feat: support [opik_cc] config section for plugin-scoped overrides

Make the ~/.opik.config parser section-aware so Claude Code workspace and
project overrides can live in a dedicated [opik_cc] section instead of the
awkward cc_workspace / cc_project_name keys under [opik].

SDK-shared values resolve from [opik] (with a top-level fallback for older
flat configs). The deprecated cc_* keys are still honored for backward
compatibility.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: jverre

README.md

@@ -66,18 +66,26 @@ All plugin env vars use the `OPIK_CC_` prefix to avoid conflicts with standard O
 `OPIK_CC_WORKSPACE` and `OPIK_CC_PROJECT` let you send Claude Code traces to a different
 workspace/project than the rest of your Opik setup, without touching the global
 `OPIK_WORKSPACE` / `project_name` in `~/.opik.config` used by the Opik SDK. Both can also be
-set in `~/.opik.config` via the plugin-scoped `cc_workspace` and `cc_project` keys:
+set in `~/.opik.config` via a dedicated `[opik_cc]` section, which keeps the plugin's settings
+separate from the SDK's `[opik]` section:
 
 ```ini
 [opik]
 workspace = my-sdk-workspace      # used by the Opik SDK
 project_name = my-sdk-project     # used by the Opik SDK
-cc_workspace = my-cc-workspace        # used only by the Claude Code plugin
-cc_project_name = my-cc-project       # used only by the Claude Code plugin
+
+[opik_cc]
+workspace = comet-all             # used only by the Claude Code plugin
+project_name = claude-code        # used only by the Claude Code plugin
 ```
 
-> Note: for backward compatibility, if `cc_project_name` is not set the plugin still falls back
-> to the shared `project_name` key.
+Resolution order (first match wins):
+
+- **Workspace:** `OPIK_CC_WORKSPACE` → `[opik_cc] workspace` → `[opik] cc_workspace` (deprecated) → `[opik] workspace` / `OPIK_WORKSPACE`
+- **Project:** `OPIK_CC_PROJECT` → `[opik_cc] project_name` → `[opik] cc_project_name` (deprecated) → `[opik] project_name` → `claude-code` (default)
+
+> Note: the deprecated `cc_workspace` / `cc_project_name` keys in the `[opik]` section are still
+> honored for backward compatibility, but new configs should use the `[opik_cc]` section.
 
 ### External Trace Linking
 

src/config.go

@@ -23,12 +23,14 @@ const truncateMsg = "[ TRUNCATED -- set OPIK_CC_TRUNCATE_FIELDS=false ]"
 
 func LoadConfig() (*Config, error) {
 	homeDir, _ := os.UserHomeDir()
-	var fileConfig map[string]string
+	var sections sectionedConfig
 	if homeDir != "" {
-		fileConfig = parseConfigFile(filepath.Join(homeDir, ".opik.config"))
+		sections = parseConfigFile(filepath.Join(homeDir, ".opik.config"))
 	}
 
-	url := getEnvOrConfig("OPIK_BASE_URL", fileConfig, "url_override")
+	// SDK-shared values live under the standard [opik] section (with a top-level
+	// fallback for older flat config files).
+	url := envOr("OPIK_BASE_URL", sections.opik("url_override"))
 	if url == "" {
 		return nil, nil
 	}
@@ -38,38 +40,77 @@ func LoadConfig() (*Config, error) {
 	cfg := &Config{
 		URL:           strings.TrimSuffix(url, "/") + "/v1/private",
 		Project:       "claude-code",
-		APIKey:        getEnvOrConfig("OPIK_API_KEY", fileConfig, "api_key"),
-		Workspace:     getEnvOrConfig("OPIK_WORKSPACE", fileConfig, "workspace"),
+		APIKey:        envOr("OPIK_API_KEY", sections.opik("api_key")),
+		Workspace:     envOr("OPIK_WORKSPACE", sections.opik("workspace")),
 		Debug:         os.Getenv("OPIK_CC_DEBUG") == "true" || tracing.debug,
 		Truncate:      os.Getenv("OPIK_CC_TRUNCATE_FIELDS") != "false",
 		Enabled:       tracing.enabled,
 		ParentTraceID: os.Getenv("OPIK_CC_PARENT_TRACE_ID"),
 		RootSpanID:    os.Getenv("OPIK_CC_ROOT_SPAN_ID"),
 	}
 
