Eliminate duplicate sys tool metadata in registerSysTools() (#1349)

The `registerSysTools()` function in `internal/server/unified.go` was
duplicating tool metadata (Name, Description, InputSchema) for each sys
tool—once when storing in the internal `ToolInfo` map and again when
registering with the SDK.

## Changes

- **Added `registerSysTool()` helper function** that encapsulates both
internal storage and SDK registration, accepting metadata parameters
once
- **Refactored `sys___init` and `sys___list_servers`** to use the
helper, eliminating ~22 lines of duplicated metadata definitions

## Example

Before:
```go
// Store tool info
us.tools["sys___init"] = &ToolInfo{
    Name: "sys___init",
    Description: "Initialize the MCPG system...",
    InputSchema: map[string]interface{}{...},
    // ...
}

// Register with SDK (duplicate metadata)
sdk.AddTool(us.server, &sdk.Tool{
    Name: "sys___init",
    Description: "Initialize the MCPG system...",
    InputSchema: map[string]interface{}{...},
}, handler)
```

After:
```go
us.registerSysTool(
    "sys___init",
    "Initialize the MCPG system...",
    map[string]interface{}{...},
    handler,
)
```

This establishes a single source of truth for sys tool metadata and
reduces the risk of schema drift between internal storage and SDK
registration.

> [!WARNING]
>
> <details>
> <summary>Firewall rules blocked me from connecting to one or more
addresses (expand for details)</summary>
>
> #### I tried to connect to the following addresses, but was blocked by
firewall rules:
>
> - `example.com`
> - Triggering command: `/tmp/go-build1598906572/b275/launcher.test
/tmp/go-build1598906572/b275/launcher.test
-test.testlogfile=/tmp/go-build1598906572/b275/testlog.txt
-test.paniconexit0 -test.timeout=10m0s -test.v=true go fmtsort/sort.go
64/pkg/tool/linu-o --output-dir /tmp/playwright--unsafeptr=false
--allowed-origin-unreachable=false
64/pkg/tool/linu/tmp/go-build1598906572/b064/vet.cfg` (dns block)
> - `invalid-host-that-does-not-exist-12345.com`
> - Triggering command: `/tmp/go-build1598906572/b260/config.test
/tmp/go-build1598906572/b260/config.test
-test.testlogfile=/tmp/go-build1598906572/b260/testlog.txt
-test.paniconexit0 -test.timeout=10m0s -test.v=true go
base64/base64.go--64 64/pkg/tool/linu-o` (dns block)
> - `nonexistent.local`
> - Triggering command: `/tmp/go-build1598906572/b275/launcher.test
/tmp/go-build1598906572/b275/launcher.test
-test.testlogfile=/tmp/go-build1598906572/b275/testlog.txt
-test.paniconexit0 -test.timeout=10m0s -test.v=true go fmtsort/sort.go
64/pkg/tool/linu-o --output-dir /tmp/playwright--unsafeptr=false
--allowed-origin-unreachable=false
64/pkg/tool/linu/tmp/go-build1598906572/b064/vet.cfg` (dns block)
> - `slow.example.com`
> - Triggering command: `/tmp/go-build1598906572/b275/launcher.test
/tmp/go-build1598906572/b275/launcher.test
-test.testlogfile=/tmp/go-build1598906572/b275/testlog.txt
-test.paniconexit0 -test.timeout=10m0s -test.v=true go fmtsort/sort.go
64/pkg/tool/linu-o --output-dir /tmp/playwright--unsafeptr=false
--allowed-origin-unreachable=false
64/pkg/tool/linu/tmp/go-build1598906572/b064/vet.cfg` (dns block)
> - `this-host-does-not-exist-12345.com`
> - Triggering command: `/tmp/go-build1598906572/b284/mcp.test
/tmp/go-build1598906572/b284/mcp.test
-test.testlogfile=/tmp/go-build1598906572/b284/testlog.txt
-test.paniconexit0 -test.timeout=10m0s -test.v=true go1.25.6 -c=4
-nolocalimports -importcfg /tmp/go-build1598906572/b191/importcfg -pack
/opt/hostedtoolcache/go/1.25.6/x64/src/net/http/internal/httpcommon/httpcommon.go`
(dns block)
>
> If you need me to access, download, or install something from one of
these locations, you can either:
>
> - Configure [Actions setup
steps](https://gh.io/copilot/actions-setup-steps) to set up my
environment, which run before the firewall is enabled
> - Add the appropriate URLs or hosts to the custom allowlist in this
repository's [Copilot coding agent
settings](https://github.com/github/gh-aw-mcpg/settings/copilot/coding_agent)
(admins only)
>
> </details>

