Cline (Claude Code) / AI Coding Tools

Cline hits OpenAI native model reasoning/function_call pairing error during MCP tool use

Fix reasoning/function_call pairing errors when using GPT-5 series models through Cline MCP integration Includes evidence for Cline (Claude Code) troubleshooting demand.

Source-backed Last updated May 19, 2026 1 source Needs local verification

Category: AI Coding Tools
Error signature: reasoning/function_call pairing error during MCP/tool use on gpt-5.3-codex, gpt-5.4, gpt-5.5
Quick fix: Compare the failing environment with a known working setup, then change one configuration value at a time.
Updated: May 19, 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 Cline (Claude Code), 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

reasoning/function_call pairing error during MCP/tool use on gpt-5.3-codex, gpt-5.4, gpt-5.5 is a Cline (Claude Code) failure pattern reported for developers trying to fix reasoning/function_call pairing errors when using gpt-5 series models through cline mcp integration. Based on the imported evidence, treat this as a tool-specific troubleshooting page rather than a generic API error.

Why this happens

GitHub issue #10656 in cline/cline (opened May 12, 2026). Latest Cline versions encounter errors combining reasoning capabilities with function calls when using new GPT-5 models via MCP. Multiple comments indicate active user frustration with paid model features failing. Maps to 'AI Coding Tools'.

Common causes

GitHub issue #10656 in cline/cline (opened May 12, 2026). Latest Cline versions encounter errors combining reasoning capabilities with function calls when using new GPT-5 models via MCP. Multiple comments indicate active user frustration with paid model features failing. Maps to 'AI Coding Tools'.

Quick fixes

Confirm the exact error signature matches reasoning/function_call pairing error during MCP/tool use on gpt-5.3-codex, gpt-5.4, gpt-5.5.
Check the Cline (Claude Code) 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 reasoning/function_call pairing error during MCP/tool use on gpt-5.3-codex, gpt-5.4, gpt-5.5 exactly before applying the quick fix.
Compare the failing environment with Cline (Claude Code) 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 reasoning/function_call pairing error during MCP/tool use on gpt-5.3-codex, gpt-5.4, gpt-5.5 mean in Cline (Claude Code)?

reasoning/function_call pairing error during MCP/tool use on gpt-5.3-codex, gpt-5.4, gpt-5.5 indicates the workflow described by "Cline hits OpenAI native model reasoning/function_call pairing error during MCP tool use" failed in a AI Coding Tools context. Start by confirming the exact signature and the component that emitted it.

What should I check first for reasoning/function_call pairing error during MCP/tool use on gpt-5.3-codex, gpt-5.4, gpt-5.5?

Check whether this cause matches your environment: GitHub issue #10656 in cline/cline (opened May 12, 2026). Latest Cline versions encounter errors combining reasoning capabilities with function calls when using new GPT-5 models via MCP. Multiple comments indicate active user frustration with paid model features failing. Maps to 'AI Coding Tools'.

Is the reasoning/function_call pairing error during MCP/tool use on gpt-5.3-codex, gpt-5.4, gpt-5.5 guidance source-backed?

The "Cline hits OpenAI native model reasoning/function_call pairing error during MCP tool use" 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 reasoning/function_call pairing error during MCP/tool use on gpt-5.3-codex, gpt-5.4, gpt-5.5?

For "Cline hits OpenAI native model reasoning/function_call pairing error during MCP tool use", 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 reasoning/function_call pairing error during MCP/tool use on gpt-5.3-codex, gpt-5.4, gpt-5.5?

For "Cline hits OpenAI native model reasoning/function_call pairing error during MCP tool use", collect the failing Cline (Claude Code) command or request, non-secret configuration, versions, timestamps, request IDs when available, and the smallest reproduction that still triggers the signature.