Cline

Cline (formerly Claude Dev) is an open-source autonomous coding Agent extension for VS Code. The concept is similar to Claude Code, but it runs inside VS Code.

Key advantages: Support for third-party API relays is far better than Cursor, tool calls (read_file / write_to_file / execute_command) are stable, and it's especially well-suited to agentic workflows. It supports switching between multiple providers — Claude / OpenAI / Gemini / local models.

Learning curve: You need to understand the auto-approve risk (the Agent can run shell commands automatically). Beginners are advised to keep "Execute commands manual confirmation" enabled.

Who it's for: Developers who use VS Code rather than Cursor / the terminal; those who want to run long-chain agentic tasks but prefer to keep a traditional editor interaction.

This tutorial: Point Cline at claude-api.org inside VS Code and run Claude or the GPT-5 series.

A VS Code extension — an open-source autonomous coding Agent. More flexible than Cursor, but with a slightly steeper learning curve.

Recommended Channels

• Claude Official (any client) (2.0x): Cline recommends Claude by default (more stable tool calls), with good reliability. Claude Official (Claude Code only) (1.4x) will reject the Cline client.
• Budget Claude (0.5x): The lowest price, and it also accepts Cline, but quality / reliability is relatively unstable — choose it only if you can tolerate occasional failures.
• Claude Sonnet Discount (0.5x): If you mainly use Sonnet and want the cheapest option, the Sonnet discount group also accepts Cline, but it's limited to the Sonnet series of models.
• OpenAI: A backup. GPT-5.4 works too, but it occasionally gets stuck in tool loops.

Installation

VS Code → Extensions → search for "Cline" → Install.

Configuration

Click the Cline icon in the left activity bar → ⚙️ Settings:

配 Claude

API Provider:    Anthropic
API Key:         sk-你的key（绑 Claude Official (any client)）
Model:           claude-sonnet-4-6
Anthropic Base URL:  https://claude-api.org

配 OpenAI

API Provider:    OpenAI Compatible
API Key:         sk-你的key（绑 OpenAI）
Base URL:        https://claude-api.org/v1
Model ID:        gpt-5.4

"OpenAI Compatible" rather than "OpenAI"

Cline's "OpenAI" provider uses a special authentication flow (requiring you to log in to an OpenAI account). For a third-party relay, you must select "OpenAI Compatible".

Verification

Open any project in VS Code, click the Cline icon → send "List the files in the current directory".

If Cline calls a tool such as read_file and returns the listing, the setup was successful.

Advanced

Context window settings

By default, Cline reads entire files, so long projects easily hit the context limit. Settings → Context Window:

• Sonnet 4.6/4.7: enter 200000 (200K)
• Opus 4.7: enter 200000
• Sonnet 4.7[1m] (one-million context): enter 1000000, ⚠️ input price doubles

auto-approve toggles

Convenient but dangerous. We recommend at least keeping Execute commands requiring manual confirmation — Cline will run shell commands, and auto-approving them is like handing over your house.

FAQ

Persistent "Error: Connection error"

• Do not add /v1 to the end of the Anthropic Base URL; just write https://claude-api.org
• Check the Channel your Key is bound to: running Claude tasks requires a Claude-type Channel

Tool calls keep looping

• Switch to a Claude Channel (Anthropic's tool-use protocol is most stable in Cline)
• If you must use GPT-5: use the OpenAI Channel and use ChatCompletions(default) in the Cline configuration. Do not let Cline use the Responses API (the tool semantics differ)

Running out of balance mid-task

A Cline agentic task can consume $0.5–$5 at once (including context resends). We recommend a wallet Balance of at least $20 before starting an agent task.

For more, see FAQ.