diff --git a/litellm/integrations/websearch_interception/handler.py b/litellm/integrations/websearch_interception/handler.py
index bfae6d5b7b0f..60100e8c2fdd 100644
--- a/litellm/integrations/websearch_interception/handler.py
+++ b/litellm/integrations/websearch_interception/handler.py
@@ -120,21 +120,26 @@ async def try_short_circuit_search(
         if self.enabled_providers is not None and provider_str not in self.enabled_providers:
             return None
 
-        # Only short-circuit for providers without native Anthropic Messages
-        # support.  Providers that have a BaseAnthropicMessagesConfig (bedrock,
-        # vertex_ai, azure_ai, anthropic) already use the agentic loop, which
-        # includes a follow-up LLM call to synthesize the answer from search
-        # results.  Short-circuiting those would skip that synthesis step and
-        # return raw search text — a regression for existing users.
+        # Only short-circuit for providers whose Anthropic Messages agentic loop
+        # does not run web_search itself. Providers that have a
+        # BaseAnthropicMessagesConfig which handles web search natively (bedrock,
+        # vertex_ai, azure_ai, anthropic) already perform the search plus a
+        # follow-up LLM synthesis step; short-circuiting those would skip that
+        # synthesis and return raw search text — a regression for existing users.
+        #
+        # github_copilot has a BaseAnthropicMessagesConfig (added for thinking
+        # passthrough) but does not handle web_search natively, so its config
+        # returns handles_web_search_natively() == False and we still short-circuit
+        # web-search-only requests against it.
         try:
             provider_enum = LlmProviders(provider_str)
             anthropic_config = ProviderConfigManager.get_provider_anthropic_messages_config(
                 model=model, provider=provider_enum
             )
-            if anthropic_config is not None:
+            if anthropic_config is not None and anthropic_config.handles_web_search_natively():
                 verbose_logger.debug(
                     f"WebSearchInterception: Skipping short-circuit for {provider_str} "
-                    "(provider has native Anthropic Messages support, using agentic loop)"
+                    "(provider handles web search natively via the agentic loop)"
                 )
                 return None
         except (ValueError, Exception):
diff --git a/litellm/llms/base_llm/anthropic_messages/transformation.py b/litellm/llms/base_llm/anthropic_messages/transformation.py
index 966995bc571f..448c1d070096 100644
--- a/litellm/llms/base_llm/anthropic_messages/transformation.py
+++ b/litellm/llms/base_llm/anthropic_messages/transformation.py
@@ -114,6 +114,19 @@ def should_filter_anthropic_beta_headers(self) -> bool:
         """
         return True
 
+    def handles_web_search_natively(self) -> bool:
+        """
+        Whether the upstream this config routes to executes ``web_search`` tools
+        itself as part of its Anthropic Messages agentic loop.
+
+        The web-search interception handler short-circuits web-search-only
+        requests (running the search itself and returning synthetic results) only
+        for providers that do NOT. Providers whose agentic loop already performs
+        the search plus a follow-up synthesis step (bedrock, vertex_ai, ...)
+        return True so those requests flow through untouched.
+        """
+        return True
+
     def get_async_streaming_response_iterator(
         self,
         model: str,
diff --git a/litellm/llms/github_copilot/messages/__init__.py b/litellm/llms/github_copilot/messages/__init__.py
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/litellm/llms/github_copilot/messages/transformation.py b/litellm/llms/github_copilot/messages/transformation.py
new file mode 100644
index 000000000000..fb3f0a4e1596
--- /dev/null
+++ b/litellm/llms/github_copilot/messages/transformation.py
@@ -0,0 +1,118 @@
+from typing import Any, Optional
+
+from litellm.exceptions import AuthenticationError
+from litellm.llms.anthropic.experimental_pass_through.messages.transformation import (
+    AnthropicMessagesConfig,
+)
+
+from ..authenticator import Authenticator
+from ..common_utils import (
+    DEFAULT_GITHUB_COPILOT_API_BASE,
+    GetAPIKeyError,
+    get_copilot_default_headers,
+)
+
+_MESSAGES_PROXY_API_VERSION = "2026-06-01"
+
+
+class GithubCopilotAnthropicMessagesConfig(AnthropicMessagesConfig):
+    """
+    GitHub Copilot implementation of Anthropic messages API.
