b/pkg/github/discussions_test.go
@@ -590,8 +590,47 @@ func Test_GetDiscussion(t *testing.T) {
 	}
 }
 
+func Test_GetDiscussionRequiredParams(t *testing.T) {
+	t.Parallel()
+
+	toolDef := GetDiscussion(translations.NullTranslationHelper)
+	handler := toolDef.Handler(BaseDeps{GQLClient: githubv4.NewClient(githubv4mock.NewMockedHTTPClient())})
+
+	tests := []struct {
+		name           string
+		requestArgs    map[string]any
+		expectedErrMsg string
+	}{
+		{
+			name:           "missing owner",
+			requestArgs:    map[string]any{"repo": "repo", "discussionNumber": float64(1)},
+			expectedErrMsg: "missing required parameter: owner",
+		},
+		{
+			name:           "missing repo",
+			requestArgs:    map[string]any{"owner": "owner", "discussionNumber": float64(1)},
+			expectedErrMsg: "missing required parameter: repo",
+		},
+		{
+			name:           "missing discussionNumber",
+			requestArgs:    map[string]any{"owner": "owner", "repo": "repo"},
+			expectedErrMsg: "missing required parameter: discussionNumber",
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			req := createMCPRequest(tc.requestArgs)
+			res, err := handler(ContextWithDeps(context.Background(), BaseDeps{}), &req)
+			require.NoError(t, err)
+			require.True(t, res.IsError)
+			assert.Contains(t, getTextResult(t, res).Text, tc.expectedErrMsg)
+		})
+	}
+}
+
 func Test_GetDiscussionWithStringNumber(t *testing.T) {
-	// Test that WeakDecode handles string discussionNumber from MCP clients
+	// Test that RequiredInt handles string discussionNumber from MCP clients
 	toolDef := GetDiscussion(translations.NullTranslationHelper)
 
 	qGetDiscussion := "query($discussionNumber:Int!$owner:String!$repo:String!){repository(owner: $owner, name: $repo){discussion(number: $discussionNumber){number,title,body,createdAt,closed,isAnswered,answerChosenAt,url,category{name}}}}"
@@ -723,8 +762,47 @@ func Test_GetDiscussionComments(t *testing.T) {
 	assert.Equal(t, "This is the second comment", response.Comments[1].Body)
 }
 
+func Test_GetDiscussionCommentsRequiredParams(t *testing.T) {
+	t.Parallel()
+
+	toolDef := GetDiscussionComments(translations.NullTranslationHelper)
+	handler := toolDef.Handler(BaseDeps{GQLClient: githubv4.NewClient(githubv4mock.NewMockedHTTPClient())})
+
+	tests := []struct {
+		name           string
+		requestArgs    map[string]any
+		expectedErrMsg string
+	}{
+		{
+			name:           "missing owner",
+			requestArgs:    map[string]any{"repo": "repo", "discussionNumber": float64(1)},
+			expectedErrMsg: "missing required parameter: owner",
+		},
+		{
+			name:           "missing repo",
+			requestArgs:    map[string]any{"owner": "owner", "discussionNumber": float64(1)},
+			expectedErrMsg: "missing required parameter: repo",
+		},
+		{
+			name:           "missing discussionNumber",
+			requestArgs:    map[string]any{"owner": "owner", "repo": "repo"},
+			expectedErrMsg: "missing required parameter: discussionNumber",
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			req := createMCPRequest(tc.requestArgs)
+			res, err := handler(ContextWithDeps(context.Background(), BaseDeps{}), &req)
+			require.NoError(t, err)
+			require.True(t, res.IsError)
+			assert.Contains(t, getTextResult(t, res).Text, tc.expectedErrMsg)
+		})
+	}
+}
+
 func Test_GetDiscussionCommentsWithStringNumber(t *testing.T) {
-	// Test that WeakDecode handles string discussionNumber from MCP clients
+	// Test that RequiredInt handles string discussionNumber from MCP clients
 	toolDef := GetDiscussionComments(translations.NullTranslationHelper)
 
 	qGetComments := "query($after:String$discussionNumber:Int!$first:Int!$owner:String!$repo:String!){repository(owner: $owner, name: $repo){discussion(number: $discussionNumber){comments(first: $first, after: $after){nodes{id,body,isAnswer},pageInfo{hasNextPage,hasPreviousPage,startCursor,endCursor},totalCount}}}}"