Skip to content

mcp: change tool handler design #325

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 3 commits into from
Aug 20, 2025
Merged

mcp: change tool handler design #325

Show file tree
Hide file tree
Changes from 1 commit
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
037db67
mcp: change tool handler design
jba Aug 19, 2025
57aab1c
fix readme
jba Aug 20, 2025
96f5796
fix staticcheck
jba Aug 20, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
8 changes: 4 additions & 4 deletions examples/server/custom-transport/main.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -85,12 +85,12 @@ type HiArgs struct {
}

// SayHi is a tool handler that responds with a greeting.
func SayHi(ctx context.Context, req *mcp.ServerRequest[*mcp.CallToolParamsFor[HiArgs]]) (*mcp.CallToolResultFor[struct{}], error) {
return &mcp.CallToolResultFor[struct{}]{
func SayHi(ctx context.Context, req *mcp.ServerRequest[*mcp.CallToolParams], args HiArgs) (*mcp.CallToolResult, struct{}, error) {
return &mcp.CallToolResult{
Content: []mcp.Content{
&mcp.TextContent{Text: "Hi " + req.Params.Arguments.Name},
&mcp.TextContent{Text: "Hi " + args.Name},
},
}, nil
}, struct{}{}, nil
}

func main() {
Expand Down
8 changes: 4 additions & 4 deletions examples/server/hello/main.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -22,12 +22,12 @@ type HiArgs struct {
Name string `json:"name" jsonschema:"the name to say hi to"`
}

func SayHi(ctx context.Context, req *mcp.ServerRequest[*mcp.CallToolParamsFor[HiArgs]]) (*mcp.CallToolResultFor[struct{}], error) {
return &mcp.CallToolResultFor[struct{}]{
func SayHi(ctx context.Context, req *mcp.ServerRequest[*mcp.CallToolParams], args HiArgs) (*mcp.CallToolResult, any, error) {
return &mcp.CallToolResult{
Content: []mcp.Content{
&mcp.TextContent{Text: "Hi " + req.Params.Arguments.Name},
&mcp.TextContent{Text: "Hi " + args.Name},
},
}, nil
}, nil, nil
}

func PromptHi(ctx context.Context, ss *mcp.ServerSession, params *mcp.GetPromptParams) (*mcp.GetPromptResult, error) {
Expand Down
99 changes: 45 additions & 54 deletions examples/server/memory/kb.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -431,12 +431,12 @@ func (k knowledgeBase) openNodes(names []string) (KnowledgeGraph, error) {
}, nil
}

func (k knowledgeBase) CreateEntities(ctx context.Context, req *mcp.ServerRequest[*mcp.CallToolParamsFor[CreateEntitiesArgs]]) (*mcp.CallToolResultFor[CreateEntitiesResult], error) {
var res mcp.CallToolResultFor[CreateEntitiesResult]
func (k knowledgeBase) CreateEntities(ctx context.Context, req *mcp.ServerRequest[*mcp.CallToolParams], args CreateEntitiesArgs) (*mcp.CallToolResult, CreateEntitiesResult, error) {
var res mcp.CallToolResult

entities, err := k.createEntities(req.Params.Arguments.Entities)
entities, err := k.createEntities(args.Entities)
if err != nil {
return nil, err
return nil, CreateEntitiesResult{}, err
}

res.Content = []mcp.Content{
Expand All @@ -447,136 +447,127 @@ func (k knowledgeBase) CreateEntities(ctx context.Context, req *mcp.ServerReques
Entities: entities,
}

return &res, nil
return &res, CreateEntitiesResult{Entities: entities}, nil
}

func (k knowledgeBase) CreateRelations(ctx context.Context, req *mcp.ServerRequest[*mcp.CallToolParamsFor[CreateRelationsArgs]]) (*mcp.CallToolResultFor[CreateRelationsResult], error) {
var res mcp.CallToolResultFor[CreateRelationsResult]
func (k knowledgeBase) CreateRelations(ctx context.Context, req *mcp.ServerRequest[*mcp.CallToolParams], args CreateRelationsArgs) (*mcp.CallToolResult, CreateRelationsResult, error) {
var res mcp.CallToolResult

relations, err := k.createRelations(req.Params.Arguments.Relations)
relations, err := k.createRelations(args.Relations)
if err != nil {
return nil, err
return nil, CreateRelationsResult{}, err
}

res.Content = []mcp.Content{
&mcp.TextContent{Text: "Relations created successfully"},
}

res.StructuredContent = CreateRelationsResult{
Relations: relations,
}

return &res, nil
return &res, CreateRelationsResult{Relations: relations}, nil
}

func (k knowledgeBase) AddObservations(ctx context.Context, req *mcp.ServerRequest[*mcp.CallToolParamsFor[AddObservationsArgs]]) (*mcp.CallToolResultFor[AddObservationsResult], error) {
var res mcp.CallToolResultFor[AddObservationsResult]
func (k knowledgeBase) AddObservations(ctx context.Context, req *mcp.ServerRequest[*mcp.CallToolParams], args AddObservationsArgs) (*mcp.CallToolResult, AddObservationsResult, error) {
var res mcp.CallToolResult

observations, err := k.addObservations(req.Params.Arguments.Observations)
observations, err := k.addObservations(args.Observations)
if err != nil {
return nil, err
return nil, AddObservationsResult{}, err
}

res.Content = []mcp.Content{
&mcp.TextContent{Text: "Observations added successfully"},
}

res.StructuredContent = AddObservationsResult{
return &res, AddObservationsResult{
Observations: observations,
}

