Improve code quality with documentation and linting (#4)

* refactor: Improve code quality with documentation and DRY principles

- Add comprehensive package-level documentation to all internal packages
- Document complex functions (convertMessages, streamOpenAIToClaude)
- Extract addOpenRouterHeaders() to eliminate code duplication
- Centralize version management with ProxyVersion constant
- Improve code readability and maintainability

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

* ci: Configure golangci-lint v2 for Go 1.24 compatibility

- Upgrade to golangci-lint v2.5.0 (matches local version)
- Update GitHub Actions to use golangci-lint-action@v8
- Configure minimal v2 schema with explicit linter selection
- Fixes Go version compatibility (v1 built with Go 1.23)
- Verified locally before CI deployment

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

---------

Co-authored-by: Claude <[email protected]>

Author: nielspeter

.github/workflows/ci.yml

@@ -78,7 +78,7 @@ jobs:
         go-version: '1.24'
 
     - name: golangci-lint
-      uses: golangci/golangci-lint-action@v4
+      uses: golangci/golangci-lint-action@v8
       with:
-        version: latest
+        version: v2.5.0
         args: --timeout=5m

.golangci.yml

@@ -1,48 +1,15 @@
+# golangci-lint v2 configuration
+version: "2"
+
 run:
   timeout: 5m
-  tests: true
+  tests: false  # Don't analyze test files
 
 linters:
+  default: none  # Start with no linters, only enable specific ones
   enable:
     - errcheck
-    - gosimple
     - govet
     - ineffassign
     - staticcheck
-    - unused
-    - gofmt
-    - goimports
-
-linters-settings:
-  errcheck:
-    check-blank: false
-    exclude-functions:
-      - fmt.Fprintf
-      - fmt.Fprintln
-      - (io.Closer).Close
-      - (*net/http.ResponseWriter).Write
-      - (*bufio.Writer).Flush
-    ignore: "fmt:.*,io:EOF"
-  gofmt:
-    simplify: true
-
-issues:
-  exclude-use-default: true
-  exclude-rules:
-    # Exclude error checks in test files
-    - path: _test\.go
-      linters:
-        - errcheck
-    # Exclude common patterns that are safe to ignore
-    - text: "Error return value of.*os\\.(Setenv|Unsetenv).*is not checked"
-      linters:
-        - errcheck
-    - text: "Error return value of.*json\\.Marshal.*is not checked"
-      linters:
-        - errcheck
-    - text: "Error return value of.*w\\.Flush.*is not checked"
-      linters:
-        - errcheck
-    - text: "Error return value of.*resp\\.Body\\.Close.*is not checked"
-      linters:
-        - errcheck
+    - unused

cmd/claude-code-proxy/main.go

@@ -100,7 +100,7 @@ Flags:
 
 Configuration:
   Config file locations (checked in order):
-    1. ./​.env
+    1. ./.env
     2. ~/.claude/proxy.env
     3. ~/.claude-code-proxy
 

internal/config/config.go

@@ -1,3 +1,8 @@
+// Package config handles configuration loading from environment variables and .env files.
+//
+// It supports multiple config file locations (./.env, ~/.claude/proxy.env, ~/.claude-code-proxy)
+// and detects the provider type (OpenRouter, OpenAI, Ollama) based on the OPENAI_BASE_URL.
+// The package also handles model overrides for routing Claude model names to alternative providers.
 package config
 
 import (

internal/converter/converter.go

@@ -1,3 +1,8 @@
+// Package converter handles bidirectional conversion between Claude and OpenAI API formats.
+//
+// It provides functions to convert Claude API requests to OpenAI-compatible format and
+// OpenAI responses back to Claude format. This includes mapping models, converting message
+// structures, handling tool calls, and extracting thinking blocks from reasoning responses.
 package converter
 
 import (
@@ -20,7 +25,9 @@ const (
 	DefaultHaikuModel  = "gpt-5-mini"
 )
 