+    Routes requests to Copilot's /v1/messages endpoint with appropriate authentication and headers.
+    """
+
+    def __init__(self) -> None:
+        super().__init__()
+        self.authenticator = Authenticator()
+
+    def handles_web_search_natively(self) -> bool:
+        """
+        Copilot's /v1/messages endpoint does not execute ``web_search`` tools, so
+        the interception handler must short-circuit web-search-only requests
+        instead of routing them here.
+        """
+        return False
+
+    def should_filter_anthropic_beta_headers(self) -> bool:
+        """
+        Copilot's /v1/messages is a native Anthropic Messages passthrough, so
+        ``anthropic-beta`` values injected by ``_update_headers_with_anthropic_beta``
+        (context_management, structured outputs, ...) must reach the upstream
+        verbatim. The default provider-scoped filter would drop them because
+        github_copilot has no entry in ``anthropic_beta_headers_config.json``.
+        """
+        return False
+
+    def validate_anthropic_messages_environment(
+        self,
+        headers: dict,
+        model: str,
+        messages: list[Any],
+        optional_params: dict,
+        litellm_params: dict,
+        api_key: Optional[str] = None,
+        api_base: Optional[str] = None,
+    ) -> tuple[dict, Optional[str]]:
+        """
+        Validate environment for GitHub Copilot and add Copilot-specific headers.
+
+        The caller-supplied ``api_base`` is intentionally ignored. Routing this
+        request anywhere other than the authenticated Copilot endpoint would
+        leak the Copilot bearer token to a caller-controlled URL.
+        """
+        # Always use the Copilot endpoint resolved from the authenticated
+        # session, never the caller-supplied api_base. rstrip so a
+        # tenant-specific base with a trailing slash does not yield a
+        # double-slash URL once "/v1/messages" is appended downstream.
+        dynamic_api_base = (self.authenticator.get_api_base() or DEFAULT_GITHUB_COPILOT_API_BASE).rstrip("/")
+        try:
+            dynamic_api_key = self.authenticator.get_api_key()
+        except GetAPIKeyError as e:
+            raise AuthenticationError(
+                model=model,
+                llm_provider="github_copilot",
+                message=str(e),
+            )
+
+        # Merge Copilot headers with provided headers
+        copilot_headers = get_copilot_default_headers(dynamic_api_key)
+        for key, value in copilot_headers.items():
+            if key not in headers:
+                headers[key] = value
+
+        headers["openai-intent"] = "messages-proxy"
+        headers["x-interaction-type"] = "messages-proxy"
+        headers["x-github-api-version"] = _MESSAGES_PROXY_API_VERSION
+
+        if "anthropic-version" not in headers:
+            headers["anthropic-version"] = "2023-06-01"
+
+        headers = self._update_headers_with_anthropic_beta(
+            headers, optional_params, custom_llm_provider="github_copilot"
+        )
+
+        return headers, dynamic_api_base
+
+    def get_complete_url(
+        self,
+        api_base: Optional[str],
+        api_key: Optional[str],
+        model: str,
+        optional_params: dict,
+        litellm_params: dict,
+        stream: Optional[bool] = None,
+    ) -> str:
+        """
+        Return the complete URL for GitHub Copilot /v1/messages endpoint.
+
+        ``api_base`` here is the value already resolved by
+        ``validate_anthropic_messages_environment`` (the authenticated Copilot
+        host), not the raw caller-supplied base — that one is discarded there to
+        avoid leaking the Copilot bearer token to a caller-controlled URL. We
+        reuse it to avoid a second authenticator read, falling back to a fresh
+        resolution only if it was not provided.