<!-- START COPILOT ORIGINAL PROMPT -->



<details>

<summary>Original prompt</summary>

> 
> ----
> 
> *This section details on the original issue you should resolve*
> 
> <issue_title>[duplicate-code] Duplicate Code Analysis
Report</issue_title>
> <issue_description>*Analysis of commit
be3b856*
> 
> ## Summary
> 
> This analysis found **1 significant duplication pattern** in the Go
source files. The duplication occurs in `internal/server/unified.go`
where sys tool metadata (Name, Description, InputSchema) is defined
twice per tool — once for internal `ToolInfo` storage and again for the
SDK `sdk.Tool` registration.
> 
> ## Detected Patterns
> 
> 1. **Sys Tool Struct Data Duplication** - Severity: Medium - See
sub-issue #1348
> 
> ## Overall Impact
> 
> - **Total Duplicated Lines**: ~22 lines across 2 sys tools
> - **Affected Files**: 1 (`internal/server/unified.go`)
> - **Maintainability Risk**: Medium — schema/description changes to sys
tools require updating two locations, risking drift
> - **Refactoring Priority**: Low-Medium — localized to
`registerSysTools()`, no runtime risk, but creates update burden
> 
> ## Next Steps
> 
> 1. Review individual pattern sub-issue for detailed analysis
> 2. Implement a `registerSysTool` helper that accepts
name/description/schema once and handles both internal storage and SDK
registration
> 3. Verify no behavioral change after refactoring with existing tests
> 
> ## Analysis Metadata
> 
> - **Analyzed Files**: 64 Go source files (excluding test files)
> - **Detection Method**: Semantic and structural code analysis
> - **Commit**: be3b856
> - **Analysis Date**: 2026-02-24</issue_description>
> 
> ## Comments on the Issue (you are @claude[agent] in this section)
> 
> <comments>
> </comments>
> 


</details>



<!-- START COPILOT CODING AGENT SUFFIX -->

- Fixes #1347

Author: lpcox

internal/server/unified.go

@@ -406,6 +406,29 @@ func (us *UnifiedServer) registerToolsFromBackend(serverID string) error {
 	return nil
 }
 
+// registerSysTool is a helper function that registers a sys tool by storing its metadata
+// in the internal tools map and registering it with the SDK. This eliminates duplication
+// of tool metadata (Name, Description, InputSchema) that was previously defined twice.
+func (us *UnifiedServer) registerSysTool(name, description string, inputSchema map[string]interface{}, handler func(context.Context, *sdk.CallToolRequest, interface{}) (*sdk.CallToolResult, interface{}, error)) {
+	// Store tool info
+	us.toolsMu.Lock()
+	us.tools[name] = &ToolInfo{
+		Name:        name,
+		Description: description,
+		InputSchema: inputSchema,
+		BackendID:   "sys",
+		Handler:     handler,
+	}
+	us.toolsMu.Unlock()
+
+	// Register with SDK
+	sdk.AddTool(us.server, &sdk.Tool{
+		Name:        name,
+		Description: description,
+		InputSchema: inputSchema,
+	}, handler)
+}
+
 // registerSysTools registers built-in sys tools
 func (us *UnifiedServer) registerSysTools() error {
 	// Create sys_init handler
@@ -464,12 +487,11 @@ func (us *UnifiedServer) registerSysTools() error {
 		return nil, result, nil
 	}
 
-	// Store sys_init tool info
-	us.toolsMu.Lock()
-	us.tools["sys___init"] = &ToolInfo{
-		Name:        "sys___init",
-		Description: "Initialize the MCPG system and get available MCP servers",
-		InputSchema: map[string]interface{}{
+	// Register sys_init tool using helper
+	us.registerSysTool(
+		"sys___init",
+		"Initialize the MCPG system and get available MCP servers",
+		map[string]interface{}{
 			"type": "object",
 			"properties": map[string]interface{}{
 				"token": map[string]interface{}{
@@ -478,25 +500,8 @@ func (us *UnifiedServer) registerSysTools() error {
 				},
 			},
 		},
-		BackendID: "sys",
-		Handler:   sysInitHandler,
-	}
-	us.toolsMu.Unlock()
-
-	// Register with SDK
-	sdk.AddTool(us.server, &sdk.Tool{
-		Name:        "sys___init",
-		Description: "Initialize the MCPG system and get available MCP servers",
-		InputSchema: map[string]interface{}{
-			"type": "object",
-			"properties": map[string]interface{}{
-				"token": map[string]interface{}{
-					"type":        "string",
-					"description": "Authentication token for session initialization (can be empty for first call)",
-				},
-			},
-		},
-	}, sysInitHandler)
+		sysInitHandler,
+	)
 
 	// Create sys_list_servers handler
 	sysListHandler := func(ctx context.Context, req *sdk.CallToolRequest, args interface{}) (*sdk.CallToolResult, interface{}, error) {
@@ -524,29 +529,16 @@ func (us *UnifiedServer) registerSysTools() error {
 		return nil, result, nil
 	}
 
-	// Store sys_list_servers tool info
-	us.toolsMu.Lock()
-	us.tools["sys___list_servers"] = &ToolInfo{
-		Name:        "sys___list_servers",
-		Description: "List all configured MCP backend servers",
-		InputSchema: map[string]interface{}{
-			"type":       "object",
-			"properties": map[string]interface{}{},
-		},
-		BackendID: "sys",
-		Handler:   sysListHandler,
-	}
-	us.toolsMu.Unlock()
-
-	// Register with SDK
-	sdk.AddTool(us.server, &sdk.Tool{
-		Name:        "sys___list_servers",
-		Description: "List all configured MCP backend servers",
-		InputSchema: map[string]interface{}{
+	// Register sys_list_servers tool using helper
+	us.registerSysTool(
+		"sys___list_servers",
+		"List all configured MCP backend servers",
+		map[string]interface{}{
 			"type":       "object",
 			"properties": map[string]interface{}{},
 		},
-	}, sysListHandler)
+		sysListHandler,
+	)
 
 	log.Println("Registered 2 sys tools")
 	return nil