-	// OPIK_CC_PROJECT / cc_project are plugin-scoped and don't affect the Opik
-	// SDK. project_name is kept as a fallback for backward compatibility, but it
-	// is shared with the Opik SDK config in ~/.opik.config.
-	if proj := getEnvOrConfig("OPIK_CC_PROJECT", fileConfig, "cc_project_name"); proj != "" {
+	// Plugin-scoped project override. The [opik_cc] section keeps Claude Code
+	// settings separate from the SDK's [opik] section. Precedence:
+	//   OPIK_CC_PROJECT > [opik_cc] project_name > [opik] cc_project_name (deprecated)
+	//   > [opik] project_name (shared SDK fallback for backward compatibility)
+	if proj := os.Getenv("OPIK_CC_PROJECT"); proj != "" {
 		cfg.Project = proj
-	} else if proj := fileConfig["project_name"]; proj != "" {
+	} else if proj := sections.cc("project_name"); proj != "" {
+		cfg.Project = proj
+	} else if proj := sections.opik("cc_project_name"); proj != "" {
+		cfg.Project = proj
+	} else if proj := sections.opik("project_name"); proj != "" {
 		cfg.Project = proj
 	}
 
-	// Allow overriding the workspace for the Claude Code plugin only, without
-	// affecting the global OPIK_WORKSPACE / ~/.opik.config used by the Opik SDK.
-	if ws := getEnvOrConfig("OPIK_CC_WORKSPACE", fileConfig, "cc_workspace"); ws != "" {
+	// Plugin-scoped workspace override, so Claude Code traces can go to a
+	// different workspace without touching the global OPIK_WORKSPACE / [opik]
+	// workspace used by the Opik SDK. Precedence:
+	//   OPIK_CC_WORKSPACE > [opik_cc] workspace > [opik] cc_workspace (deprecated)
+	if ws := os.Getenv("OPIK_CC_WORKSPACE"); ws != "" {
+		cfg.Workspace = ws
+	} else if ws := sections.cc("workspace"); ws != "" {
+		cfg.Workspace = ws
+	} else if ws := sections.opik("cc_workspace"); ws != "" {
 		cfg.Workspace = ws
 	}
 
 	return cfg, nil
 }
 
-func parseConfigFile(path string) map[string]string {
-	result := make(map[string]string)
+// sectionedConfig holds the parsed ~/.opik.config keyed by INI section name.
+// Keys that appear before any [section] header are stored under "".
+type sectionedConfig map[string]map[string]string
+
+// value returns the key from the given section, or "" if absent.
+func (s sectionedConfig) value(section, key string) string {
+	if vals := s[section]; vals != nil {
+		return vals[key]
+	}
+	return ""
+}
+
+// opik resolves an SDK-shared key from the [opik] section, falling back to a
+// top-level key for older flat config files.
+func (s sectionedConfig) opik(key string) string {
+	if v := s.value("opik", key); v != "" {
+		return v
+	}
+	return s.value("", key)
+}
+
+// cc resolves a plugin-scoped key from the [opik_cc] section.
+func (s sectionedConfig) cc(key string) string {
+	return s.value("opik_cc", key)
+}
+
+func parseConfigFile(path string) sectionedConfig {
+	sections := sectionedConfig{"": {}}
+	current := sections[""]
+
 	file, err := os.Open(path)
 	if err != nil {
-		return result
+		return sections
 	}
 	defer file.Close()
 
@@ -79,18 +120,26 @@ func parseConfigFile(path string) map[string]string {
 		if line == "" || strings.HasPrefix(line, "#") {
 			continue
 		}
+		if strings.HasPrefix(line, "[") && strings.HasSuffix(line, "]") {
+			name := strings.TrimSpace(line[1 : len(line)-1])
+			if sections[name] == nil {
+				sections[name] = map[string]string{}
+			}
+			current = sections[name]
+			continue
+		}
 		if parts := strings.SplitN(line, "=", 2); len(parts) == 2 {
-			result[strings.TrimSpace(parts[0])] = strings.TrimSpace(parts[1])
+			current[strings.TrimSpace(parts[0])] = strings.TrimSpace(parts[1])
 		}
 	}
-	return result
+	return sections
 }
 
-func getEnvOrConfig(envVar string, fileConfig map[string]string, configKey string) string {
+func envOr(envVar, fallback string) string {
 	if val := os.Getenv(envVar); val != "" {
 		return val
 	}
-	return fileConfig[configKey]
+	return fallback
 }
 
 type tracingState struct {