diff --git a/README.md b/README.md
index 4fd7f48..d720ec0 100644
--- a/README.md
+++ b/README.md
@@ -11,7 +11,7 @@
 A self-hosted AI workspace -- meant to be the self-hosted version of the UI experience you get from ChatGPT and Claude. But with more jank and fun. Running on your own hardware, with your own data -- local-first, privacy-first, and no trojan.
 
 ## Features
-  - **Chat** -- chat with any local model or API; adding them is super simple.<br>　<sub>vLLM · llama.cpp · Ollama · OpenRouter · OpenAI</sub>
+  - **Chat** -- chat with any local model or API; adding them is super simple.<br>　<sub>vLLM · llama.cpp · Ollama · OpenRouter · OpenAI · GitHub Copilot</sub>
   - **Agent** -- hand it tools and let it run the whole task itself.<br>　<sub>built on [opencode](https://github.com/anomalyco/opencode) · MCP · web · files · shell · skills · memory</sub>
   - **Cookbook** -- Scans your hardware, recommends models, click to download and serve.. easy!<br>　<sub>built on [llmfit](https://github.com/AlexsJones/llmfit) · VRAM-aware · GGUF / FP8 / AWQ · fit scoring · vLLM / llama.cpp serving</sub>
   - **Deep Research** -- multi-step runs that gather, read, and synthesize sources into a nice visual report.<br>　<sub>adapted from [Tongyi DeepResearch](https://github.com/Alibaba-NLP/DeepResearch)</sub>
diff --git a/app.py b/app.py
index 4160baf..4120be9 100644
--- a/app.py
+++ b/app.py
@@ -587,6 +587,10 @@ app.include_router(setup_embedding_routes())
 from routes.model_routes import setup_model_routes
 app.include_router(setup_model_routes(model_discovery))
 
+# GitHub Copilot device-flow login
+from routes.copilot_routes import setup_copilot_routes
+app.include_router(setup_copilot_routes())
+
 # TTS
 from routes.tts_routes import setup_tts_routes
 app.include_router(setup_tts_routes(tts_service))
diff --git a/routes/copilot_routes.py b/routes/copilot_routes.py
new file mode 100644
index 0000000..bb2b1d2
--- /dev/null
+++ b/routes/copilot_routes.py
@@ -0,0 +1,223 @@
+# routes/copilot_routes.py
+"""GitHub Copilot device-flow login.
+
+Drives the GitHub OAuth *device flow* and, on success, creates (or refreshes)
+an owner-scoped ``ModelEndpoint`` pointing at the Copilot API with the
+device-flow access token stored as its (encrypted) ``api_key``. After that the
+endpoint behaves like any other OpenAI-compatible provider — the Copilot-
+specific request headers are injected centrally by ``build_headers`` /
+``_provider_headers`` (see :mod:`src.copilot`).
+
+Flow:
+  1. ``POST /api/copilot/device/start`` → returns a ``poll_id`` plus the
+     ``user_code`` + ``verification_uri`` to show the user. The secret
+     ``device_code`` is kept server-side, never sent to the browser.
+  2. The browser polls ``POST /api/copilot/device/poll`` with ``poll_id``.
+     While pending it returns ``{status: "pending"}``; once the user authorises
+     it provisions the endpoint and returns ``{status: "authorized", ...}``.
+
+All routes are admin-gated (endpoint/provider management is an admin action).
+"""
+
+import json
+import time
+import uuid
+import logging
+import threading
+from typing import Dict, Optional
+
+import httpx
+from fastapi import APIRouter, Request, Form, HTTPException
+
+from core.database import SessionLocal, ModelEndpoint
+from core.middleware import require_admin
+from src.auth_helpers import get_current_user
+from src import copilot
+
+logger = logging.getLogger(__name__)
+
+# Pending device-flow logins, keyed by an opaque poll_id. The device_code is a
+# bearer-like secret, so it lives here (server memory) rather than in the
+# browser. Entries expire with the GitHub device code.
+#
+# NOTE: this is per-process state. The device flow assumes a single worker
+# (Odysseus' default): with multiple uvicorn workers, the poll request can land
+# on a worker that never saw the start, returning "Unknown or expired login
+# session". Move this to a shared store (DB/Redis) if running multi-worker.
+_PENDING: Dict[str, Dict] = {}
+_PENDING_LOCK = threading.Lock()
+
+
+def _prune_expired() -> None:
+    now = time.time()
+    with _PENDING_LOCK:
+        for k in [k for k, v in _PENDING.items() if v.get("expires_at", 0) < now]:
+            _PENDING.pop(k, None)
+
+
+def _provision_endpoint(token: str, base: str, owner: Optional[str]) -> Dict:
+    """Create or update the owner's Copilot endpoint with a fresh token."""
+    try:
+        models = copilot.fetch_models(base, token)
+    except Exception as e:
+        logger.warning(f"Copilot model fetch failed during provisioning: {e}")
+        models = []
+    model_ids = [m["id"] for m in models]
+    # Copilot picker models support OpenAI-style tool calling; mark the endpoint
+    # tool-capable so the agent loop sends native tool schemas.
+    # Tool-capable if any picker model advertises tool_calls. When the model
+    # fetch failed (empty list) default to True, since Copilot picker models
+    # support OpenAI-style tool calling.
+    supports_tools = bool(not models or any(m.get("tool_calls") for m in models))
+
+    db = SessionLocal()
+    try:
+        ep = (
+            db.query(ModelEndpoint)
+            .filter(ModelEndpoint.base_url == base)
+            .filter((ModelEndpoint.owner.is_(None)) | (ModelEndpoint.owner == owner))
+            .order_by(ModelEndpoint.owner.desc())
+            .first()
+        )
+        if ep is None:
+            ep = ModelEndpoint(
+                id=str(uuid.uuid4())[:8],
+                name="GitHub Copilot",
+                base_url=base,
+                model_type="llm",
+                owner=owner,
+            )
+            db.add(ep)
+        ep.api_key = token
+        ep.is_enabled = True
+        ep.supports_tools = supports_tools
+        if model_ids:
+            ep.cached_models = json.dumps(model_ids)
+        db.commit()
+        result = {
+            "id": ep.id,
+            "name": ep.name,
+            "base_url": ep.base_url,
+            "models": model_ids,
+        }
+    finally:
+        db.close()
+
+    # Best-effort: refresh the model cache so the new endpoint shows up.
