diff --git a/src/ucode/agents/copilot.py b/src/ucode/agents/copilot.py
index 19a52b8e..7c6a6e65 100644
--- a/src/ucode/agents/copilot.py
+++ b/src/ucode/agents/copilot.py
@@ -6,15 +6,35 @@
 to clean up; the values are also injected directly into the child process's
 environment at launch.
 
-We point Copilot CLI's `openai` provider at the Databricks MLflow chat-completions
-gateway, which serves Claude and codex (gpt-5) models. Gemini is intentionally
-excluded — Databricks' Gemini translation layer rejects the `stream_options`
-field that Copilot CLI sends, so Gemini models 400 on every request.
+Copilot CLI supports two BYOK provider dialects. Claude models get its native
+`anthropic` provider type, pointed at the same Messages-API gateway path
+claude.py uses — Copilot's own runtime inserts `cache_control` breakpoints on
+that path, so the (typically huge, shared) system/tool prefix actually caches.
+Codex (gpt-5) has no native-dialect provider on Copilot's side, so it stays on
+the `openai` provider against the Databricks MLflow chat-completions gateway.
+Gemini is intentionally excluded from both — Databricks' Gemini translation
+layer rejects the `stream_options` field that Copilot CLI sends, so Gemini
+models 400 on every request.
+
+The `anthropic` path needs two things not obvious from `copilot help
+providers`, both confirmed live: Bearer auth, not the `x-api-key` that
+provider type sends by default (Databricks' gateway 401s on it); and a
+well-known model id kept separate from the actual wire id, or Copilot sends
+`temperature`, which current-gen Claude models reject. See render_env_overlay.
+
+That last part only works from Copilot 1.0.81-6 onward — verified live across
+1.0.79 through 1.0.83. Below it, Copilot always sends `temperature` on the
+`anthropic` path regardless of the model id, so Sonnet 5/Opus 5 (which reject
+it outright) 400 on every request; Haiku 4.5 tolerates `temperature` and
+would work either way, but the version gate below applies to every Claude
+model for simplicity. Below 1.0.81-6, Claude models keep the old `openai`
+path — uncached, but that's the status quo, not a regression.
 """
 
 from __future__ import annotations
 
 import os
+import re
 import signal
 import subprocess
 import threading
@@ -32,10 +52,11 @@
 )
 from ucode.databricks import (
     TOKEN_REFRESH_INTERVAL_SECONDS,
-    build_copilot_base_url,
+    build_copilot_base_urls,
     get_databricks_token,
 )
 from ucode.state import mark_tool_managed, save_state
+from ucode.telemetry import agent_version
 
 COPILOT_CONFIG_DIR = Path.home() / ".copilot"
 COPILOT_ENV_PATH = COPILOT_CONFIG_DIR / "ucode.env"
@@ -55,6 +76,8 @@
     "COPILOT_PROVIDER_TYPE",
     "COPILOT_PROVIDER_BASE_URL",
     "COPILOT_MODEL",
+    "COPILOT_PROVIDER_MODEL_ID",
+    "COPILOT_PROVIDER_WIRE_MODEL",
     "COPILOT_PROVIDER_BEARER_TOKEN",
     "COPILOT_OFFLINE",
     "OAUTH_TOKEN",
@@ -64,6 +87,28 @@
     "OPENAI_API_KEY",
     "COPILOT_PROVIDER_API_KEY",
 ]
+# COPILOT_MODEL (openai) vs COPILOT_PROVIDER_MODEL_ID+COPILOT_PROVIDER_WIRE_MODEL
+# (anthropic) are mutually exclusive — cleared before every write so switching
+# families doesn't leave the other set stale in ~/.copilot/ucode.env.
+_MODEL_SELECTION_KEYS = (
+    "COPILOT_MODEL",
+    "COPILOT_PROVIDER_MODEL_ID",
+    "COPILOT_PROVIDER_WIRE_MODEL",
+)
+
+_CANONICAL_CLAUDE_MODEL_ID_RE = re.compile(r"claude-[a-z0-9]+(?:-[a-z0-9]+)*", re.IGNORECASE)
+# Same Bedrock version-marker pattern usage.py's normalize_price_key strips,
+# e.g. "claude-opus-4-8-v1:0" -> "claude-opus-4-8" — Copilot's catalog doesn't
+# carry the AWS version suffix, so leaving it in re-triggers the "unrecognized
+# model" fallback (including the `temperature` send) this split is for.
+_BEDROCK_VERSION_SUFFIX_RE = re.compile(r"-v\d+(:\d+)?$")
+
+# (major, minor, patch, prerelease) — see the module docstring. A version with
+# no prerelease suffix (a final release) is a 4th component of _UNRELEASED so
+# it always sorts after every prerelease of the same (major, minor, patch).
+MINIMUM_COPILOT_ANTHROPIC_VERSION = (1, 0, 81, 6)
+_UNRELEASED = 999_999
+_COPILOT_VERSION_RE = re.compile(r"(\d+)\.(\d+)\.(\d+)(?:-(\d+))?")
 
 
 def is_update_available() -> tuple[str, str] | None:
@@ -91,10 +136,54 @@ def default_model(state: dict) -> str | None:
     return None
 
