diff --git a/README.md b/README.md
index 45ac231..7245d2a 100644
--- a/README.md
+++ b/README.md
@@ -16,7 +16,7 @@ Follow me on [X @nummanthinks](https://x.com/nummanthinks) for future updates an
 - ✅ **Smart auto-updating Codex instructions** - Tracks latest stable release with ETag caching
 - ✅ Full tool support (write, edit, bash, grep, etc.)
 - ✅ Automatic tool remapping (Codex tools → opencode tools)
-- ✅ High reasoning effort with detailed thinking blocks
+- ✅ Configurable reasoning effort and summaries (defaults: medium/auto)
 - ✅ Modular architecture for easy maintenance
 
 ## Installation
@@ -82,17 +82,151 @@ Select "OpenAI" and choose:
 ## Usage
 
 ```bash
-# Use gpt-5-codex with high reasoning (default)
+# Use gpt-5-codex with plugin defaults (medium/auto/medium)
 opencode run "create a hello world file" --model=openai/gpt-5-codex
 
-# Or set as default in opencode.json
-opencode run "solve this complex algorithm problem"
+# Or use regular gpt-5 via ChatGPT subscription
+opencode run "solve this complex problem" --model=openai/gpt-5
+
+# Set as default model in opencode.json
+opencode run "build a web app"
+```
+
+### Plugin Defaults
+
+When no configuration is specified, the plugin uses these defaults for all GPT-5 models:
+
+```json
+{
+  "reasoningEffort": "medium",
+  "reasoningSummary": "auto",
+  "textVerbosity": "medium"
+}
+```
+
+- **`reasoningEffort: "medium"`** - Balanced computational effort for reasoning
+- **`reasoningSummary: "auto"`** - Automatically adapts summary verbosity
+- **`textVerbosity: "medium"`** - Balanced output length
+
+These defaults match the official Codex CLI behavior and can be customized (see Configuration below).
+
+## Configuration
+
+You can customize model behavior for both `gpt-5` and `gpt-5-codex` models accessed via ChatGPT subscription.
+
+### Available Settings
+
+⚠️ **Important**: The two models have different supported values. Only use values listed in the tables below to avoid API errors.
+
+#### GPT-5 Model
+
+| Setting | Supported Values | Plugin Default | Description |
+|---------|-----------------|----------------|-------------|
+| `reasoningEffort` | `minimal`, `low`, `medium`, `high` | **`medium`** | Computational effort for reasoning |
+| `reasoningSummary` | `auto`, `detailed` | **`auto`** | Verbosity of reasoning summaries |
+| `textVerbosity` | `low`, `medium`, `high` | **`medium`** | Output length and detail level |
+
+#### GPT-5-Codex Model
+
+| Setting | Supported Values | Plugin Default | Description |
+|---------|-----------------|----------------|-------------|
+| `reasoningEffort` | `minimal`*, `low`, `medium`, `high` | **`medium`** | Computational effort for reasoning |
+| `reasoningSummary` | `auto`, `detailed` | **`auto`** | Verbosity of reasoning summaries |
+| `textVerbosity` | `medium` only | **`medium`** | Output length (codex only supports medium) |
+
+\* `minimal` is auto-normalized to `low` for gpt-5-codex
+
+#### Shared Settings (Both Models)
+
+| Setting | Values | Plugin Default | Description |
+|---------|--------|----------------|-------------|
+| `include` | Array of strings | `["reasoning.encrypted_content"]` | Additional response fields (for stateless reasoning) |
+
+### Configuration Examples
+
+#### Global Configuration
+
+Apply the same settings to all GPT-5 models:
+
+```json
+{
+  "$schema": "https://opencode.ai/config.json",
+  "plugin": ["opencode-openai-codex-auth"],
+  "model": "openai/gpt-5-codex",
+  "provider": {
+    "openai": {
+      "options": {
+        "reasoningEffort": "high",
+        "reasoningSummary": "detailed",
+        "textVerbosity": "medium"
+      }
+    }
+  }
+}
+```
+
+#### Per-Model Configuration
+
+Different settings for different models:
+
+```json
+{
+  "$schema": "https://opencode.ai/config.json",
+  "plugin": ["opencode-openai-codex-auth"],
+  "provider": {
+    "openai": {
+      "models": {
+        "gpt-5-codex": {
+          "options": {
+            "reasoningEffort": "high",
+            "reasoningSummary": "detailed",
+            "textVerbosity": "medium"
+          }
+        },
+        "gpt-5": {
+          "options": {
+            "reasoningEffort": "high",
+            "reasoningSummary": "detailed",
+            "textVerbosity": "low"
+          }
+        }
+      }
+    }
+  }
+}
+```
+
+#### Mixed Configuration
+
+Global defaults with per-model overrides:
+
+```json
+{
+  "$schema": "https://opencode.ai/config.json",
+  "plugin": ["opencode-openai-codex-auth"],
+  "model": "openai/gpt-5-codex",
+  "provider": {
+    "openai": {
+      "options": {
+        "reasoningEffort": "medium",
+        "reasoningSummary": "auto",
+        "textVerbosity": "medium"
+      },
+      "models": {
+        "gpt-5-codex": {
+          "options": {
+            "reasoningSummary": "detailed"
+          }
+        }
+      }
+    }
+  }
+}
 ```
 