+    try:
+        from routes.model_routes import _invalidate_models_cache
+        _invalidate_models_cache()
+    except Exception:
+        pass
+    return result
+
+
+def setup_copilot_routes() -> APIRouter:
+    router = APIRouter(prefix="/api/copilot", tags=["copilot"])
+
+    @router.post("/device/start")
+    def device_start(request: Request, enterprise_url: str = Form("")):
+        require_admin(request)
+        _prune_expired()
+        host = copilot.GITHUB_HOST
+        ent = (enterprise_url or "").strip()
+        if ent:
+            host = copilot.normalize_domain(ent)
+        try:
+            data = copilot.request_device_code(host)
+        except httpx.HTTPStatusError as e:
+            status = e.response.status_code if e.response is not None else "unknown"
+            raise HTTPException(502, f"GitHub device-code request failed (HTTP {status})")
+        except Exception as e:
+            raise HTTPException(502, f"GitHub device-code request failed: {e}")
+
+        device_code = data.get("device_code")
+        if not device_code:
+            raise HTTPException(502, "GitHub did not return a device code")
+        interval = int(data.get("interval") or 5)
+        expires_in = int(data.get("expires_in") or 900)
+        poll_id = uuid.uuid4().hex
+        with _PENDING_LOCK:
+            _PENDING[poll_id] = {
+                "device_code": device_code,
+                "host": host,
+                "enterprise_url": ent,
+                "interval": interval,
+                "owner": get_current_user(request) or None,
+                "expires_at": time.time() + expires_in,
+                "next_poll_at": 0.0,
+            }
+        # verification_uri_complete embeds the user code, so the browser tab we
+        # open lands the user straight on GitHub's "Authorize" screen with the
+        # code pre-filled — one click, no manual code entry.
+        return {
+            "poll_id": poll_id,
+            "user_code": data.get("user_code"),
+            "verification_uri": data.get("verification_uri"),
+            "verification_uri_complete": data.get("verification_uri_complete"),
+            "interval": interval,
+            "expires_in": expires_in,
+        }
+
+    @router.post("/device/poll")
+    def device_poll(request: Request, poll_id: str = Form(...)):
+        require_admin(request)
+        _prune_expired()
+        with _PENDING_LOCK:
+            pending = _PENDING.get(poll_id)
+        if not pending:
+            raise HTTPException(404, "Unknown or expired login session")
+
+        # Enforce GitHub's polling interval server-side so a chatty client
+        # can't trip slow_down.
+        now = time.time()
+        if now < pending.get("next_poll_at", 0):
+            return {"status": "pending"}
+
+        try:
+            data = copilot.poll_access_token(pending["host"], pending["device_code"])
+        except Exception as e:
+            return {"status": "pending", "detail": f"poll error: {e}"}
+
+        token = data.get("access_token")
+        if token:
+            base = copilot.enterprise_base(pending["enterprise_url"]) if pending["enterprise_url"] else copilot.COPILOT_BASE
+            try:
+                result = _provision_endpoint(token, base, pending["owner"])
+            except Exception as e:
+                logger.exception("Copilot endpoint provisioning failed")
+                with _PENDING_LOCK:
+                    _PENDING.pop(poll_id, None)
+                raise HTTPException(500, f"Login succeeded but provisioning failed: {e}")
+            with _PENDING_LOCK:
+                _PENDING.pop(poll_id, None)
+            return {"status": "authorized", "endpoint": result}
+
+        err = data.get("error")
+        if err == "authorization_pending":
+            with _PENDING_LOCK:
+                if poll_id in _PENDING:
+                    _PENDING[poll_id]["next_poll_at"] = now + pending["interval"]
+            return {"status": "pending"}
+        if err == "slow_down":
+            new_interval = int(data.get("interval") or (pending["interval"] + 5))
+            with _PENDING_LOCK:
+                if poll_id in _PENDING:
+                    _PENDING[poll_id]["interval"] = new_interval
+                    _PENDING[poll_id]["next_poll_at"] = now + new_interval
+            return {"status": "pending"}
+        if err in ("expired_token", "access_denied"):
+            with _PENDING_LOCK:
+                _PENDING.pop(poll_id, None)
+            return {"status": "failed", "error": err}
+        # Unknown error — surface but keep the session for another try.
+        return {"status": "pending", "detail": err or "unknown"}
+
+    @router.post("/device/cancel")
+    def device_cancel(request: Request, poll_id: str = Form(...)):
+        require_admin(request)
+        with _PENDING_LOCK:
+            _PENDING.pop(poll_id, None)
+        return {"status": "cancelled"}
+
+    return router
diff --git a/src/agent_loop.py b/src/agent_loop.py
index d6d9370..7aa7e19 100644
--- a/src/agent_loop.py
+++ b/src/agent_loop.py
@@ -468,6 +468,7 @@ _API_HOSTS = frozenset([
     "api.together.xyz", "api.fireworks.ai",
     "api.perplexity.ai", "api.x.ai",
     "ollama.com", "api.venice.ai",
+    "api.githubcopilot.com",
     # Local OpenAI-compatible endpoints (llama.cpp, vLLM, LM Studio, etc.).
     # Without these, `_is_api_model` falls back to keyword sniffing on the
     # model name, so well-behaved local servers don't get native tool
diff --git a/src/copilot.py b/src/copilot.py
new file mode 100644
index 0000000..62d2b8c
--- /dev/null
+++ b/src/copilot.py
@@ -0,0 +1,253 @@
+# src/copilot.py
+"""GitHub Copilot provider support.
+
+Copilot exposes an OpenAI-compatible API at ``https://api.githubcopilot.com``
+(``/chat/completions`` + ``/models``). Authentication is a GitHub OAuth
+**device flow**: the user authorises a device code in their browser and we
+receive a long-lived ``access_token`` that is sent directly as
+``Authorization: Bearer <token>`` — there is no separate Copilot-token
+exchange and no refresh (mirrors how editors / opencode talk to Copilot).
+
+The only provider-specific wrinkle beyond the bearer token is a handful of
+required request headers (API version, intent, an editor-style User-Agent,
+and ``x-initiator`` for agent-vs-user request accounting). Those live in
+:func:`copilot_headers`.