+        """
+        resolved = (api_base or self.authenticator.get_api_base() or DEFAULT_GITHUB_COPILOT_API_BASE).rstrip("/")
+        if not resolved.endswith("/v1/messages"):
+            resolved = f"{resolved}/v1/messages"
+        return resolved
diff --git a/litellm/model_prices_and_context_window_backup.json b/litellm/model_prices_and_context_window_backup.json
index b16e1015255e..c9dae4d9a473 100644
--- a/litellm/model_prices_and_context_window_backup.json
+++ b/litellm/model_prices_and_context_window_backup.json
@@ -19176,7 +19176,8 @@
         "max_tokens": 16000,
         "mode": "chat",
         "supported_endpoints": [
-            "/v1/chat/completions"
+            "/v1/chat/completions",
+            "/v1/messages"
         ],
         "supports_function_calling": true,
         "supports_parallel_function_calling": true,
@@ -19189,7 +19190,8 @@
         "max_tokens": 16000,
         "mode": "chat",
         "supported_endpoints": [
-            "/v1/chat/completions"
+            "/v1/chat/completions",
+            "/v1/messages"
         ],
         "supports_function_calling": true,
         "supports_parallel_function_calling": true,
@@ -19242,7 +19244,8 @@
         "max_tokens": 16000,
         "mode": "chat",
         "supported_endpoints": [
-            "/v1/chat/completions"
+            "/v1/chat/completions",
+            "/v1/messages"
         ],
         "supports_function_calling": true,
         "supports_parallel_function_calling": true,
diff --git a/litellm/utils.py b/litellm/utils.py
index 45ce5332f1d0..26d3ae32739a 100644
--- a/litellm/utils.py
+++ b/litellm/utils.py
@@ -7984,6 +7984,13 @@ def _get_provider_anthropic_messages_config_cached(
             )
 
             return DeepSeekAnthropicMessagesConfig()
+        elif litellm.LlmProviders.GITHUB_COPILOT == provider:
+            if "claude" in model_lower:
+                from litellm.llms.github_copilot.messages.transformation import (
+                    GithubCopilotAnthropicMessagesConfig,
+                )
+
+                return GithubCopilotAnthropicMessagesConfig()
         return None
 
     @staticmethod
diff --git a/tests/test_litellm/llms/github_copilot/messages/__init__.py b/tests/test_litellm/llms/github_copilot/messages/__init__.py
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/tests/test_litellm/llms/github_copilot/messages/test_github_copilot_messages_transformation.py b/tests/test_litellm/llms/github_copilot/messages/test_github_copilot_messages_transformation.py
new file mode 100644
index 000000000000..01787c07d272
--- /dev/null
+++ b/tests/test_litellm/llms/github_copilot/messages/test_github_copilot_messages_transformation.py
@@ -0,0 +1,328 @@
+import os
+import sys
+from unittest.mock import MagicMock
+
+import pytest
+
+sys.path.insert(0, os.path.abspath("../.."))
+
+from litellm.exceptions import AuthenticationError
+from litellm.llms.github_copilot.common_utils import GetAPIKeyError
+from litellm.llms.github_copilot.messages.transformation import (
+    GithubCopilotAnthropicMessagesConfig,
+)
+
+
+def test_github_copilot_anthropic_messages_config_init():
+    """Test GithubCopilotAnthropicMessagesConfig initialization."""
+    config = GithubCopilotAnthropicMessagesConfig()
+    assert config is not None
+    assert hasattr(config, "authenticator")
+
+
+def test_github_copilot_anthropic_messages_get_complete_url():
+    """get_complete_url builds the /v1/messages URL from the base it is handed.
+
+    In the request flow that ``api_base`` is the value already resolved by
+    validate_anthropic_messages_environment (the authenticated Copilot host); the
+    caller-supplied base is discarded there, not here (see the validate tests).
+    """
+    config = GithubCopilotAnthropicMessagesConfig()
+    config.authenticator = MagicMock()
+    config.authenticator.get_api_base.return_value = None
+
+    # No api_base supplied and no authenticator base -> default Copilot endpoint.
+    url = config.get_complete_url(
+        api_base=None,
+        api_key=None,
+        model="github_copilot/claude-haiku-4.5",
+        optional_params={},
+        litellm_params={},
+    )
+    assert url == "https://api.githubcopilot.com/v1/messages"
+    # Falls back to a single authenticator read, not a hard-coded second one.