-The plugin automatically configures:
-- **High reasoning effort** for deep thinking
-- **Detailed reasoning summaries** to show thought process
-- **Medium text verbosity** for balanced output
+In this example:
+- `gpt-5-codex` uses: `reasoningEffort: "medium"`, `reasoningSummary: "detailed"` (overridden), `textVerbosity: "medium"`
+- `gpt-5` uses all global defaults: `reasoningEffort: "medium"`, `reasoningSummary: "auto"`, `textVerbosity: "medium"`
 
 ## How It Works
 
@@ -111,13 +245,13 @@ The plugin:
 6. **Tool Remapping**: Injects instructions to map Codex tools to opencode tools:
    - `apply_patch` → `edit`
    - `update_plan` → `todowrite`
-7. **Reasoning Configuration**: Forces high reasoning effort with detailed summaries
-8. **History Filtering**: Removes stored conversation IDs since Codex uses `store: false`
+7. **Reasoning Configuration**: Defaults to medium effort and auto summaries (configurable per-model)
+8. **Encrypted Reasoning**: Includes encrypted reasoning content for stateless multi-turn conversations
+9. **History Filtering**: Removes stored conversation IDs since Codex uses `store: false`
 
 ## Limitations
 
 - **ChatGPT Plus/Pro required**: Must have an active ChatGPT Plus or Pro subscription
-- **Medium text verbosity**: Codex only supports `medium` for text verbosity
 
 ## Troubleshooting
 
diff --git a/index.mjs b/index.mjs
index 62a096a..1302876 100644
--- a/index.mjs
+++ b/index.mjs
@@ -21,9 +21,9 @@ export async function OpenAIAuthPlugin({ client }) {
 			provider: "openai",
 			/**
 			 * @param {() => Promise<any>} getAuth
-			 * @param {any} _provider
+			 * @param {any} provider - Provider configuration from opencode.json
 			 */
-			async loader(getAuth, _provider) {
+			async loader(getAuth, provider) {
 				const auth = await getAuth();
 
 				// Only handle OAuth auth type, skip API key auth
@@ -43,6 +43,13 @@ export async function OpenAIAuthPlugin({ client }) {
 					return {};
 				}
 
+				// Extract user configuration from provider structure
+				// Supports both global options and per-model options following Anthropic pattern
+				const userConfig = {
+					global: provider?.options || {},
+					models: provider?.models || {},
+				};
+
 				// Fetch Codex instructions (cached with ETag)
 				const CODEX_INSTRUCTIONS = await getCodexInstructions();
 