+
+This module holds the constants + pure helpers; the HTTP device-flow calls
+live in :mod:`routes.copilot_routes` so they can be auth-gated.
+"""
+
+import os
+from typing import Dict, List, Optional
+from urllib.parse import urlparse
+
+import httpx
+
+# ---------------------------------------------------------------------------
+# Constants
+# ---------------------------------------------------------------------------
+
+# GitHub OAuth client id used for the device flow. Copilot's token endpoint
+# only accepts client ids that GitHub has allow-listed for Copilot access, so
+# we reuse the public VS Code client id (the de-facto standard third-party
+# clients use). Override via env if you register your own allow-listed app.
+COPILOT_CLIENT_ID = os.environ.get(
+    "ODYSSEUS_COPILOT_CLIENT_ID", "01ab8ac9400c4e429b23"
+)
+
+# Dated API version header required by the Copilot API (models + chat).
+COPILOT_API_VERSION = os.environ.get(
+    "ODYSSEUS_COPILOT_API_VERSION", "2026-06-01"
+)
+
+# Public Copilot API base. GitHub Enterprise uses ``copilot-api.<domain>``.
+COPILOT_BASE = "https://api.githubcopilot.com"
+
+# Copilot wants an editor-like User-Agent + integration id. These identify the
+# client to GitHub; keep them stable.
+COPILOT_USER_AGENT = os.environ.get(
+    "ODYSSEUS_COPILOT_USER_AGENT", "Odysseus/1.0"
+)
+COPILOT_INTEGRATION_ID = os.environ.get(
+    "ODYSSEUS_COPILOT_INTEGRATION_ID", "vscode-chat"
+)
+COPILOT_EDITOR_VERSION = os.environ.get(
+    "ODYSSEUS_COPILOT_EDITOR_VERSION", "Odysseus/1.0"
+)
+
+# OAuth scope requested during the device flow.
+COPILOT_SCOPE = "read:user"
+
+# Default GitHub host for the device flow (public github.com).
+GITHUB_HOST = "github.com"
+
+
+def device_code_url(host: str = GITHUB_HOST) -> str:
+    return f"https://{host}/login/device/code"
+
+
+def access_token_url(host: str = GITHUB_HOST) -> str:
+    return f"https://{host}/login/oauth/access_token"
+
+
+def normalize_domain(url: str) -> str:
+    """Strip scheme/trailing slash from a GitHub Enterprise URL or domain."""
+    return (url or "").replace("https://", "").replace("http://", "").rstrip("/")
+
+
+def enterprise_base(enterprise_url: Optional[str]) -> str:
+    """Return the Copilot API base for a deployment.
+
+    Public github.com → ``https://api.githubcopilot.com``.
+    Enterprise <domain> → ``https://copilot-api.<domain>``.
+    """
+    if not enterprise_url:
+        return COPILOT_BASE
+    return f"https://copilot-api.{normalize_domain(enterprise_url)}"
+
+
+def is_copilot_base(url: Optional[str]) -> bool:
+    """True if a base URL points at the Copilot API (public or enterprise)."""
+    if not url:
+        return False
+    try:
+        host = (urlparse(url).hostname or "").lower().rstrip(".")
+    except Exception:
+        return False
+    if not host:
+        return False
+    # Public: api.githubcopilot.com (or any *.githubcopilot.com).
+    if host == "githubcopilot.com" or host.endswith(".githubcopilot.com"):
+        return True
+    # Enterprise: copilot-api.<domain>.
+    if host.startswith("copilot-api."):
+        return True
+    return False
+
+
+def copilot_headers(
+    api_key: Optional[str],
+    *,
+    agent: bool = False,
+    vision: bool = False,
+) -> Dict[str, str]:
+    """Build the Copilot-specific request headers.
+
+    Args:
+        api_key: the GitHub device-flow access token (sent as Bearer).
+        agent:   request originates from the agent loop (a tool-driven turn)
+                 rather than a direct user message. Sets ``x-initiator`` for
+                 Copilot's agent-vs-user request accounting.
+        vision:  the request carries an image part.
+    """
+    headers: Dict[str, str] = {
+        "X-GitHub-Api-Version": COPILOT_API_VERSION,
+        "Openai-Intent": "conversation-edits",
+        "User-Agent": COPILOT_USER_AGENT,
+        "Editor-Version": COPILOT_EDITOR_VERSION,
+        "Copilot-Integration-Id": COPILOT_INTEGRATION_ID,
+        "x-initiator": "agent" if agent else "user",
+    }
+    if api_key:
+        headers["Authorization"] = f"Bearer {api_key}"
+    if vision:
+        headers["Copilot-Vision-Request"] = "true"
+    return headers
+
+
+# ---------------------------------------------------------------------------
+# Device-flow OAuth (pure HTTP; orchestration lives in routes.copilot_routes)
+# ---------------------------------------------------------------------------
+
+def _oauth_post_headers() -> Dict[str, str]:
+    return {
+        "Accept": "application/json",
+        "Content-Type": "application/json",
+        "User-Agent": COPILOT_USER_AGENT,
+    }
+
+
+def request_device_code(host: str = GITHUB_HOST, *, timeout: float = 10.0) -> Dict:
+    """Start the device flow. Returns GitHub's
+    ``{device_code, user_code, verification_uri, expires_in, interval}``.
+    """
+    r = httpx.post(
+        device_code_url(host),
+        headers=_oauth_post_headers(),
+        json={"client_id": COPILOT_CLIENT_ID, "scope": COPILOT_SCOPE},
+        timeout=timeout,
+    )
+    r.raise_for_status()
+    return r.json()
+
+
+def poll_access_token(host: str, device_code: str, *, timeout: float = 10.0) -> Dict:
+    """Poll once for the access token. GitHub returns HTTP 200 with an
+    ``error`` field (``authorization_pending``/``slow_down``) while the user
+    hasn't authorised yet, or ``{access_token, ...}`` once they have.
