Writing, reviewing, editing, and answering questions about code is one of the primary use cases for OpenAI models today. This guide walks through your options for code generation with gpt-6-astra and Codex.
Codex is OpenAI’s coding agent for software development. It helps you write, review and debug code. Interact with Codex in a variety of interfaces: in your IDE, through the CLI, on web and mobile sites, or in your CI/CD pipelines with the SDK. Codex is the best way to get agentic software engineering on your projects.
Codex works best with the latest general-purpose models, such as gpt-6.1-sol.
See the ChatGPT docs for setup guides, reference material, pricing, and more information.
For most API-based code generation, start with gpt-6-astra. It handles both general-purpose work and coding, which makes it a strong default when your application needs to write code, reason about requirements, inspect docs, and handle broader workflows in one place.
This example shows how you can use the Responses API for a code generation use case:
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16import OpenAI from "openai";
const openai = new OpenAI();
const result = await openai.responses.create({
model: "gpt-6-astra",
input: `Find the null pointer exception in this code:
def display_name(user):
return user.profile.name
print(display_name(None))
`,
reasoning: { effort: "high" },
});
console.log(result.output_text);
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17from openai import OpenAI
client = OpenAI()
result = client.responses.create(
model="gpt-6-astra",
input="""Find the null pointer exception in this code:
def display_name(user):
return user.profile.name
print(display_name(None))
""",
reasoning={"effort": "high"},
)
print(result.output_text)
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28package main
import (
"context"
"fmt"
"github.com/openai/openai-go/v3"
"github.com/openai/openai-go/v3/responses"
"github.com/openai/openai-go/v3/shared"
)
func main() {
client := openai.NewClient()
response, err := client.Responses.New(context.Background(), responses.ResponseNewParams{
Model: "gpt-6-astra",
Input: responses.ResponseNewParamsInputUnion{OfString: openai.String(`Find the null pointer exception in this code:
def display_name(user):
return user.profile.name
print(display_name(None))`)},
Reasoning: shared.ReasoningParam{Effort: shared.ReasoningEffortHigh},
})
if err != nil {
panic(err)
}
fmt.Println(response.OutputText())
}
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26import com.openai.client.OpenAIClient;
import com.openai.client.okhttp.OpenAIOkHttpClient;
import com.openai.models.Reasoning;
import com.openai.models.ReasoningEffort;
import com.openai.models.responses.ResponseCreateParams;
String code =
"""
def display_name(user):
return user.profile.name
print(display_name(None))
""";
ResponseCreateParams params =
ResponseCreateParams.builder()
.model("gpt-6-astra")
.input("Find the null pointer exception in this code:\n\n" + code)
.reasoning(Reasoning.builder().effort(ReasoningEffort.HIGH).build())
.build();
client.responses().create(params).output().stream()
.flatMap(item -> item.message().stream())
.flatMap(message -> message.content().stream())
.flatMap(content -> content.outputText().stream())
.forEach(text -> System.out.println(text.text()));
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29using OpenAI.Responses;
#pragma warning disable OPENAI001
string key = Environment.GetEnvironmentVariable("OPENAI_API_KEY")!;
ResponsesClient client = new(key);
CreateResponseOptions options = new()
{
Model = "gpt-6-astra",
ReasoningOptions = new ResponseReasoningOptions
{
ReasoningEffortLevel = ResponseReasoningEffortLevel.High,
},
};
options.InputItems.Add(
ResponseItem.CreateUserMessageItem(
"""
Find the null pointer exception in this code:
def display_name(user):
return user.profile.name
print(display_name(None))
"""
)
);
ResponseResult response = await client.CreateResponseAsync(options);
Console.WriteLine(response.GetOutputText());
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17require "openai"
client = OpenAI::Client.new
code = <<~PYTHON
def display_name(user):
return user.profile.name
print(display_name(None))
PYTHON
response = client.responses.create(
model: "gpt-6-astra",
input: "Find the null pointer exception in this code:\n\n#{code}",
reasoning: { effort: :high }
)
puts(response.output_text)
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8curl https://api.openai.com/v1/responses \
-H "Content-Type: application/json" \
-H "Authorization: Bearer $OPENAI_API_KEY" \
-d '{
"model": "gpt-6-astra",
"input": "Find the null pointer exception in this code:\n\ndef display_name(user):\n return user.profile.name\n\nprint(display_name(None))\n",
"reasoning": { "effort": "high" }
}'
For frontend work, start with gpt-6.1-sol or gpt-6-astra in Codex or the Responses API.
The historical GPT-5 gallery shows applications generated from a single prompt. Use the prompts as starting points and evaluate the results with the model you plan to deploy.
- Visit the ChatGPT docs to learn what you can do with Codex, set up Codex in whichever interface you choose, or find more details.
- Read Model guidance for model selection, features, migration guidance, and prompting patterns that work well on coding and agentic tasks.
- Compare
gpt-6-astra and gpt-6.1-sol on the model pages.
