LiteLLM / LiteLLM

LiteLLM Proxy Codex CLI Tool Calls Fail — gpt-5-codex Model Returns No Response

Fix LiteLLM proxy failing with OpenAI Codex CLI when using gpt-5-codex model with tool/function calls Includes evidence for LiteLLM troubleshooting demand.

Source-backed Last updated May 12, 2026 1 source Needs local verification

Category: LiteLLM
Error signature: Codex CLI does not respond correctly when using gpt-5-codex model with tool calls via LiteLLM proxy
Quick fix: Compare the failing environment with a known working setup, then change one configuration value at a time.
Updated: May 12, 2026
Verification status: Source-backed
Evidence: 1 public source URL

Before you change production

This page includes public source URLs in the imported troubleshooting record. Compare those references with your version and environment before applying changes.

Reproduce the smallest failing action and save non-secret logs before changing configuration.
Check versions for LiteLLM, related SDKs, package managers, CI runners, and hosting providers.
Change one setting or dependency at a time, then rerun the same failing command or request.
Avoid destructive commands, credential rotation, billing changes, or security relaxations without a rollback plan.

What this error means

Codex CLI does not respond correctly when using gpt-5-codex model with tool calls via LiteLLM proxy is a LiteLLM failure pattern reported for developers trying to fix litellm proxy failing with openai codex cli when using gpt-5-codex model with tool/function calls. Based on the imported evidence, treat this as a tool-specific troubleshooting page rather than a generic API error.

Why this happens

GitHub issue #14846: Codex CLI does not respond correctly with gpt-5-codex model via LiteLLM proxy. Simple prompts (e.g., 'Tell me a poem') work, but tool call requests (e.g., 'Explore this repository') fail. Video evidence provided showing both success and failure cases.

Common causes

When using LiteLLM proxy with OpenAI Codex CLI and gpt-5-codex model, tool call requests fail while simple prompts work. This indicates a LiteLLM proxy issue with tool/function call routing for the Codex model. Developers need to use LiteLLM as a unified gateway but this blocks Codex CLI workflows.
GitHub issue #14846: Codex CLI does not respond correctly with gpt-5-codex model via LiteLLM proxy. Simple prompts (e.g., 'Tell me a poem') work, but tool call requests (e.g., 'Explore this repository') fail. Video evidence provided showing both success and failure cases.

Quick fixes

Confirm the exact error signature matches Codex CLI does not respond correctly when using gpt-5-codex model with tool calls via LiteLLM proxy.
Check the LiteLLM account, local tool state, and provider configuration involved in the failing workflow.
Compare the failing environment with a known working setup, then change one configuration value at a time.

Platform/tool-specific checks

Verify the command, editor, extension, or API client that produced the error.
Compare local settings with CI, deployment, or editor-level settings when the error appears in only one environment.
Avoid deleting credentials, local model data, or project settings until the failing scope is clear.

Step-by-step troubleshooting

Capture the exact error message and the command, editor action, or request that triggered it.
Check whether the failure is account/auth, quota/rate, model/provider, local runtime, or deployment configuration.
Review the source evidence below and compare it with your environment.
Apply one change at a time and rerun the smallest failing action.
Keep the working fix documented for the team or deployment environment.

How to prevent it

Keep provider/tool configuration documented.
Record non-secret diagnostics such as tool version, provider name, model name, and command path.
Add a lightweight check before CI or production workflows depend on the tool.

Diagnostic flow for this page

Match Codex CLI does not respond correctly when using gpt-5-codex model with tool calls via LiteLLM proxy exactly before applying the quick fix.
Compare the failing environment with LiteLLM versions, account scope, provider settings, and deployment context.
Check the listed common causes in order, starting with the cause that best matches your logs.
Use the evidence status below to decide whether to confirm against public sources or official documentation.
Apply one reversible change, rerun the smallest failing action, and keep rollback notes.

FAQ

What does Codex CLI does not respond correctly when using gpt-5-codex model with tool calls via LiteLLM proxy mean in LiteLLM?

Codex CLI does not respond correctly when using gpt-5-codex model with tool calls via LiteLLM proxy indicates the workflow described by "LiteLLM Proxy Codex CLI Tool Calls Fail — gpt-5-codex Model Returns No Response" failed in a LiteLLM context. Start by confirming the exact signature and the component that emitted it.

What should I check first for Codex CLI does not respond correctly when using gpt-5-codex model with tool calls via LiteLLM proxy?

Check whether this cause matches your environment: When using LiteLLM proxy with OpenAI Codex CLI and gpt-5-codex model, tool call requests fail while simple prompts work. This indicates a LiteLLM proxy issue with tool/function call routing for the Codex model. Developers need to use LiteLLM as a unified gateway but this blocks Codex CLI workflows.

Is the Codex CLI does not respond correctly when using gpt-5-codex model with tool calls via LiteLLM proxy guidance source-backed?

The "LiteLLM Proxy Codex CLI Tool Calls Fail — gpt-5-codex Model Returns No Response" page is labeled source-backed. It has 1 public source URL from github.com, so use that evidence status when deciding how much additional verification you need.

When should I avoid the quick fix for Codex CLI does not respond correctly when using gpt-5-codex model with tool calls via LiteLLM proxy?

For "LiteLLM Proxy Codex CLI Tool Calls Fail — gpt-5-codex Model Returns No Response", avoid applying "Compare the failing environment with a known working setup, then change one configuration value at a time." when the error text differs, the affected version or provider is different, or the change would touch credentials, billing, DNS, production deploy settings, or irreversible data.

What should I collect before debugging Codex CLI does not respond correctly when using gpt-5-codex model with tool calls via LiteLLM proxy?

For "LiteLLM Proxy Codex CLI Tool Calls Fail — gpt-5-codex Model Returns No Response", collect the failing LiteLLM command or request, non-secret configuration, versions, timestamps, request IDs when available, and the smallest reproduction that still triggers the signature.