+    """
+    r = httpx.post(
+        access_token_url(host),
+        headers=_oauth_post_headers(),
+        json={
+            "client_id": COPILOT_CLIENT_ID,
+            "device_code": device_code,
+            "grant_type": "urn:ietf:params:oauth:grant-type:device_code",
+        },
+        timeout=timeout,
+    )
+    r.raise_for_status()
+    return r.json()
+
+
+def fetch_models(base: str, token: str, *, timeout: float = 15.0) -> List[Dict]:
+    """Fetch Copilot's model catalogue, filtered to picker-enabled models.
+
+    Returns a list of ``{id, tool_calls, vision}`` dicts. Falls back to the
+    full list if no model advertises ``model_picker_enabled`` (defensive
+    against API-shape drift).
+    """
+    url = base.rstrip("/") + "/models"
+    r = httpx.get(url, headers=copilot_headers(token), timeout=timeout)
+    r.raise_for_status()
+    data = (r.json() or {}).get("data") or []
+
+    def _parse(item: Dict) -> Optional[Dict]:
+        mid = item.get("id")
+        if not mid:
+            return None
+        supports = ((item.get("capabilities") or {}).get("supports")) or {}
+        return {
+            "id": mid,
+            "tool_calls": bool(supports.get("tool_calls")),
+            "vision": bool(supports.get("vision")),
+            "picker": bool(item.get("model_picker_enabled")),
+        }
+
+    parsed = [p for p in (_parse(it) for it in data) if p]
+    picker = [p for p in parsed if p["picker"]]
+    chosen = picker or parsed
+    for p in chosen:
+        p.pop("picker", None)
+    return chosen
+
+
+# ---------------------------------------------------------------------------
+# Per-request header flags
+# ---------------------------------------------------------------------------
+
+_IMAGE_PART_TYPES = ("image_url", "input_image", "image")
+
+
+def request_flags(messages) -> tuple:
+    """Derive ``(agent, vision)`` from an OpenAI-style message list.
+
+    Mirrors opencode's logic:
+      * ``agent`` — the last message is *not* a plain user message (i.e. it's a
+        tool result / assistant follow-up), so Copilot should treat the request
+        as agent-initiated for request accounting.
+      * ``vision`` — any message carries an image content part.
+    """
+    msgs = messages or []
+    last = msgs[-1] if msgs else None
+    agent = bool(last) and last.get("role") != "user"
+    vision = False
+    for m in msgs:
+        content = m.get("content") if isinstance(m, dict) else None
+        if isinstance(content, list) and any(
+            isinstance(p, dict) and p.get("type") in _IMAGE_PART_TYPES for p in content
+        ):
+            vision = True
+            break
+    return agent, vision
+
+
+def apply_request_headers(headers: Dict[str, str], messages) -> Dict[str, str]:
+    """Set ``x-initiator`` / ``Copilot-Vision-Request`` on a header dict based
+    on the outgoing messages. Mutates and returns ``headers``."""
+    agent, vision = request_flags(messages)
+    headers["x-initiator"] = "agent" if agent else "user"
+    if vision:
+        headers["Copilot-Vision-Request"] = "true"
+    return headers
+
diff --git a/src/endpoint_resolver.py b/src/endpoint_resolver.py
index 073f8d7..a9ab5c7 100644
--- a/src/endpoint_resolver.py
+++ b/src/endpoint_resolver.py
@@ -194,6 +194,9 @@ def build_headers(api_key: Optional[str], base: str) -> Dict[str, str]:
             headers["x-api-key"] = api_key
         headers["anthropic-version"] = "2023-06-01"
         return headers
+    if provider == "copilot":
+        from src.copilot import copilot_headers
+        return copilot_headers(api_key)
     if api_key:
         headers["Authorization"] = f"Bearer {api_key}"
     if provider == "openrouter":
diff --git a/src/llm_core.py b/src/llm_core.py
index 1baf184..092384b 100644
--- a/src/llm_core.py
+++ b/src/llm_core.py
@@ -317,6 +317,9 @@ def _detect_provider(url: str) -> str:
         return "openrouter"
     if _host_match(url, "groq.com"):
         return "groq"
+    from src.copilot import is_copilot_base
+    if is_copilot_base(url):
+        return "copilot"
     return "openai"
 
 
@@ -327,6 +330,14 @@ def _provider_headers(provider: str, headers: Optional[Dict] = None) -> Dict[str
     if provider == "openrouter":
         h.setdefault("HTTP-Referer", "https://github.com/pewdiepie-archdaemon/odysseus")
         h.setdefault("X-OpenRouter-Title", "Odysseus")
+    if provider == "copilot":
+        # Ensure the Copilot-required headers are present even when the caller
+        # didn't pass pre-built headers (e.g. model listing). build_headers()
+        # already injects these for the live chat path; setdefault keeps any
+        # request-specific values (x-initiator/vision) the caller set.
+        from src.copilot import copilot_headers
+        for k, v in copilot_headers(None).items():
+            h.setdefault(k, v)
     return h
 
 
@@ -340,6 +351,8 @@ def _provider_label(url: str) -> str:
     if _host_match(url, "openai.com"): return "OpenAI"
     if _host_match(url, "openrouter.ai"): return "OpenRouter"
     if _host_match(url, "groq.com"): return "Groq"
+    from src.copilot import is_copilot_base
+    if is_copilot_base(url): return "GitHub Copilot"
     if _host_match(url, "mistral.ai"): return "Mistral"
     if _host_match(url, "deepseek.com"): return "DeepSeek"
     if _host_match(url, "googleapis.com"): return "Google"
@@ -911,6 +924,9 @@ def llm_call(url: str, model: str, messages: List[Dict], temperature: float = LL
         )
     else:
         target_url = url
+        if provider == "copilot":
+            from src.copilot import apply_request_headers
+            apply_request_headers(h, messages_copy)
         payload = {
             "model": model,
             "messages": messages_copy,
@@ -1058,6 +1074,9 @@ async def llm_call_async(
     else:
         target_url = url
         h = _provider_headers(provider, headers)
+        if provider == "copilot":
+            from src.copilot import apply_request_headers
+            apply_request_headers(h, messages_copy)
         payload = {
             "model": model,
             "messages": messages_copy,
@@ -1182,6 +1201,9 @@ async def stream_llm(url: str, model: str, messages: List[Dict], temperature: fl
         if tools:
             payload["tools"] = tools
         h = _provider_headers(provider, headers)
+        if provider == "copilot":
+            from src.copilot import apply_request_headers
+            apply_request_headers(h, messages_copy)
 
     # Short connect timeout: a reachable peer answers SYN in <100ms even on
     # Tailscale. 3s is plenty; 30s let one dead upstream wedge the UI.
diff --git a/src/model_context.py b/src/model_context.py
index c985d3d..2fd0b82 100644
--- a/src/model_context.py
+++ b/src/model_context.py
@@ -282,6 +282,16 @@ def _query_context_length(endpoint_url: str, model: str) -> int:
         except Exception:
             pass
 
+    # GitHub Copilot's /models requires auth + X-GitHub-Api-Version headers that
+    # aren't available here; an unauthenticated probe just 400s. All Copilot
+    # picker models are major API models covered by the known-context table, so
+    # rely on that instead of a doomed network call.
