Show HN: Expose Copilot as a standard OpenAI-style API for your local toolchain

1 month ago 2

🛠️ Bring your Copilot subscription to your local toolchain

Copilot Bridge turns Visual Studio Code into a local OpenAI-compatible gateway to the GitHub Copilot access you already pay for. Point your favorite terminals, scripts, and desktop apps at the bridge and keep the chat experience you rely on inside the editor—without routing traffic to another vendor.

With the bridge running inside VS Code (the editor must stay open), every request stays on your machine while you:

Use Copilot from any CLI or automation — Curl it, cron it, or wire it into dev tooling that expects the OpenAI Chat Completions API.
Reuse existing OpenAI integrations — Swap the base URL and keep your Copilot responses flowing into the same workflows.
Stay in control — Keep latency low, keep traffic loopback-only, and gate access with an optional bearer token.

💡 How developers use Copilot Bridge

Script Copilot answers into local build helpers, documentation generators, or commit bots.
Experiment with agents and prompts while keeping requests on-device.
Trigger Copilot completions from Raycast, Alfred, or custom UI shells without leaving VS Code.

Local HTTP server bound to 127.0.0.1 by default
Fully OpenAI-style /v1/chat/completions, /v1/models, and /health endpoints
Server-Sent Events (SSE) streaming for fast, incremental responses
Real-time model discovery powered by the VS Code Language Model API
Concurrency guard with early 429 handling to keep your IDE responsive
Starts automatically with VS Code once enabled, so the bridge is always ready when you are

Important

⚖️ Usage note: Copilot Bridge extends your personal GitHub Copilot subscription. Use it in accordance with the existing Copilot and VS Code terms of service; you are responsible for staying compliant.

Visual Studio Code Desktop with GitHub Copilot signed in
(Optional for local builds) Node.js 18+ and npm

Install the extension from the Visual Studio Marketplace or side-load the latest .vsix.
In VS Code, press F5 to open an Extension Development Host if you're iterating locally.
Remember the bridge lives inside VS Code—keep the editor running when you want the HTTP endpoint online.
Enable the bridge:
- Command Palette → “Copilot Bridge: Enable”, or
- Set the bridge.enabled setting to true.
Check the status anytime via “Copilot Bridge: Status” to see the bound address, port, and auth requirements.

Note

Copilot Bridge stops listening as soon as VS Code closes. Keep the editor running whenever you need the endpoint available.

🏗️ Build from source (optional)

npm install npm run compile

Package a VSIX when you need to distribute a build:

Replace PORT with what “Copilot Bridge: Status” reports.

List models

curl http://127.0.0.1:$PORT/v1/models

Stream a completion

curl -N -H "Content-Type: application/json" \ -d '{"model":"gpt-4o-copilot","messages":[{"role":"user","content":"hello"}]}' \ http://127.0.0.1:$PORT/v1/chat/completions

Request a single JSON response

curl -H "Content-Type: application/json" \ -d '{"model":"gpt-4o-copilot","stream":false,"messages":[{"role":"user","content":"hello"}]}' \ http://127.0.0.1:$PORT/v1/chat/completions

Tip

You can also pass a family such as gpt-4o. If unavailable, the bridge returns 404 model_not_found.

💻 Use the OpenAI SDK (Node.js)

import OpenAI from "openai"; const client = new OpenAI({ baseURL: `http://127.0.0.1:${process.env.PORT}/v1`, apiKey: process.env.BRIDGE_TOKEN || "not-used-when-empty", }); const rsp = await client.chat.completions.create({ model: "gpt-4o-copilot", messages: [{ role: "user", content: "hello" }], stream: false, }); console.log(rsp.choices[0].message?.content);

🧠 Architecture at a glance

The extension invokes VS Code’s Language Model API to select an available GitHub Copilot chat model, normalizes your recent conversation turns, and forwards the request from a local Polka HTTP server. Responses are streamed back via SSE (or buffered when stream: false). The server respects concurrency limits so multiple calls won’t stall the editor.

GET /health — Reports IDE version, Copilot availability, and reason codes like missing_language_model_api.
GET /v1/models — Lists Copilot model IDs the bridge can access.
POST /v1/chat/completions — Accepts OpenAI-compatible bodies and streams deltas with a terminating data: [DONE] event.

Supported model values include IDs returned by /v1/models, Copilot families such as gpt-4o, or the keyword copilot for default selection. Common error responses: 401 unauthorized, 404 model_not_found, 429 rate_limit_exceeded, 503 copilot_unavailable.

ℹ️ OpenAI compatibility notes

Always returns a single choice (n = 1) and omits fields such as usage, service_tier, and system_fingerprint.
Treats tool_choice: "required" the same as "auto"; parallel_tool_calls is ignored because the VS Code API lacks those hooks.
Extra request options (logprobs, response_format, seed, metadata, store, etc.) are accepted but currently no-ops.
Streaming tool call deltas send complete JSON fragments; clients should replace previously received argument snippets.

⚙️ Configuration (bridge.*)

Settings appear under Copilot Bridge in VS Code settings:

Setting Default Description

bridge.enabled	false	Start the bridge automatically when VS Code launches.
bridge.host	127.0.0.1	Bind address. Keep it on loopback for safety.
bridge.port	0	HTTP port (0 requests an ephemeral port).
bridge.token	""	Optional bearer token enforced on every request.
bridge.historyWindow	3	User/assistant turns retained; system prompt is tracked separately.
bridge.maxConcurrent	1	Max simultaneous /v1/chat/completions; additional requests get 429.
bridge.verbose	false	Verbose logs in the “Copilot Bridge” Output channel.

Status bar: Copilot Bridge: OK @ 127.0.0.1:12345 (or similar) shows when the server is ready.

(Optional) Enable bridge.verbose.
Open View → Output → “Copilot Bridge”.
Trigger requests to inspect HTTP traces, model selection, SSE lifecycle, and health updates.

If Copilot or the Language Model API isn’t available, the output channel explains the reason along with the health status code.

Warning

Never expose the bridge to remote interfaces. It is intended for single-user, local workflows only.

Binds to 127.0.0.1 by default; do not expose it to remote interfaces.
Set bridge.token to require Authorization: Bearer <token> on each request.
Designed for single-user, local workflows and experiments.

/health may report copilot: "unavailable" with reason codes such as:

missing_language_model_api — VS Code API not available.
copilot_model_unavailable — No Copilot models selectable.
not_found — Requested model/family missing.
consent_required, rate_limited, copilot_unavailable — Provider-specific or transient issues.

POST /v1/chat/completions returns 503 with similar reasons when Copilot cannot handle the request.

Build once: npm run compile
Watch mode: npm run watch
Entry point: src/extension.ts

v1.1.0 — Simplified architecture with emphasis on faster inference (20–30% improvement).
v1.0.0 — Modular architecture refactor, OpenAI typings, and tool-calling support.
v0.2.2 — Polka HTTP integration and improved model family selection.
v0.1.5 — Server lifecycle fixes and enhanced error handling.
v0.1.4 — Dynamic Copilot model listing via the Language Model API.
v0.1.3 — Migration to the Language Model API with robust guards and reason codes.
v0.1.0 — Initial OpenAI-compatible bridge with SSE streaming.

🤝 Share ideas & contribute

Have an idea, found a bug, or thought of a new feature that should be supported next? Please open a new issue so we can track it together.

Apache-2.0

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Show HN: Expose Copilot as a standard OpenAI-style API for your local toolchain

🛠️ Bring your Copilot subscription to your local toolchain