[log] Add debug logging to MCP types schema normalization (#606)

## Summary

Enhanced `internal/mcp/types.go` with debug logging to improve
troubleshooting of MCP tool schema normalization.

## Changes Made

Added debug logger declaration and 7 strategic logging calls to the
`NormalizeInputSchema` function:

1. **Function entry logging** - Logs when schema normalization starts
for a tool
2. **Nil schema detection** - Logs when a backend provides no input
schema
3. **Type field analysis** - Logs schema structure (presence of type
field)
4. **Missing type handling** - Logs when schema lacks type field and
properties status
5. **Type normalization** - Logs when object type is added to schema
6. **Non-object type handling** - Logs when schema has non-object or
invalid type
7. **Properties validation** - Logs object schema structure (properties
and additionalProperties)
8. **Properties normalization** - Logs when empty properties are added
9. **Valid schema confirmation** - Logs when no normalization is needed

## Benefits

- Easier debugging of schema validation issues from backend MCP servers
- Visibility into which normalizations are applied and why
- Better understanding of tool registration flow
- No side effects in log arguments (all values already computed)

## Testing

- Added logger following project convention: `var log =
logger.New("mcp:types")`
- All logging statements use parameters already available in scope
- No expensive computations in log arguments
- Preserved existing file logger warnings for operational visibility

## Quality Checklist

- ✅ Exactly 1 file modified (focused, single-file PR)
- ✅ No test files modified
- ✅ Logger naming follows `pkg:filename` convention (`mcp:types`)
- ✅ Logger arguments don't compute anything or cause side effects
- ✅ Logging messages are meaningful and helpful for debugging
- ✅ No duplicate logging with existing logs
- ✅ Import statements properly ordered
- ✅ Preserved all existing file logger calls for operational logging

## Example Debug Output

With `DEBUG=mcp:*`, developers will see:

```````
mcp:types Normalizing input schema for tool: github-search
mcp:types Tool github-search schema analysis: hasType=true
mcp:types Tool github-search object type schema: hasProperties=true, hasAdditionalProperties=false
mcp:types Tool github-search schema is valid, no normalization needed
``````

Or when normalization is needed:

``````
mcp:types Normalizing input schema for tool: legacy-tool
mcp:types Tool legacy-tool has nil schema, applying default empty object schema
```````


> AI generated by [Go Logger
Enhancement](https://github.com/github/gh-aw-mcpg/actions/runs/21629700132)

<!-- gh-aw-workflow-id: go-logger -->

Author: lpcox

internal/mcp/types.go

@@ -6,6 +6,8 @@ import (
 	"github.com/github/gh-aw-mcpg/internal/logger"
 )
 
+var log = logger.New("mcp:types")
+
 // Request represents a JSON-RPC 2.0 request
 type Request struct {
 	JSONRPC string          `json:"jsonrpc"`
@@ -59,9 +61,12 @@ type ContentItem struct {
 //     but is missing the required "properties" field, we add an empty properties
 //     object to make it valid per JSON Schema standards.
 func NormalizeInputSchema(schema map[string]interface{}, toolName string) map[string]interface{} {
+	log.Printf("Normalizing input schema for tool: %s", toolName)
+	
 	// If backend didn't provide a schema, use a default empty object schema
 	// This allows the tool to be registered and clients will see it accepts any parameters
 	if schema == nil {
+		log.Printf("Tool %s has nil schema, applying default empty object schema", toolName)
 		logger.LogWarn("backend", "Tool schema normalized: %s - backend provided no inputSchema, using default empty object schema", toolName)
 		return map[string]interface{}{
 			"type":       "object",
@@ -72,10 +77,13 @@ func NormalizeInputSchema(schema map[string]interface{}, toolName string) map[st
 	// Check if this is an object type schema
 	typeVal, hasType := schema["type"]
 
+	log.Printf("Tool %s schema analysis: hasType=%v", toolName, hasType)
+	
 	// If schema has no type but has properties, it's implicitly an object type
 	// The MCP SDK requires "type": "object" to be present, so add it
 	if !hasType {
 		_, hasProperties := schema["properties"]
+		log.Printf("Tool %s has no type field, hasProperties=%v", toolName, hasProperties)
 		if hasProperties {
 			logger.LogWarn("backend", "Tool schema normalized: %s - added 'type': 'object' to schema with properties", toolName)
 			// Create a copy of the schema to avoid modifying the original
@@ -84,9 +92,11 @@ func NormalizeInputSchema(schema map[string]interface{}, toolName string) map[st
 				normalized[k] = v
 			}
 			normalized["type"] = "object"
+			log.Printf("Tool %s schema normalized: added object type", toolName)
 			return normalized
 		}
 		// Schema without type and without properties - assume it's an empty object schema
+		log.Printf("Tool %s has no type and no properties, using empty object schema", toolName)
 		logger.LogWarn("backend", "Tool schema normalized: %s - schema missing type, assuming empty object schema", toolName)
 		return map[string]interface{}{
 			"type":       "object",
@@ -96,13 +106,17 @@ func NormalizeInputSchema(schema map[string]interface{}, toolName string) map[st
 
 	typeStr, isString := typeVal.(string)
 	if !isString || typeStr != "object" {
+		log.Printf("Tool %s has non-object type or invalid type value, returning schema as-is", toolName)
 		return schema
 	}
 
 	// Check if properties field exists
 	_, hasProperties := schema["properties"]
 	_, hasAdditionalProperties := schema["additionalProperties"]
 
+	log.Printf("Tool %s object type schema: hasProperties=%v, hasAdditionalProperties=%v", 
+		toolName, hasProperties, hasAdditionalProperties)
+	
 	// If it's an object type but missing both properties and additionalProperties,
 	// add an empty properties object to make it valid
 	if !hasProperties && !hasAdditionalProperties {
@@ -115,8 +129,10 @@ func NormalizeInputSchema(schema map[string]interface{}, toolName string) map[st
 		}
 		normalized["properties"] = map[string]interface{}{}
 
+		log.Printf("Tool %s schema normalized: added empty properties field", toolName)
 		return normalized
 	}
 
+	log.Printf("Tool %s schema is valid, no normalization needed", toolName)
 	return schema
 }