+    config.authenticator.get_api_base.assert_called()
+
+    # The resolved (validated) base passed in is reused verbatim; no extra read.
+    config.authenticator.get_api_base.reset_mock()
+    url = config.get_complete_url(
+        api_base="https://api.business.githubcopilot.com",
+        api_key=None,
+        model="github_copilot/claude-haiku-4.5",
+        optional_params={},
+        litellm_params={},
+    )
+    assert url == "https://api.business.githubcopilot.com/v1/messages"
+    config.authenticator.get_api_base.assert_not_called()
+
+    # A trailing slash on the base must not produce a double-slash URL.
+    url = config.get_complete_url(
+        api_base="https://api.business.githubcopilot.com/",
+        api_key=None,
+        model="github_copilot/claude-haiku-4.5",
+        optional_params={},
+        litellm_params={},
+    )
+    assert url == "https://api.business.githubcopilot.com/v1/messages"
+
+    # An already-complete /v1/messages base is left untouched.
+    url = config.get_complete_url(
+        api_base="https://api.githubcopilot.com/v1/messages",
+        api_key=None,
+        model="github_copilot/claude-haiku-4.5",
+        optional_params={},
+        litellm_params={},
+    )
+    assert url == "https://api.githubcopilot.com/v1/messages"
+
+
+def test_github_copilot_anthropic_messages_get_complete_url_normalizes_authenticator_trailing_slash():
+    """A tenant base with a trailing slash from the authenticator fallback must
+    not yield a double-slash URL."""
+    config = GithubCopilotAnthropicMessagesConfig()
+    config.authenticator = MagicMock()
+    config.authenticator.get_api_base.return_value = "https://api.business.githubcopilot.com/"
+
+    url = config.get_complete_url(
+        api_base=None,
+        api_key=None,
+        model="github_copilot/claude-haiku-4.5",
+        optional_params={},
+        litellm_params={},
+    )
+    assert url == "https://api.business.githubcopilot.com/v1/messages"
+
+
+def test_github_copilot_anthropic_messages_validate_environment():
+    """Test environment validation and header injection."""
+    config = GithubCopilotAnthropicMessagesConfig()
+
+    # Mock the authenticator
+    config.authenticator = MagicMock()
+    config.authenticator.get_api_key.return_value = "gh.test-key-123"
+    config.authenticator.get_api_base.return_value = None
+
+    headers = {}
+    # Pass a hostile api_base to confirm it is ignored.
+    validated_headers, api_base = config.validate_anthropic_messages_environment(
+        headers=headers,
+        model="github_copilot/claude-haiku-4.5",
+        messages=[{"role": "user", "content": "Hello"}],
+        optional_params={},
+        litellm_params={},
+        api_key=None,
+        api_base="https://attacker.example.com",
+    )
+
+    assert "copilot-integration-id" in validated_headers
+    assert validated_headers["copilot-integration-id"] == "vscode-chat"
+    assert "Authorization" in validated_headers
+    assert "anthropic-version" in validated_headers
+    assert validated_headers["anthropic-version"] == "2023-06-01"
+    # /v1/messages must use the messages-proxy intent so the Copilot backend
+    # enables Anthropic-native features (context_management, thinking, etc.).
+    assert validated_headers["openai-intent"] == "messages-proxy"
+    assert validated_headers["x-interaction-type"] == "messages-proxy"
+    assert validated_headers["x-github-api-version"] == "2026-06-01"
+    assert api_base == "https://api.githubcopilot.com"
+
+
+def test_github_copilot_anthropic_messages_validate_environment_injects_beta_headers():
+    """Anthropic-beta headers must be auto-injected for advanced features
+    (context_management, output_format, etc.) — matches the parent
+    AnthropicMessagesConfig contract."""