+    from src.copilot import is_copilot_base
+    if is_copilot_base(endpoint_url):
+        if known:
+            logger.info(f"Using known context window for {model}: {known}")
+        return known or DEFAULT_CONTEXT
+
     models_url = endpoint_url.replace("/chat/completions", "/models")
     try:
         r = httpx.get(models_url, timeout=REQUEST_TIMEOUT)
diff --git a/static/index.html b/static/index.html
index fadb0c6..cade5cf 100644
--- a/static/index.html
+++ b/static/index.html
@@ -2092,6 +2092,13 @@
                   <button class="admin-btn-add" id="adm-epAddBtn" style="width:55px;text-align:center;">Add</button>
                 </div>
                 <div id="adm-epApiMsg" class="adm-ep-inline-msg"></div>
+                <div class="adm-copilot-connect">
+                  <button class="admin-btn-sm" id="adm-copilotConnectBtn" type="button" title="Sign in to GitHub Copilot via device flow">
+                    <svg width="13" height="13" viewBox="0 0 24 24" fill="currentColor" style="vertical-align:-2px;margin-right:5px;opacity:0.8"><path d="M12 .5C5.7.5.5 5.7.5 12c0 5.1 3.3 9.4 7.9 10.9.6.1.8-.2.8-.5v-1.7c-3.2.7-3.9-1.5-3.9-1.5-.5-1.3-1.3-1.7-1.3-1.7-1.1-.7.1-.7.1-.7 1.2.1 1.8 1.2 1.8 1.2 1 1.8 2.7 1.3 3.4 1 .1-.8.4-1.3.7-1.6-2.6-.3-5.3-1.3-5.3-5.7 0-1.3.4-2.3 1.2-3.1-.1-.3-.5-1.5.1-3.1 0 0 1-.3 3.3 1.2a11.4 11.4 0 0 1 6 0C17.3 4.7 18.3 5 18.3 5c.6 1.6.2 2.8.1 3.1.8.8 1.2 1.8 1.2 3.1 0 4.4-2.7 5.4-5.3 5.7.4.4.8 1.1.8 2.2v3.3c0 .3.2.6.8.5 4.6-1.5 7.9-5.8 7.9-10.9C23.5 5.7 18.3.5 12 .5z"/></svg>
+                    Connect GitHub Copilot
+                  </button>
+                  <div id="adm-copilotStatus" class="adm-ep-inline-msg"></div>
+                </div>
               </div>
             </div>
           </div>
diff --git a/static/js/admin.js b/static/js/admin.js
index 2c2ceae..25e3faa 100644
--- a/static/js/admin.js
+++ b/static/js/admin.js
@@ -912,6 +912,78 @@ function initEndpointForm() {
     btn.disabled = false; btn.textContent = 'Add';
   });
 
+  // GitHub Copilot — device-flow login. Starts the flow, shows the user a
+  // code + verification link, and polls until they authorise (or it expires).
+  const copilotBtn = el('adm-copilotConnectBtn');
+  if (copilotBtn) {
+    let copilotPolling = false;
+    copilotBtn.addEventListener('click', async () => {
+      if (copilotPolling) return;
+      const status = el('adm-copilotStatus');
+      const reset = () => { copilotBtn.disabled = false; copilotBtn.textContent = 'Connect GitHub Copilot'; copilotPolling = false; };
+      status.textContent = ''; status.className = 'adm-ep-inline-msg';
+      copilotBtn.disabled = true; copilotBtn.textContent = 'Starting...';
+      copilotPolling = true;
+      let start;
+      try {
+        const res = await fetch('/api/copilot/device/start', { method: 'POST', body: new FormData(), credentials: 'same-origin' });
+        start = await res.json();
+        if (!res.ok) { status.textContent = start.detail || 'Failed to start login'; status.className = 'admin-error'; reset(); return; }
+      } catch (e) { status.textContent = 'Request failed'; status.className = 'admin-error'; reset(); return; }
+
+      const { poll_id, user_code, verification_uri, verification_uri_complete, interval, expires_in } = start;
+      // Prefer the "complete" URL — it embeds the code so the user only has to
+      // click "Authorize" (no manual code entry).
+      const authUrl = verification_uri_complete || verification_uri || '';
+      const esc = (s) => String(s || '').replace(/[<>&"]/g, (c) => ({ '<': '&lt;', '>': '&gt;', '&': '&amp;', '"': '&quot;' }[c]));
+      copilotBtn.textContent = 'Waiting…';
+
+      // Cohesive waiting panel: spinner + status line, the device code as a
+      // copyable chip, and a primary "Authorize on GitHub" action.
