GPT-models like GPT 5.4 from Github Copilot do not use reasoning

Related Claude implementation https://github.com/zed-industries/zed/pull/46540

### Reproduction steps

Works with OpenRouter but not with Copilot subscription

Just ask a question like "I want to wash my car. The car wash is 50 meters away. Should I walk or drive?"

## OpenRouter GPT 5.4

<img width="743" height="586" alt="Image" src="https://github.com/user-attachments/assets/9cd2d8b0-5135-4e81-a33f-b0d468bdba9e" />

## Copilot GPT 5.4

But Copilot does not think:

<img width="753" height="344" alt="Image" src="https://github.com/user-attachments/assets/3828265a-0751-4532-88fb-eddfcaa42043" />

## Opencode + Copilot

Also it would be nice to be able the set the reasoning level. Opencode gets this right with "high"

<img width="745" height="559" alt="Image" src="https://github.com/user-attachments/assets/9f05d7e0-b32d-4bf6-8282-72b2d67724ad" />

### Current vs. Expected behavior

GPT models should have thinking level effort options too like Opus:

<img width="459" height="133" alt="Image" src="https://github.com/user-attachments/assets/5cb880d2-5a0c-431a-b676-fa5ffbf76f9b" />

GPT:

<img width="473" height="133" alt="Image" src="https://github.com/user-attachments/assets/3617255d-fcb0-45b6-9d1d-d78c29659e98" />

### Zed version and system specs

Zed 0.228.0 
8421009ef8a022df1196d54bb42fd94366ec0988

0.228.0+stable.203.8421009ef8a022df1196d54bb42fd94366ec0988


Zed: v0.228.0+stable.203.8421009ef8a022df1196d54bb42fd94366ec0988 (Zed) 
OS: macOS 15.7.3
Memory: 36 GiB
Architecture: aarch64

### Attach Zed log file

<details><summary>Zed.log</summary>


```log

```

</details>


### Relevant Zed settings

I tried even setting `"enable_thinking": true,` in the settings.json but it makes no difference.