+    config = GithubCopilotAnthropicMessagesConfig()
+    config.authenticator = MagicMock()
+    config.authenticator.get_api_key.return_value = "gh.test-key"
+    config.authenticator.get_api_base.return_value = None
+
+    validated_headers, _ = config.validate_anthropic_messages_environment(
+        headers={},
+        model="github_copilot/claude-haiku-4.5",
+        messages=[{"role": "user", "content": "Hello"}],
+        optional_params={"output_format": {"type": "json_object"}},
+        litellm_params={},
+        api_key=None,
+        api_base=None,
+    )
+
+    assert "anthropic-beta" in validated_headers
+    assert "structured-outputs-2025-11-13" in validated_headers["anthropic-beta"]
+
+
+def test_github_copilot_anthropic_messages_validate_environment_preserves_caller_anthropic_version():
+    """Caller-supplied anthropic-version must be forwarded verbatim."""
+    config = GithubCopilotAnthropicMessagesConfig()
+    config.authenticator = MagicMock()
+    config.authenticator.get_api_key.return_value = "gh.test-key"
+    config.authenticator.get_api_base.return_value = None
+
+    validated_headers, _ = config.validate_anthropic_messages_environment(
+        headers={"anthropic-version": "2024-10-22"},
+        model="github_copilot/claude-haiku-4.5",
+        messages=[{"role": "user", "content": "Hello"}],
+        optional_params={},
+        litellm_params={},
+        api_key=None,
+        api_base=None,
+    )
+
+    assert validated_headers["anthropic-version"] == "2024-10-22"
+
+
+def test_github_copilot_anthropic_messages_validate_environment_injects_context_management_beta():
+    """context_management in optional_params must trigger the corresponding
+    anthropic-beta header so the Copilot backend accepts the field."""
+    config = GithubCopilotAnthropicMessagesConfig()
+    config.authenticator = MagicMock()
+    config.authenticator.get_api_key.return_value = "gh.test-key"
+    config.authenticator.get_api_base.return_value = None
+
+    validated_headers, _ = config.validate_anthropic_messages_environment(
+        headers={},
+        model="github_copilot/claude-haiku-4.5",
+        messages=[{"role": "user", "content": "Hello"}],
+        optional_params={"context_management": {"edits": [{"type": "clear_tool_uses_20250919"}]}},
+        litellm_params={},
+        api_key=None,
+        api_base=None,
+    )
+
+    assert validated_headers["openai-intent"] == "messages-proxy"
+    assert validated_headers["x-interaction-type"] == "messages-proxy"
+    assert "anthropic-beta" in validated_headers
+    assert "context-management-2025-06-27" in validated_headers["anthropic-beta"]
+
+
+def test_github_copilot_anthropic_messages_validate_environment_auth_error():
+    """Test error handling when authentication fails."""
+    config = GithubCopilotAnthropicMessagesConfig()
+
+    # Mock the authenticator to raise an error
+    config.authenticator = MagicMock()
+    config.authenticator.get_api_key.side_effect = GetAPIKeyError(status_code=401, message="No valid API key found")
+
+    with pytest.raises(AuthenticationError):
+        config.validate_anthropic_messages_environment(
+            headers={},
+            model="github_copilot/claude-haiku-4.5",
+            messages=[{"role": "user", "content": "Hello"}],
+            optional_params={},
+            litellm_params={},
+            api_key=None,
+            api_base=None,
+        )
+
+
+def test_github_copilot_anthropic_messages_supported_params():
+    """Test supported parameters list."""
+    config = GithubCopilotAnthropicMessagesConfig()
+    params = config.get_supported_anthropic_messages_params("github_copilot/claude-haiku-4.5")
+
+    # Should inherit from AnthropicMessagesConfig
+    assert "messages" in params
+    assert "model" in params
+    assert "max_tokens" in params
+    assert "thinking" in params
+
+
+def test_provider_config_manager_dispatches_claude_to_copilot_messages_config():
+    """ProviderConfigManager must return the Copilot Anthropic Messages config
+    for Claude models served via github_copilot."""
+    from litellm.types.utils import LlmProviders
+    from litellm.utils import ProviderConfigManager
+
+    config = ProviderConfigManager.get_provider_anthropic_messages_config(
+        model="github_copilot/claude-haiku-4.5",
+        provider=LlmProviders.GITHUB_COPILOT,
+    )
+
+    assert isinstance(config, GithubCopilotAnthropicMessagesConfig)
+
+
+def test_provider_config_manager_skips_non_claude_copilot_models():
+    """Non-Claude github_copilot models (e.g. gpt-*) must not be routed through
+    the Anthropic Messages dispatch."""