return &res, nil
}, nil
}

func (k knowledgeBase) DeleteEntities(ctx context.Context, req *mcp.ServerRequest[*mcp.CallToolParamsFor[DeleteEntitiesArgs]]) (*mcp.CallToolResultFor[struct{}], error) {
var res mcp.CallToolResultFor[struct{}]
func (k knowledgeBase) DeleteEntities(ctx context.Context, req *mcp.ServerRequest[*mcp.CallToolParams], args DeleteEntitiesArgs) (*mcp.CallToolResult, struct{}, error) {
var res mcp.CallToolResult

err := k.deleteEntities(req.Params.Arguments.EntityNames)
err := k.deleteEntities(args.EntityNames)
if err != nil {
return nil, err
return nil, struct{}{}, err
}

res.Content = []mcp.Content{
&mcp.TextContent{Text: "Entities deleted successfully"},
}

return &res, nil
return &res, struct{}{}, nil
}

func (k knowledgeBase) DeleteObservations(ctx context.Context, req *mcp.ServerRequest[*mcp.CallToolParamsFor[DeleteObservationsArgs]]) (*mcp.CallToolResultFor[struct{}], error) {
var res mcp.CallToolResultFor[struct{}]
func (k knowledgeBase) DeleteObservations(ctx context.Context, req *mcp.ServerRequest[*mcp.CallToolParams], args DeleteObservationsArgs) (*mcp.CallToolResult, struct{}, error) {
var res mcp.CallToolResult
Copy link
Contributor

@findleyr findleyr Aug 20, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Nit: preexisting: just inline into the literal below.

Copy link
Contributor Author

@jba jba Aug 21, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I don't understand.


err := k.deleteObservations(req.Params.Arguments.Deletions)
err := k.deleteObservations(args.Deletions)
if err != nil {
return nil, err
return nil, struct{}{}, err
}

res.Content = []mcp.Content{
&mcp.TextContent{Text: "Observations deleted successfully"},
}

return &res, nil
return &res, struct{}{}, nil
}

func (k knowledgeBase) DeleteRelations(ctx context.Context, req *mcp.ServerRequest[*mcp.CallToolParamsFor[DeleteRelationsArgs]]) (*mcp.CallToolResultFor[struct{}], error) {
var res mcp.CallToolResultFor[struct{}]
func (k knowledgeBase) DeleteRelations(ctx context.Context, req *mcp.ServerRequest[*mcp.CallToolParams], args DeleteRelationsArgs) (*mcp.CallToolResult, struct{}, error) {
var res mcp.CallToolResult

err := k.deleteRelations(req.Params.Arguments.Relations)
err := k.deleteRelations(args.Relations)
if err != nil {
return nil, err
return nil, struct{}{}, err
}

res.Content = []mcp.Content{
&mcp.TextContent{Text: "Relations deleted successfully"},
}

return &res, nil
return &res, struct{}{}, nil
}

func (k knowledgeBase) ReadGraph(ctx context.Context, req *mcp.ServerRequest[*mcp.CallToolParamsFor[struct{}]]) (*mcp.CallToolResultFor[KnowledgeGraph], error) {
var res mcp.CallToolResultFor[KnowledgeGraph]
func (k knowledgeBase) ReadGraph(ctx context.Context, req *mcp.ServerRequest[*mcp.CallToolParams], args any) (*mcp.CallToolResult, KnowledgeGraph, error) {
var res mcp.CallToolResult

graph, err := k.loadGraph()
if err != nil {
return nil, err
return nil, KnowledgeGraph{}, err
}

res.Content = []mcp.Content{
&mcp.TextContent{Text: "Graph read successfully"},
}

res.StructuredContent = graph
return &res, nil
return &res, graph, nil
}

func (k knowledgeBase) SearchNodes(ctx context.Context, req *mcp.ServerRequest[*mcp.CallToolParamsFor[SearchNodesArgs]]) (*mcp.CallToolResultFor[KnowledgeGraph], error) {
var res mcp.CallToolResultFor[KnowledgeGraph]
func (k knowledgeBase) SearchNodes(ctx context.Context, req *mcp.ServerRequest[*mcp.CallToolParams], args SearchNodesArgs) (*mcp.CallToolResult, KnowledgeGraph, error) {
var res mcp.CallToolResult

graph, err := k.searchNodes(req.Params.Arguments.Query)
graph, err := k.searchNodes(args.Query)
if err != nil {
return nil, err
return nil, KnowledgeGraph{}, err
}

res.Content = []mcp.Content{
&mcp.TextContent{Text: "Nodes searched successfully"},
}

res.StructuredContent = graph
return &res, nil
return &res, KnowledgeGraph{}, nil
}

func (k knowledgeBase) OpenNodes(ctx context.Context, req *mcp.ServerRequest[*mcp.CallToolParamsFor[OpenNodesArgs]]) (*mcp.CallToolResultFor[KnowledgeGraph], error) {
var res mcp.CallToolResultFor[KnowledgeGraph]
func (k knowledgeBase) OpenNodes(ctx context.Context, req *mcp.ServerRequest[*mcp.CallToolParams], args OpenNodesArgs) (*mcp.CallToolResult, KnowledgeGraph, error) {
var res mcp.CallToolResult

graph, err := k.openNodes(req.Params.Arguments.Names)
graph, err := k.openNodes(args.Names)
if err != nil {
return nil, err
return nil, KnowledgeGraph{}, err
}

res.Content = []mcp.Content{
&mcp.TextContent{Text: "Nodes opened successfully"},
}

res.StructuredContent = graph
return &res, nil
return &res, graph, nil
}
Loading
Loading