+      status.className = '';
+      status.innerHTML =
+        '<div class="adm-copilot-panel">' +
+          '<div class="adm-copilot-wait"><span class="admin-spinner"></span>' +
+            '<span>Waiting for GitHub authorization…</span></div>' +
+          '<div class="adm-copilot-coderow">' +
+            '<span class="adm-copilot-code-label">Code</span>' +
+            '<code class="adm-copilot-code">' + esc(user_code) + '</code>' +
+            '<button type="button" class="admin-btn-sm adm-copilot-copy">Copy</button>' +
+          '</div>' +
+          '<a class="admin-btn-add adm-copilot-auth" href="' + encodeURI(authUrl) + '" target="_blank" rel="noopener">Authorize on GitHub ↗</a>' +
+          '<div class="adm-copilot-hint">A new tab opened on GitHub — approve there to finish. Didn\'t open? Use the button above.</div>' +
+        '</div>';
+      const copyBtn = status.querySelector('.adm-copilot-copy');
+      if (copyBtn) copyBtn.addEventListener('click', async () => {
+        try { await navigator.clipboard.writeText(user_code || ''); copyBtn.textContent = 'Copied'; setTimeout(() => { copyBtn.textContent = 'Copy'; }, 1500); } catch (e) {}
+      });
+      try { if (authUrl) window.open(authUrl, '_blank', 'noopener'); } catch (e) {}
+
+      const deadline = Date.now() + (expires_in || 900) * 1000;
+      const stepMs = Math.max((interval || 5), 2) * 1000;
+      const done = (cls, text) => { status.className = cls; status.textContent = text; reset(); };
+      const poll = async () => {
+        if (Date.now() > deadline) { done('admin-error', 'Authorization expired — try again.'); return; }
+        try {
+          const fd = new FormData(); fd.append('poll_id', poll_id);
+          const r = await fetch('/api/copilot/device/poll', { method: 'POST', body: fd, credentials: 'same-origin' });
+          const d = await r.json();
+          if (d.status === 'authorized') {
+            const n = ((d.endpoint && d.endpoint.models) || []).length;
+            done('admin-success', '✓ Connected — ' + n + ' Copilot model' + (n !== 1 ? 's' : '') + ' available.');
+            if (d.endpoint && d.endpoint.id) _recentlyAddedEpId = String(d.endpoint.id);
+            await loadEndpoints();
+            await _selectAddedModelInChat(d.endpoint || {});
+            return;
+          }
+          if (d.status === 'failed') { done('admin-error', 'Authorization failed (' + (d.error || 'denied') + ').'); return; }
+        } catch (e) { /* transient — keep polling */ }
+        setTimeout(poll, stepMs);
+      };
+      setTimeout(poll, stepMs);
+    });
+  }
+
   // Local "Add" button — sibling form for self-hosted base URLs.
   const localAddBtn = el('adm-epLocalAddBtn');
   const localTestBtn = el('adm-epLocalTestBtn');
diff --git a/static/js/slashCommands.js b/static/js/slashCommands.js
index 4d24972..97b3fb3 100644
--- a/static/js/slashCommands.js
+++ b/static/js/slashCommands.js
@@ -4735,11 +4735,47 @@ function _clearSetupCommandInput() {
   }
 }
 
+// GitHub Copilot device-flow sign-in, driven from chat (mirrors the Settings
+// "Connect GitHub Copilot" button). Replies via the setup guide messages.
+async function _setupCopilot() {
+  _clearSetupGuideMessages();
+  await _setupReply('Starting GitHub Copilot sign-in…');
+  let start;
+  try {
+    const r = await fetch(`${API_BASE}/api/copilot/device/start`, { method: 'POST', body: new FormData(), credentials: 'same-origin' });
+    start = await r.json();
+    if (!r.ok) { await _setupReply(start.detail || 'Failed to start Copilot sign-in.'); return; }
+  } catch (e) { await _setupReply('Request failed.'); return; }
+  const authUrl = start.verification_uri_complete || start.verification_uri || '';
+  await _setupReply(`Opening GitHub — approve the request (code ${start.user_code}). Waiting…`);
+  try { if (authUrl) window.open(authUrl, '_blank', 'noopener'); } catch (e) {}
+  const deadline = Date.now() + (start.expires_in || 900) * 1000;
+  const stepMs = Math.max((start.interval || 5), 2) * 1000;
+  const poll = async () => {
+    if (Date.now() > deadline) { await _setupReply('Copilot sign-in expired — run /setup copilot again.'); return; }
+    try {
+      const fd = new FormData(); fd.append('poll_id', start.poll_id);
+      const r = await fetch(`${API_BASE}/api/copilot/device/poll`, { method: 'POST', body: fd, credentials: 'same-origin' });
+      const d = await r.json();
+      if (d.status === 'authorized') {
+        const n = ((d.endpoint && d.endpoint.models) || []).length;
+        await _setupReply(`Connected — ${n} Copilot model${n !== 1 ? 's' : ''} available.`);
+        if (modelsModule) modelsModule.refreshModels(true);
+        return;
+      }
+      if (d.status === 'failed') { await _setupReply('Copilot sign-in failed (' + (d.error || 'denied') + ').'); return; }
+    } catch (e) { /* transient — keep polling */ }
+    setTimeout(poll, stepMs);
+  };
+  setTimeout(poll, stepMs);
+}
+
 async function _cmdSetup(args, ctx) {
   _hideWelcomeScreen();
   _clearSetupCommandInput();
   const topic = (args[0] || '').trim().toLowerCase();
   const topicArgs = args.slice(1);
+  if (topic === 'copilot' || topic === 'github') { await _setupCopilot(); return true; }
   const provider = _setupProviderFromInput(topic);
   if (provider) {
     _clearSetupGuideMessages();
@@ -5464,7 +5500,7 @@ const COMMANDS = {
     category: 'Getting started',
     help: 'Add local or API model endpoints',
     handler: _cmdSetup,
-    usage: '/setup local URL  ·  /setup groq KEY  ·  /setup endpoint'
+    usage: '/setup local URL  ·  /setup groq KEY  ·  /setup copilot  ·  /setup endpoint'
   },
   demo: {
     alias: ['tour'],
diff --git a/static/style.css b/static/style.css
index 69e02e7..ea99f3e 100644
--- a/static/style.css
+++ b/static/style.css
@@ -35782,3 +35782,66 @@ body.theme-frosted .modal {
      is already ≥16px and never zoomed — leave it so we don't shrink it. */
   .doc-email-richbody.doc-font-m { font-size: 16px !important; }
 }
+
+/* GitHub Copilot device-flow connect block (model endpoints → API) */
+.adm-copilot-connect {
+  margin-top: 10px;
+  padding-top: 10px;
+  border-top: 1px solid var(--border);
+  display: flex;
+  flex-wrap: wrap;
+  align-items: center;
+  gap: 8px;
+}
+.adm-copilot-connect #adm-copilotStatus { flex-basis: 100%; margin-top: 0; }
+.adm-copilot-panel {
+  display: flex;
+  flex-direction: column;
+  gap: 8px;
+  padding: 10px;
+  background: var(--bg);
+  border: 1px solid var(--border);
+  border-radius: 8px;
+}
+.adm-copilot-wait {
+  display: flex;
+  align-items: center;
+  gap: 6px;
+  font-size: 12px;
+  color: color-mix(in srgb, var(--fg) 70%, transparent);
+}
+.adm-copilot-coderow {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+}
+.adm-copilot-code-label {
+  font-size: 10px;
+  text-transform: uppercase;
+  letter-spacing: 0.06em;
+  color: color-mix(in srgb, var(--fg) 45%, transparent);
+}
+.adm-copilot-code {
+  font-family: var(--mono, ui-monospace, monospace);
+  font-size: 14px;
+  font-weight: 600;
+  letter-spacing: 0.12em;
+  padding: 4px 10px;
+  background: var(--panel);
+  border: 1px solid var(--border);
+  border-radius: 6px;
+  color: var(--fg);
+  user-select: all;
+}
+.adm-copilot-copy { margin-left: auto; }
+.adm-copilot-auth {
+  text-align: center;
+  text-decoration: none;
+  padding: 7px 12px;
+  font-size: 12px;
+}
+.adm-copilot-hint {
+  font-size: 11px;
+  line-height: 1.4;
+  color: color-mix(in srgb, var(--fg) 45%, transparent);
+}
diff --git a/tests/test_copilot.py b/tests/test_copilot.py
new file mode 100644
index 0000000..52d530a
--- /dev/null
+++ b/tests/test_copilot.py
@@ -0,0 +1,170 @@
+"""Tests for the GitHub Copilot provider integration (src/copilot.py + wiring)."""