+    from litellm.types.utils import LlmProviders
+    from litellm.utils import ProviderConfigManager
+
+    config = ProviderConfigManager.get_provider_anthropic_messages_config(
+        model="github_copilot/gpt-5-mini",
+        provider=LlmProviders.GITHUB_COPILOT,
+    )
+
+    assert config is None
+
+
+def test_github_copilot_anthropic_messages_validate_environment_normalizes_trailing_slash():
+    """A tenant base with a trailing slash from the authenticator must be
+    normalized so the URL built downstream has no double slash."""
+    config = GithubCopilotAnthropicMessagesConfig()
+    config.authenticator = MagicMock()
+    config.authenticator.get_api_key.return_value = "gh.test-key"
+    config.authenticator.get_api_base.return_value = "https://api.business.githubcopilot.com/"
+
+    _, api_base = config.validate_anthropic_messages_environment(
+        headers={},
+        model="github_copilot/claude-haiku-4.5",
+        messages=[{"role": "user", "content": "Hello"}],
+        optional_params={},
+        litellm_params={},
+        api_key=None,
+        api_base="https://attacker.example.com",
+    )
+
+    assert api_base == "https://api.business.githubcopilot.com"
+
+
+def test_github_copilot_config_disables_anthropic_beta_filtering():
+    """Copilot's /v1/messages is a native Anthropic passthrough, so injected
+    anthropic-beta values (context_management, structured outputs, ...) must be
+    forwarded verbatim. The default provider-scoped filter would drop them
+    because github_copilot has no entry in the beta headers config; a regression
+    here would silently disable header-gated Anthropic features for Copilot."""
+    from litellm.anthropic_beta_headers_manager import update_headers_with_filtered_beta
+    from litellm.llms.anthropic.experimental_pass_through.messages.transformation import (
+        AnthropicMessagesConfig,
+    )
+
+    config = GithubCopilotAnthropicMessagesConfig()
+    assert config.should_filter_anthropic_beta_headers() is False
+    assert AnthropicMessagesConfig().should_filter_anthropic_beta_headers() is True
+
+    config.authenticator = MagicMock()
+    config.authenticator.get_api_key.return_value = "gh.test-key"
+    config.authenticator.get_api_base.return_value = None
+
+    headers, _ = config.validate_anthropic_messages_environment(
+        headers={},
+        model="github_copilot/claude-haiku-4.5",
+        messages=[{"role": "user", "content": "Hello"}],
+        optional_params={"context_management": {"edits": [{"type": "clear_tool_uses_20250919"}]}},
+        litellm_params={},
+        api_key=None,
+        api_base=None,
+    )
+
+    assert "context-management-2025-06-27" in headers["anthropic-beta"]
+
+    # The override is load-bearing: had the config opted into the provider-scoped
+    # filter, the handler would have run it and dropped every value, since
+    # github_copilot has no mapping. Prove that here so a regression that flips
+    # should_filter back on is caught as the silent feature breakage it causes.
+    stripped = update_headers_with_filtered_beta(headers=dict(headers), provider="github_copilot")
+    assert "anthropic-beta" not in stripped
+
+
+def test_github_copilot_config_does_not_handle_web_search_natively():
+    """Copilot's /v1/messages does not run web_search, so its config must report
+    handles_web_search_natively() == False. This is what keeps the web-search
+    interception handler short-circuiting Copilot instead of routing to it, even
+    though Copilot now has a BaseAnthropicMessagesConfig. The base Anthropic
+    config (bedrock/vertex/anthropic path) must report True."""
+    from litellm.llms.anthropic.experimental_pass_through.messages.transformation import (
+        AnthropicMessagesConfig,
+    )
+
+    assert GithubCopilotAnthropicMessagesConfig().handles_web_search_natively() is False
+    assert AnthropicMessagesConfig().handles_web_search_natively() is True