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

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Merged
lpcox merged 1 commit into from
Feb 3, 2026
+16 −0
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[log] Add debug logging to MCP types schema normalization #606

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16 changes: 16 additions & 0 deletions internal/mcp/types.go
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Original file line number Diff line number Diff line change
Expand Up @@ -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"`
Expand Down Expand Up @@ -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)
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Copilot AI Feb 3, 2026

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The PR description states "7 strategic logging calls" but there are actually 9 log.Printf calls in the NormalizeInputSchema function (lines 64, 69, 80, 86, 95, 99, 109, 117-118, 132, and 136). Consider updating the PR description to reflect the accurate count.

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// 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",
Expand All @@ -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)

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Copilot AI Feb 3, 2026

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Remove trailing whitespace from this blank line. This improves consistency with Go formatting standards.

This issue also appears in the following locations of the same file:

  • line 119
  • line 65

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// 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
Expand All @@ -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",
Expand All @@ -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 {
Expand All @@ -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
}
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