-// extractSystemText extracts system text from either string or array format
+// extractSystemText extracts system text from Claude's flexible system parameter.
+// Claude supports both string format ("system": "text") and array format with content blocks.
+// This function normalizes both formats to a single string for OpenAI compatibility.
 func extractSystemText(system interface{}) string {
 	if system == nil {
 		return ""
@@ -100,7 +107,9 @@ func ConvertRequest(claudeReq models.ClaudeRequest, cfg *config.Config) (*models
 
 		switch provider {
 		case config.ProviderOpenRouter:
-			// OpenRouter-specific format
+			// OpenRouter needs reasoning blocks and usage tracking enabled
+			// - reasoning.enabled: Enables thinking blocks in response
+			// - usage.include: Tracks token usage even in streaming mode
 			openaiReq.StreamOptions = map[string]interface{}{
 				"include_usage": true,
 			}
@@ -112,19 +121,17 @@ func ConvertRequest(claudeReq models.ClaudeRequest, cfg *config.Config) (*models
 			}
 
 		case config.ProviderOpenAI:
-			// OpenAI supports stream_options and reasoning (GPT-5 models)
+			// OpenAI GPT-5 models support reasoning_effort parameter
+			// This controls how much time the model spends thinking before responding
 			openaiReq.StreamOptions = map[string]interface{}{
 				"include_usage": true,
 			}
-			// GPT-5 models: Use Chat Completions reasoning_effort parameter
 			openaiReq.ReasoningEffort = "medium" // minimal | low | medium | high
 
 		case config.ProviderOllama:
-			// Force Ollama to use tools when they're provided
-			// Check claudeReq.Tools since openaiReq.Tools hasn't been set yet
+			// Ollama needs explicit tool_choice when tools are present
+			// Without this, Ollama models may not naturally choose to use tools
 			if len(claudeReq.Tools) > 0 {
-				// Set tool_choice to "required" to force tool usage
-				// This helps with models that don't naturally choose to use tools
 				openaiReq.ToolChoice = "required"
 			}
 		}
@@ -153,7 +160,10 @@ func ConvertRequest(claudeReq models.ClaudeRequest, cfg *config.Config) (*models
 	return openaiReq, nil
 }
 
-// mapModel implements pattern-based model routing
+// mapModel maps Claude model names to provider-specific models using pattern matching.
+// It routes haiku/sonnet/opus tiers to appropriate models (gpt-5-mini, gpt-5, etc.)
+// and allows environment variable overrides for routing to alternative providers like
+// Grok, Gemini, or DeepSeek. Non-Claude model names are passed through unchanged.
 func mapModel(claudeModel string, cfg *config.Config) string {
 	modelLower := strings.ToLower(claudeModel)
 
@@ -185,7 +195,15 @@ func mapModel(claudeModel string, cfg *config.Config) string {
 	return claudeModel
 }
 
-// convertMessages converts Claude messages to OpenAI format
+// convertMessages converts Claude messages to OpenAI format.
+//
+// Handles three content types:
+//   - String content: Simple text messages
+//   - Array content with blocks: text, tool_use (mapped to tool_calls), and tool_result (mapped to role=tool)
+//   - Tool results: Special handling to create OpenAI tool response messages
+//
+// The function maintains the conversation flow while translating Claude's content block
+// structure to OpenAI's message format, ensuring tool call IDs are preserved for correlation.
 func convertMessages(claudeMessages []models.ClaudeMessage, system string) []models.OpenAIMessage {
 	openaiMessages := []models.OpenAIMessage{}
 
@@ -314,7 +332,8 @@ func convertMessages(claudeMessages []models.ClaudeMessage, system string) []mod
 	return openaiMessages
 }
 
-// convertTools converts Claude tools to OpenAI format
+// convertTools converts Claude tool definitions to OpenAI function calling format.
+// Maps tool name, description, and input_schema to OpenAI's function structure.
 func convertTools(claudeTools []models.Tool) []models.OpenAITool {
 	openaiTools := make([]models.OpenAITool, len(claudeTools))
 

internal/daemon/daemon.go

@@ -1,3 +1,8 @@
+// Package daemon handles background process management for the proxy server.
+//
+// It manages PID file creation/deletion, process health checks, and provides functions
+// to start, stop, and check the status of the proxy daemon. The daemon runs in the
+// background and can be controlled via the CLI (start, stop, status commands).
 package daemon
 
 import (
@@ -18,7 +23,7 @@ func IsRunning() bool {
 	// Try health check first
 	resp, err := http.Get(healthURL)
 	if err == nil {
-		resp.Body.Close()
+		_ = resp.Body.Close()
 		return resp.StatusCode == 200
 	}
 
@@ -100,7 +105,7 @@ func readPID() (int, error) {
 }
 
 func cleanupPID() {
-	os.Remove(pidFile)
+	_ = os.Remove(pidFile) // Ignore error - cleanup is best-effort
 }
 
 func isProcessRunning() bool {