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Merged
mattt merged 2 commits into from
Aug 14, 2025
Merged

Add tool annotations #59

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8fe3b7e
Add tool annotations
mattt Aug 14, 2025
425521a
Add --no-annotations flag
mattt Aug 14, 2025
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13 changes: 10 additions & 3 deletions cmd/emcee/main.go
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Original file line number Diff line number Diff line change
Expand Up @@ -192,7 +192,11 @@ Authentication values can be provided directly or as 1Password secret references
// Create SDK server and register tools from OpenAPI
impl := &mcp.Implementation{Name: cmd.Name(), Version: version}
server := mcp.NewServer(impl, nil)
if err := internal.RegisterTools(server, specData, client); err != nil {
var opts []internal.RegisterToolsOption
if noAnnotations {
opts = append(opts, internal.WithoutAnnotations())
}
if err := internal.RegisterTools(server, specData, client, opts...); err != nil {
return fmt.Errorf("error registering tools: %w", err)
}

Expand All @@ -213,8 +217,9 @@ var (
timeout time.Duration
rps int

verbose bool
silent bool
verbose bool
silent bool
noAnnotations bool

version = "dev"
commit = "none"
Expand All @@ -235,6 +240,8 @@ func init() {
rootCmd.Flags().BoolVarP(&silent, "silent", "s", false, "Disable all logging")
rootCmd.MarkFlagsMutuallyExclusive("verbose", "silent")

rootCmd.Flags().BoolVar(&noAnnotations, "no-annotations", false, "Disable generated tool annotations")

rootCmd.Version = fmt.Sprintf("%s (commit: %s, built at: %s)", version, commit, date)
}

Expand Down
61 changes: 60 additions & 1 deletion internal/openapi.go
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Original file line number Diff line number Diff line change
Expand Up @@ -21,9 +21,22 @@ import (
"gopkg.in/yaml.v3"
)

// RegisterToolsOption configures RegisterTools behavior.
type RegisterToolsOption func(*registerToolsConfig)

type registerToolsConfig struct {
enableAnnotations bool
}

// WithoutAnnotations disables attaching REST-aware MCP ToolAnnotations for generated tools.
func WithoutAnnotations() RegisterToolsOption {
return func(cfg *registerToolsConfig) { cfg.enableAnnotations = false }
}

// RegisterTools parses the given OpenAPI specification and registers tools on the provided MCP server.
// All HTTP calls are executed using the provided http.Client. If the client is nil, http.DefaultClient is used.
func RegisterTools(server *mcp.Server, specData []byte, client *http.Client) error {
// By default, REST-aware MCP ToolAnnotations are attached to each tool. Pass options to change behavior.
func RegisterTools(server *mcp.Server, specData []byte, client *http.Client, opts ...RegisterToolsOption) error {
if len(specData) == 0 {
return fmt.Errorf("no OpenAPI spec data provided")
}
Expand All @@ -34,6 +47,14 @@ func RegisterTools(server *mcp.Server, specData []byte, client *http.Client) err
client = http.DefaultClient
}

// Defaults
cfg := &registerToolsConfig{enableAnnotations: true}
for _, opt := range opts {
if opt != nil {
opt(cfg)
}
}

doc, err := libopenapi.NewDocument(specData)
if err != nil {
return fmt.Errorf("error parsing OpenAPI spec: %w", err)
Expand Down Expand Up @@ -86,12 +107,14 @@ func RegisterTools(server *mcp.Server, specData []byte, client *http.Client) err
addParamToSchema(schema, param)
}
}

// Operation parameters
if op.op.Parameters != nil {
for _, param := range op.op.Parameters {
addParamToSchema(schema, param)
}
}

// Request body (application/json)
if op.op.RequestBody != nil && op.op.RequestBody.Content != nil {
if mediaType, ok := op.op.RequestBody.Content.Get("application/json"); ok && mediaType != nil {
Expand Down Expand Up @@ -121,6 +144,42 @@ func RegisterTools(server *mcp.Server, specData []byte, client *http.Client) err
InputSchema: schema,
}

if cfg.enableAnnotations {
// Derive MCP ToolAnnotations from REST conventions
title := op.op.Summary
if title == "" {
title = fmt.Sprintf("%s %s", op.method, p)
}
openWorld := true
destructiveTrue := true

Copilot AI Aug 14, 2025

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[nitpick] The variable destructiveTrue is defined but only used for POST, PUT, PATCH, and DELETE cases. Consider defining it only where needed or use a literal true directly in the assignments to reduce unnecessary variable declarations.

Suggested change
destructiveTrue := true

Copilot uses AI. Check for mistakes.
ann := &mcp.ToolAnnotations{
Title: title,
OpenWorldHint: &openWorld,
Comment thread
mattt marked this conversation as resolved.
}
switch op.method {
case "GET":
ann.ReadOnlyHint = true
ann.IdempotentHint = true
case "POST":
ann.ReadOnlyHint = false
ann.IdempotentHint = false
ann.DestructiveHint = &destructiveTrue
case "PUT":
ann.ReadOnlyHint = false
ann.IdempotentHint = true
ann.DestructiveHint = &destructiveTrue
case "PATCH":
ann.ReadOnlyHint = false
ann.IdempotentHint = false
ann.DestructiveHint = &destructiveTrue
case "DELETE":
ann.ReadOnlyHint = false
ann.IdempotentHint = true
ann.DestructiveHint = &destructiveTrue
}
tool.Annotations = ann
}

// Capture for handler
method := op.method
operation := op.op
Expand Down