@@ -118,8 +125,8 @@ export async function OpenAIAuthPlugin({ client }) {
 									body,
 								});
 
-								// Transform request body for Codex API
-								body = transformRequestBody(body, CODEX_INSTRUCTIONS);
+								// Transform request body for Codex API with user configuration
+								body = transformRequestBody(body, CODEX_INSTRUCTIONS, userConfig);
 
 								// Log transformed request
 								logRequest("after-transform", {
@@ -130,6 +137,8 @@ export async function OpenAIAuthPlugin({ client }) {
 									hasInput: !!body.input,
 									inputLength: body.input?.length,
 									reasoning: body.reasoning,
+									textVerbosity: body.text?.verbosity,
+									include: body.include,
 									body,
 								});
 
diff --git a/lib/request-transformer.mjs b/lib/request-transformer.mjs
index 295075e..b8bbce8 100644
--- a/lib/request-transformer.mjs
+++ b/lib/request-transformer.mjs
@@ -19,17 +19,53 @@ export function normalizeModel(model) {
 }
 
 /**
- * Configure reasoning parameters based on model variant
+ * Extract configuration for a specific model
+ * Merges global options with model-specific options (model-specific takes precedence)
+ * @param {string} modelName - Model name (e.g., "gpt-5-codex")
+ * @param {object} userConfig - Full user configuration object
+ * @returns {object} Merged configuration for this model
+ */
+export function getModelConfig(modelName, userConfig = {}) {
+	const globalOptions = userConfig.global || {};
+	const modelOptions = userConfig.models?.[modelName]?.options || {};
+
+	// Model-specific options override global options
+	return { ...globalOptions, ...modelOptions };
+}
+
+/**
+ * Configure reasoning parameters based on model variant and user config
+ *
+ * NOTE: This plugin follows Codex CLI defaults instead of opencode defaults because:
+ * - We're accessing the ChatGPT backend API (not OpenAI Platform API)
+ * - opencode explicitly excludes gpt-5-codex from automatic reasoning configuration
+ * - Codex CLI has been thoroughly tested against this backend
+ *
  * @param {string} originalModel - Original model name before normalization
+ * @param {object} userConfig - User configuration object
  * @returns {object} Reasoning configuration
  */
-export function getReasoningConfig(originalModel) {
+export function getReasoningConfig(originalModel, userConfig = {}) {
 	const isLightweight =
 		originalModel?.includes("nano") || originalModel?.includes("mini");
+	const isCodex = originalModel?.includes("codex");
+
+	// Default based on model type (Codex CLI defaults)
+	const defaultEffort = isLightweight ? "minimal" : "medium";
+
+	// Get user-requested effort
+	let effort = userConfig.reasoningEffort || defaultEffort;
+
+	// Normalize "minimal" to "low" for gpt-5-codex
+	// Codex CLI does not provide a "minimal" preset for gpt-5-codex
+	// (only low/medium/high - see model_presets.rs:20-40)
+	if (isCodex && effort === "minimal") {
+		effort = "low";
+	}
 
 	return {
-		effort: isLightweight ? "minimal" : "high",
-		summary: "detailed", // Only supported value for gpt-5
+		effort,
+		summary: userConfig.reasoningSummary || "auto", // Changed from "detailed" to match Codex CLI
 	};
 }
 