<details><summary>settings.json</summary>


```json
{
    "diff_view_style": "unified",
    "git_panel": {
        "dock": "right",
    },
    "outline_panel": {
        "dock": "right",
    },
    "file_scan_exclusions": ["**/rapidoc-min.js"],
    "colorize_brackets": false,
    "sticky_scroll": {
        "enabled": true,
    },
    // "use_system_window_tabs": true,
    "context_servers": {
        "mcp-server-context7": {
            "enabled": true,
            "settings": {
                "default_minimum_tokens": "10000",
            },
        },
    },
    "agent_servers": {
        "opencode": {
            "type": "registry",
        },
    },
    "bottom_dock_layout": "full",
    "edit_predictions": {
        "mode": "eager",
        "provider": "copilot",
    },
    "buffer_font_size": null,
    "language_models": {
        "ollama": { "api_url": "http://localhost:11434" },
        "openai_compatible": {
            "Z.ai": {
                "api_url": "https://api.z.ai/api/coding/paas/v4",
                "available_models": [
                    {
                        "name": "glm-4.7",
                        "display_name": "GLM-4.7",
                        "max_tokens": 200000,
                        "max_output_tokens": 128000,
                        "max_completion_tokens": 128000,
                        "capabilities": {
                            "tools": true,
                            "images": false,
                            "parallel_tool_calls": true,
                            "prompt_cache_key": true,
                        },
                    },
                ],
            },
        },
    },
    "preview_tabs": {
        "enabled": true,
        "enable_keep_preview_on_code_navigation": true,
    },
    "agent": {
        "tool_permissions": {
            "default": "allow",
        },
        "enable_feedback": false,
        "favorite_models": [
            {
                "provider": "copilot_chat",
                "model": "gpt-5.4",
                "enable_thinking": true,
            },
            {
                "provider": "copilot_chat",
                "model": "gpt-5-mini",
                "enable_thinking": false,
            },
            {
                "provider": "Z.ai",
                "model": "glm-4.7",
                "enable_thinking": false,
            },
            {
                "provider": "copilot_chat",
                "model": "claude-opus-4.6",
                "enable_thinking": true,
            },
        ],
        "dock": "left",
        "use_modifier_to_send": true,
        "play_sound_when_agent_done": true,
        "inline_assistant_model": {
            "provider": "copilot_chat",
            "model": "gpt-5.4",
        },
        "profiles": {
            "write": {
                "name": "Write",
                "tools": {
                    "copy_path": true,
                    "create_directory": true,
                    "delete_path": true,
                    "diagnostics": true,
                    "edit_file": true,
                    "fetch": true,
                    "list_directory": true,
                    "project_notifications": false,
                    "move_path": true,
                    "now": true,
                    "find_path": true,
                    "read_file": true,
                    "open": true,
                    "grep": true,
                    "terminal": true,
                    "thinking": true,
                    "web_search": true,
                },
                "enable_all_context_servers": true,
                "context_servers": {
                    "mcp-server-github": {
                        "tools": {
                            "add_comment_to_pending_review": false,
                        },
                    },
                },
            },
            "ask": {
                "name": "Ask",
                "tools": {
                    "contents": true,
                    "diagnostics": true,
                    "fetch": true,
                    "list_directory": true,
                    "now": true,
                    "find_path": true,
                    "read_file": true,
                    "open": true,
                    "grep": true,
                    "thinking": true,
                    "web_search": true,
                },
                "enable_all_context_servers": false,
                "context_servers": {},
            },
            "my-profile": {
                "name": "My profile",
                "tools": {
                    "copy_path": true,
                    "create_directory": true,
                    "create_file": true,
                    "delete_path": true,
                    "diagnostics": true,
                    "edit_file": true,
                    "fetch": true,
                    "list_directory": true,
                    "move_path": true,
                    "now": true,
                    "find_path": true,
                    "read_file": true,
                    "grep": true,
                    "terminal": true,
                    "thinking": true,
                    "web_search": true,
                },
                "enable_all_context_servers": true,
                "context_servers": {},
            },
        },
        "default_profile": "minimal",
        "default_model": {
            "effort": "high",
            "enable_thinking": false,
            "provider": "copilot_chat",
            "model": "gpt-5.4",
        },
    },
    "max_tabs": 50,
    "use_autoclose": false,
    "project_panel": { "dock": "right", "show_diagnostics": "errors" },
    "diagnostics": {
        "inline": {
            "enabled": false,
        },
    },
    "telemetry": {
        "metrics": false,
    },
    "file_types": {
        // "Nginx": ["cfg", "conf"]
    },
    // false because of https://github.com/zed-industries/zed/issues/11044#issuecomment-2579511499
    "ensure_final_newline_on_save": true,
    "remove_trailing_whitespace_on_save": true,
    "show_whitespaces": "selection",
    "terminal": {
        "option_as_meta": false,
        "env": {
            "GIT_EDITOR": "zed --wait",
        },
    },
    "restore_on_startup": "none",
    "auto_update": false,
    "theme": {
        "dark": "One Dark",
        "light": "One Light",
    },
    "tab_bar": {
        "show": true,
    },
    // "ui_font_family": "Zed Sans",
    "ui_font_family": "Intel One Mono",
    "buffer_font_family": "Intel One Mono",
    // "buffer_font_family": "JetBrains Mono",
    // "buffer_font_family": "OpenDyslexicMono",
    // "buffer_font_family": "UbuntuMono Nerd Font Mono",
    // "ui_font_family": "Comic Mono",
    // "buffer_font_family": "Comic Mono",
    "buffer_font_features": {
        "calt": false,
    },
    "vim_mode": true,
    "vim": {
        "use_system_clipboard": "never",
    },
    "git": {
        // "git_gutter": "tracked_files"
    },
    "inlay_hints": {
        "enabled": false,
    },
    "language_servers": [
        // "!tailwindcss-language-server",
        "!intelephense",
        "!typescript-language-server",
        "!graphql",
        "!taplo",
        "!nginx",
        "!vscode-css-language-server",
        "!vscode-html-language-server",
        "!vtsls",
        "...",
    ],
    "languages": {
        "SQL": {
            "format_on_save": "off",
        },
        "TypeScript": {
            "language_servers": ["vtsls", "..."],
        },
        "TSX": {
            "language_servers": ["vtsls", "..."],
        },
        "JavaScript": {
            "language_servers": ["vtsls", "..."],
        },
        "Nginx": {
            "tab_size": 4,
        },
        "Rust": {
            "language_servers": [
                "!typescript-language-server",
                "!vtsls",
                "rust-analyzer",
            ],
        },
        "YAML": {
            "auto_indent_on_paste": false,
            "format_on_save": "off",
            "tab_size": 2,
        },
    },
    //     "PHP": {
    //         "language_servers": [
    //             "phpactor",
    //             "!intelephense",
    //             "!tailwindcss-language-server",
    //             "..."
    //         ]
    //     }
    // },
    "lsp": {
        "vtsls": {
            "settings": {
                "typescript": {
                    "preferences": {
                        "importModuleSpecifier": "non-relative",
                    },
                },
            },
        },
        "rust-analyzer": {
            "initialization_options": {
                // https://rust-analyzer.github.io/book/configuration.html
                "cargo": {
                    // comment out to disable http
                    // "noDefaultFeatures": true,
                    // "features": []
                    // </comment>
                },
                "check": {
                    // "command": "clippy",
                    "command": "check",
                    "extraEnv": {
                        "RUSTFLAGS": "-A dead_code",
                    },
                },
            },
        },
    },
    "tab_size": 4,
}

```

</details>


### Relevant Keymap

<details><summary>keymap.json</summary>


```json

```

</details>


### (for AI issues) Model provider details

_No response_

### If you are using WSL on Windows, what flavor of Linux are you using?

None

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Uh oh!

GPT-models like GPT 5.4 from Github Copilot do not use reasoning #52140

Reproduction steps

OpenRouter GPT 5.4

Copilot GPT 5.4

Opencode + Copilot

Current vs. Expected behavior

Zed version and system specs

Attach Zed log file

Relevant Zed settings

Relevant Keymap

(for AI issues) Model provider details

If you are using WSL on Windows, what flavor of Linux are you using?

Metadata

Assignees

Labels

Type

Fields

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Milestone

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Development

Uh oh!

GPT-models like GPT 5.4 from Github Copilot do not use reasoning #52140

Description

Reproduction steps

OpenRouter GPT 5.4

Copilot GPT 5.4

Opencode + Copilot

Current vs. Expected behavior

Zed version and system specs

Attach Zed log file

Relevant Zed settings

Relevant Keymap

(for AI issues) Model provider details

If you are using WSL on Windows, what flavor of Linux are you using?

Metadata

Metadata

Assignees

Labels

Type

Fields

Projects

Milestone

Relationships

Development

Issue actions