+import types
+import pytest
+
+from src import copilot
+
+
+# ── Provider detection ─────────────────────────────────────────────────────
+
+@pytest.mark.parametrize("url,expected", [
+    ("https://api.githubcopilot.com", True),
+    ("https://api.githubcopilot.com/chat/completions", True),
+    ("https://copilot-api.acme.ghe.com", True),
+    ("https://sub.githubcopilot.com", True),
+    ("https://api.openai.com/v1", False),
+    ("https://githubcopilot.com.evil.test", False),  # lookalike host
+    ("", False),
+    (None, False),
+])
+def test_is_copilot_base(url, expected):
+    assert copilot.is_copilot_base(url) is expected
+
+
+def test_detect_provider_copilot():
+    from src.llm_core import _detect_provider
+    assert _detect_provider("https://api.githubcopilot.com") == "copilot"
+    assert _detect_provider("https://copilot-api.acme.ghe.com") == "copilot"
+    # lookalike must not be classified as copilot
+    assert _detect_provider("https://githubcopilot.com.evil.test") == "openai"
+
+
+def test_enterprise_base():
+    assert copilot.enterprise_base(None) == "https://api.githubcopilot.com"
+    assert copilot.enterprise_base("https://acme.ghe.com/") == "https://copilot-api.acme.ghe.com"
+    assert copilot.enterprise_base("acme.ghe.com") == "https://copilot-api.acme.ghe.com"
+
+
+# ── Headers ────────────────────────────────────────────────────────────────
+
+def test_copilot_headers_core():
+    h = copilot.copilot_headers("TOK")
+    assert h["Authorization"] == "Bearer TOK"
+    assert h["X-GitHub-Api-Version"] == copilot.COPILOT_API_VERSION
+    assert h["Openai-Intent"] == "conversation-edits"
+    assert h["Copilot-Integration-Id"]
+    assert h["x-initiator"] == "user"
+    assert "Copilot-Vision-Request" not in h
+
+
+def test_copilot_headers_agent_vision():
+    h = copilot.copilot_headers("TOK", agent=True, vision=True)
+    assert h["x-initiator"] == "agent"
+    assert h["Copilot-Vision-Request"] == "true"
+
+
+def test_copilot_headers_no_token():
+    h = copilot.copilot_headers(None)
+    assert "Authorization" not in h
+    assert h["X-GitHub-Api-Version"] == copilot.COPILOT_API_VERSION
+
+
+def test_build_headers_dispatches_to_copilot():
+    from src.endpoint_resolver import build_headers
+    h = build_headers("TOK", "https://api.githubcopilot.com")
+    assert h["Authorization"] == "Bearer TOK"
+    assert h["X-GitHub-Api-Version"] == copilot.COPILOT_API_VERSION
+    # OpenAI base must stay plain bearer (no copilot headers)
+    ho = build_headers("TOK", "https://api.openai.com/v1")
+    assert "X-GitHub-Api-Version" not in ho
+
+
+# ── Per-request flags ──────────────────────────────────────────────────────
+
+def test_request_flags_user():
+    assert copilot.request_flags([{"role": "user", "content": "hi"}]) == (False, False)
+
+
+def test_request_flags_agent_when_tool_last():
+    msgs = [{"role": "user", "content": "hi"}, {"role": "tool", "content": "x"}]
+    assert copilot.request_flags(msgs) == (True, False)
+
+
+def test_request_flags_vision():
+    msgs = [{"role": "user", "content": [
+        {"type": "text", "text": "look"},
+        {"type": "image_url", "image_url": {"url": "data:..."}},
+    ]}]
+    agent, vision = copilot.request_flags(msgs)
+    assert vision is True
+
+
+def test_apply_request_headers_mutates():
+    h = {"X-GitHub-Api-Version": "v"}
+    copilot.apply_request_headers(h, [{"role": "tool", "content": "x"}])
+    assert h["x-initiator"] == "agent"
+
+
+# ── Model discovery ────────────────────────────────────────────────────────
+
+def _fake_response(payload):
+    r = types.SimpleNamespace()
+    r.json = lambda: payload
+    r.raise_for_status = lambda: None
+    return r
+
+
+def test_fetch_models_filters_picker(monkeypatch):
+    payload = {"data": [
+        {"id": "gpt-4o", "model_picker_enabled": True,
+         "capabilities": {"supports": {"tool_calls": True, "vision": True}}},
+        {"id": "internal-embed", "model_picker_enabled": False,
+         "capabilities": {"supports": {"tool_calls": False}}},
+        {"id": "claude-3.5", "model_picker_enabled": True,
+         "capabilities": {"supports": {"tool_calls": True}}},
+    ]}
+    monkeypatch.setattr(copilot.httpx, "get", lambda *a, **k: _fake_response(payload))
+    models = copilot.fetch_models("https://api.githubcopilot.com", "TOK")
+    ids = {m["id"] for m in models}
+    assert ids == {"gpt-4o", "claude-3.5"}
+    gpt = next(m for m in models if m["id"] == "gpt-4o")
+    assert gpt["tool_calls"] is True and gpt["vision"] is True
+
+
+def test_fetch_models_fallback_when_no_picker(monkeypatch):
+    payload = {"data": [
+        {"id": "m1", "capabilities": {"supports": {}}},
+        {"id": "m2", "capabilities": {"supports": {}}},
+    ]}
+    monkeypatch.setattr(copilot.httpx, "get", lambda *a, **k: _fake_response(payload))