@@ -75,15 +111,26 @@ export function addToolRemapMessage(input, hasTools) {
 
 /**
  * Transform request body for Codex API
+ *
+ * NOTE: Configuration follows Codex CLI patterns instead of opencode defaults:
+ * - opencode sets textVerbosity="low" for gpt-5, but Codex CLI uses "medium"
+ * - opencode excludes gpt-5-codex from reasoning configuration
+ * - This plugin uses store=false (stateless), requiring encrypted reasoning content
+ *
  * @param {object} body - Original request body
  * @param {string} codexInstructions - Codex system instructions
+ * @param {object} userConfig - User configuration from loader
  * @returns {object} Transformed request body
  */
-export function transformRequestBody(body, codexInstructions) {
+export function transformRequestBody(body, codexInstructions, userConfig = {}) {
 	const originalModel = body.model;
+	const normalizedModel = normalizeModel(body.model);
+
+	// Get model-specific configuration (merges global + per-model options)
+	const modelConfig = getModelConfig(normalizedModel, userConfig);
 
 	// Normalize model name
-	body.model = normalizeModel(body.model);
+	body.model = normalizedModel;
 
 	// Codex required fields
 	body.store = false;
@@ -96,19 +143,25 @@ export function transformRequestBody(body, codexInstructions) {
 		body.input = addToolRemapMessage(body.input, !!body.tools);
 	}
 
-	// Configure reasoning
-	const reasoningConfig = getReasoningConfig(originalModel);
+	// Configure reasoning (use model-specific config)
+	const reasoningConfig = getReasoningConfig(originalModel, modelConfig);
 	body.reasoning = {
 		...body.reasoning,
 		...reasoningConfig,
 	};
 
-	// Configure text verbosity
+	// Configure text verbosity (support user config)
+	// Default: "medium" (matches Codex CLI default for all GPT-5 models)
 	body.text = {
 		...body.text,
-		verbosity: "medium",
+		verbosity: modelConfig.textVerbosity || "medium",
 	};
 
+	// Add include for encrypted reasoning content
+	// Default: ["reasoning.encrypted_content"] (required for stateless operation with store=false)
+	// This allows reasoning context to persist across turns without server-side storage
+	body.include = modelConfig.include || ["reasoning.encrypted_content"];
+
 	// Remove unsupported parameters
 	body.max_output_tokens = undefined;
 	body.max_completion_tokens = undefined;
diff --git a/package.json b/package.json
index 812d5c5..8b0bf8d 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "opencode-openai-codex-auth",
-  "version": "1.0.3",
+  "version": "1.0.4",
   "description": "OpenAI ChatGPT (Codex backend) OAuth auth plugin for opencode - use your ChatGPT Plus/Pro subscription instead of API credits",
   "main": "./index.mjs",
   "type": "module",
diff --git a/test-config.json b/test-config.json
new file mode 100644
index 0000000..5a6a751
--- /dev/null
+++ b/test-config.json
@@ -0,0 +1,21 @@
+{
+  "$schema": "https://opencode.ai/config.json",
+  "plugin": ["file:///home/code/projects/ben-vargas/ai-opencode-openai-codex-auth/config-support"],
+  "model": "openai/gpt-5-codex",
+  "provider": {
+    "openai": {
+      "options": {
+        "reasoningEffort": "medium",
+        "reasoningSummary": "auto",
+        "textVerbosity": "medium"
+      },
+      "models": {
+        "gpt-5-codex": {
+          "options": {
+            "reasoningSummary": "concise"
+          }
+        }
+      }
+    }
+  }
+}
diff --git a/test-config.mjs b/test-config.mjs
new file mode 100755
index 0000000..1e6b51e
--- /dev/null
+++ b/test-config.mjs
@@ -0,0 +1,108 @@
+#!/usr/bin/env node
+import { getModelConfig, getReasoningConfig } from "./lib/request-transformer.mjs";
+
+console.log("=== Testing Configuration Parsing ===\n");
+
+// Simulate provider config from opencode.json
+const providerConfig = {
+	options: {
+		reasoningEffort: "medium",
+		reasoningSummary: "auto",
+		textVerbosity: "medium",
+	},
+	models: {
+		"gpt-5-codex": {
+			options: {
+				reasoningSummary: "concise", // Override global
+			},
+		},
+		"gpt-5": {
+			options: {
+				reasoningEffort: "high", // Override global
+			},
+		},
+	},
+};
+
+// Build userConfig structure (same as in index.mjs)
+const userConfig = {
+	global: providerConfig.options || {},
+	models: providerConfig.models || {},
+};
+
+console.log("Provider Config:");
+console.log(JSON.stringify(providerConfig, null, 2));
+console.log("\n");
+
+// Test 1: gpt-5-codex (should merge global + model-specific)
+console.log("Test 1: gpt-5-codex configuration");
+const codexConfig = getModelConfig("gpt-5-codex", userConfig);
+console.log("Merged config:", codexConfig);
+console.log("Expected: reasoningEffort='medium' (global), reasoningSummary='concise' (override), textVerbosity='medium' (global)");
+console.log("✓ Pass:", 
+	codexConfig.reasoningEffort === "medium" &&
+	codexConfig.reasoningSummary === "concise" &&
+	codexConfig.textVerbosity === "medium"
+);
+console.log("\n");
+
+// Test 2: gpt-5 (should merge global + model-specific)
+console.log("Test 2: gpt-5 configuration");
+const gpt5Config = getModelConfig("gpt-5", userConfig);
+console.log("Merged config:", gpt5Config);
+console.log("Expected: reasoningEffort='high' (override), reasoningSummary='auto' (global), textVerbosity='medium' (global)");
+console.log("✓ Pass:", 
+	gpt5Config.reasoningEffort === "high" &&
+	gpt5Config.reasoningSummary === "auto" &&
+	gpt5Config.textVerbosity === "medium"
+);
+console.log("\n");
+
+// Test 3: Reasoning config with user settings
+console.log("Test 3: Reasoning config for gpt-5-codex");
+const reasoningConfig = getReasoningConfig("gpt-5-codex", codexConfig);
+console.log("Reasoning config:", reasoningConfig);
+console.log("Expected: effort='medium', summary='concise'");
+console.log("✓ Pass:", 
+	reasoningConfig.effort === "medium" &&
+	reasoningConfig.summary === "concise"
+);
+console.log("\n");
+
+// Test 4: Defaults when no config provided
+console.log("Test 4: Defaults with empty config");
+const emptyConfig = getModelConfig("gpt-5-codex", {});
+const defaultReasoning = getReasoningConfig("gpt-5-codex", emptyConfig);
+console.log("Empty config:", emptyConfig);
+console.log("Default reasoning:", defaultReasoning);
+console.log("Expected: effort='medium' (default), summary='auto' (default)");
+console.log("✓ Pass:", 
+	defaultReasoning.effort === "medium" &&
+	defaultReasoning.summary === "auto"
+);
+console.log("\n");
+
+// Test 5: Lightweight model defaults
+console.log("Test 5: Lightweight model (gpt-5-nano)");
+const nanoReasoning = getReasoningConfig("gpt-5-nano", {});
+console.log("Nano reasoning:", nanoReasoning);
+console.log("Expected: effort='minimal' (lightweight default), summary='auto'");
+console.log("✓ Pass:",
+	nanoReasoning.effort === "minimal" &&
+	nanoReasoning.summary === "auto"
+);
+console.log("\n");
+
+// Test 6: Normalize "minimal" to "low" for gpt-5-codex
+console.log("Test 6: Normalize minimal→low for gpt-5-codex (Codex CLI doesn't support minimal)");
+const codexMinimalConfig = { reasoningEffort: "minimal" };
+const codexMinimalReasoning = getReasoningConfig("gpt-5-codex", codexMinimalConfig);
+console.log("Config:", codexMinimalConfig);
+console.log("Reasoning result:", codexMinimalReasoning);
+console.log("Expected: effort='low' (normalized from minimal), summary='auto'");
+console.log("✓ Pass:",
+	codexMinimalReasoning.effort === "low" &&
+	codexMinimalReasoning.summary === "auto"
+);
+
+console.log("\n=== All Tests Complete ===");