+    models = copilot.fetch_models("https://api.githubcopilot.com", "TOK")
+    assert {m["id"] for m in models} == {"m1", "m2"}
+
+
+# ── Device flow ────────────────────────────────────────────────────────────
+
+def test_request_device_code(monkeypatch):
+    captured = {}
+
+    def fake_post(url, headers=None, json=None, timeout=None):
+        captured["url"] = url
+        captured["json"] = json
+        return _fake_response({"device_code": "DC", "user_code": "ABCD-1234",
+                               "verification_uri": "https://github.com/login/device",
+                               "interval": 5, "expires_in": 900})
+
+    monkeypatch.setattr(copilot.httpx, "post", fake_post)
+    data = copilot.request_device_code()
+    assert data["device_code"] == "DC"
+    assert captured["url"] == "https://github.com/login/device/code"
+    assert captured["json"]["client_id"] == copilot.COPILOT_CLIENT_ID
+    assert captured["json"]["scope"] == "read:user"
+
+
+def test_poll_access_token(monkeypatch):
+    captured = {}
+
+    def fake_post(url, headers=None, json=None, timeout=None):
+        captured["json"] = json
+        return _fake_response({"access_token": "GHTOKEN"})
+
+    monkeypatch.setattr(copilot.httpx, "post", fake_post)
+    data = copilot.poll_access_token("github.com", "DC")
+    assert data["access_token"] == "GHTOKEN"
+    assert captured["json"]["grant_type"] == "urn:ietf:params:oauth:grant-type:device_code"
+    assert captured["json"]["device_code"] == "DC"
+
+
+def test_agent_loop_host_allowlisted():
+    from src.agent_loop import _API_HOSTS
+    assert "api.githubcopilot.com" in _API_HOSTS
diff --git a/tests/test_copilot_routes.py b/tests/test_copilot_routes.py
new file mode 100644
index 0000000..b75bb9f
--- /dev/null
+++ b/tests/test_copilot_routes.py
@@ -0,0 +1,80 @@
+"""DB-backed tests for Copilot endpoint provisioning (routes/copilot_routes.py)."""
+import json
+import pytest
+from sqlalchemy import create_engine
+from sqlalchemy.orm import sessionmaker
+
+from core.database import Base, ModelEndpoint
+import routes.copilot_routes as cr
+
+
+def _mem_db(monkeypatch):
+    engine = create_engine("sqlite:///:memory:")
+    Base.metadata.create_all(bind=engine)
+    TestSessionLocal = sessionmaker(bind=engine)
+    monkeypatch.setattr(cr, "SessionLocal", TestSessionLocal)
+    return TestSessionLocal
+
+
+def test_provision_creates_owner_scoped_endpoint(monkeypatch):
+    TestSessionLocal = _mem_db(monkeypatch)
+    monkeypatch.setattr(
+        cr.copilot, "fetch_models",
+        lambda base, token: [
+            {"id": "gpt-4o", "tool_calls": True, "vision": True},
+            {"id": "claude-3.5", "tool_calls": True, "vision": False},
+        ],
+    )
+
+    res = cr._provision_endpoint("GHTOK", "https://api.githubcopilot.com", "alice")
+
+    assert res["base_url"] == "https://api.githubcopilot.com"
+    assert res["models"] == ["gpt-4o", "claude-3.5"]
+
+    db = TestSessionLocal()
+    try:
+        ep = db.query(ModelEndpoint).filter(ModelEndpoint.id == res["id"]).first()
+        assert ep is not None
+        assert ep.owner == "alice"
+        assert ep.is_enabled is True
+        assert ep.supports_tools is True
+        assert ep.api_key == "GHTOK"  # round-trips through EncryptedText
+        assert json.loads(ep.cached_models) == ["gpt-4o", "claude-3.5"]
+    finally:
+        db.close()
+
+
+def test_provision_refreshes_existing_token(monkeypatch):
+    TestSessionLocal = _mem_db(monkeypatch)
+    monkeypatch.setattr(cr.copilot, "fetch_models", lambda base, token: [{"id": "gpt-4o", "tool_calls": True}])
+
+    first = cr._provision_endpoint("OLD", "https://api.githubcopilot.com", "bob")
+    second = cr._provision_endpoint("NEW", "https://api.githubcopilot.com", "bob")
+
+    # Same row reused (no duplicate), token refreshed.
+    assert first["id"] == second["id"]
+    db = TestSessionLocal()
+    try:
+        rows = db.query(ModelEndpoint).filter(ModelEndpoint.owner == "bob").all()
+        assert len(rows) == 1
+        assert rows[0].api_key == "NEW"
+    finally:
+        db.close()
+
+
+def test_provision_handles_model_fetch_failure(monkeypatch):
+    TestSessionLocal = _mem_db(monkeypatch)
+
+    def boom(base, token):
+        raise RuntimeError("network down")
+
+    monkeypatch.setattr(cr.copilot, "fetch_models", boom)
+    # Should still create the endpoint (login succeeded) with an empty model list.
+    res = cr._provision_endpoint("GHTOK", "https://api.githubcopilot.com", "carol")
+    assert res["models"] == []
+    db = TestSessionLocal()
+    try:
+        ep = db.query(ModelEndpoint).filter(ModelEndpoint.id == res["id"]).first()
+        assert ep is not None and ep.api_key == "GHTOK"
+    finally:
+        db.close()