 
+def _is_claude_model(model: str) -> bool:
+    # Every Claude family/model id ucode discovers or pins contains "claude"
+    # (canonical Anthropic names like "claude-sonnet-5", or Bedrock-style
+    # slugs like "us.anthropic.claude-opus-4-8") — same substring check
+    # `databricks.py` already uses elsewhere to special-case the family.
+    return "claude" in model.lower()
+
+
+def _canonical_claude_model_id(model: str) -> str:
+    # e.g. "system.ai.claude-sonnet-5" -> "claude-sonnet-5" — the well-known
+    # name Copilot needs to recognize the model (see render_env_overlay).
+    # Lowercased and stripped of any Bedrock version suffix so it matches
+    # Copilot's catalog regardless of the input's casing or source.
+    match = _CANONICAL_CLAUDE_MODEL_ID_RE.search(model)
+    canonical = match.group(0).lower() if match else model.lower()
+    return _BEDROCK_VERSION_SUFFIX_RE.sub("", canonical)
+
+
+def _parse_copilot_version(value: str) -> tuple[int, int, int, int] | None:
+    match = _COPILOT_VERSION_RE.search(value)
+    if not match:
+        return None
+    major, minor, patch, pre = match.groups()
+    return int(major), int(minor), int(patch), int(pre) if pre is not None else _UNRELEASED
+
+
+def _supports_anthropic_provider() -> bool:
+    version = _parse_copilot_version(agent_version(SPEC["binary"]))
+    return version is not None and version >= MINIMUM_COPILOT_ANTHROPIC_VERSION
+
+
 def render_env_overlay(workspace: str, model: str, token: str) -> dict[str, str]:
+    base_urls = build_copilot_base_urls(workspace)
+    if _is_claude_model(model) and _supports_anthropic_provider():
+        return {
+            "COPILOT_PROVIDER_TYPE": "anthropic",
+            "COPILOT_PROVIDER_BASE_URL": base_urls["anthropic"],
+            # Not COPILOT_MODEL: that would default both ids below to the
+            # unrecognized catalog id and Copilot would send `temperature`.
+            "COPILOT_PROVIDER_MODEL_ID": _canonical_claude_model_id(model),
+            "COPILOT_PROVIDER_WIRE_MODEL": model,
+            "COPILOT_PROVIDER_BEARER_TOKEN": token,  # not API_KEY — see module docstring
+            "COPILOT_OFFLINE": "true",
+            "OAUTH_TOKEN": token,
+        }
     return {
         "COPILOT_PROVIDER_TYPE": "openai",
-        "COPILOT_PROVIDER_BASE_URL": build_copilot_base_url(workspace),
+        "COPILOT_PROVIDER_BASE_URL": base_urls["openai"],
         "COPILOT_MODEL": model,
         "COPILOT_PROVIDER_BEARER_TOKEN": token,
         "COPILOT_OFFLINE": "true",
@@ -161,6 +250,8 @@ def write_tool_config(
     existing = parse_dotenv(COPILOT_ENV_PATH)
     for key in LEGACY_ENV_KEYS:
         existing.pop(key, None)
+    for key in _MODEL_SELECTION_KEYS:
+        existing.pop(key, None)
     existing.update(overlay)
     write_dotenv(COPILOT_ENV_PATH, existing)
     state = mark_tool_managed(state, "copilot", MANAGED_KEYS)
diff --git a/src/ucode/databricks.py b/src/ucode/databricks.py
index e98faf95..d736e65f 100644
--- a/src/ucode/databricks.py
+++ b/src/ucode/databricks.py
@@ -3206,12 +3206,23 @@ def build_pi_base_urls(workspace: str) -> dict[str, str]:
     }
 
 
-def build_copilot_base_url(workspace: str) -> str:
-    # Copilot CLI's `openai` provider appends `/chat/completions` to the
-    # configured base URL. The Databricks MLflow chat-completions gateway is
-    # OpenAI-compatible and serves Claude, codex (gpt-5), and gemini models
-    # behind one URL.
-    return f"{workspace}/ai-gateway/mlflow/v1"
+def build_copilot_base_urls(workspace: str) -> dict[str, str]:
+    # Copilot CLI's `anthropic` provider type speaks the native Anthropic
+    # Messages API directly, against the same gateway path claude.py uses.
+    # That's what lets Copilot's own cache_control-insertion logic run and
+    # cache the (typically huge, shared) system/tool prefix — the `openai`
+    # provider's wire format has no field to carry a cache breakpoint, so a
+    # Claude model proxied that way never gets a cache hit.
+    #
+    # Codex (gpt-5) has no native-dialect provider type on Copilot's side, so
+    # it stays on `openai` against the OpenAI-compatible MLflow
+    # chat-completions gateway, which serves Claude, codex, and gemini behind
+    # one URL. Copilot CLI's `openai` provider appends `/chat/completions` to
+    # this base URL.
+    return {
+        "anthropic": build_tool_base_url("claude", workspace),
+        "openai": f"{workspace}/ai-gateway/mlflow/v1",
+    }
 
 
 def build_shared_base_urls(workspace: str) -> dict[str, str | dict[str, str]]:
@@ -3220,7 +3231,7 @@ def build_shared_base_urls(workspace: str) -> dict[str, str | dict[str, str]]:
         "claude": build_tool_base_url("claude", workspace),
         "gemini": build_tool_base_url("gemini", workspace),
         "opencode": build_opencode_base_urls(workspace),
-        "copilot": build_copilot_base_url(workspace),
+        "copilot": build_copilot_base_urls(workspace),
         "pi": build_pi_base_urls(workspace),
     }
     return urls
diff --git a/tests/test_agent_copilot.py b/tests/test_agent_copilot.py
index f6fd5136..a1aa9a29 100644
--- a/tests/test_agent_copilot.py
+++ b/tests/test_agent_copilot.py
@@ -4,9 +4,13 @@
 
 import json
 
+import pytest
+
 from ucode.agents import copilot
 
 WS = "https://example.databricks.com"
+# >= MINIMUM_COPILOT_ANTHROPIC_VERSION, for tests that need the anthropic path reachable.
+NEW_ENOUGH_VERSION = "1.0.82"
 
 
 class TestCopilotSpec:
@@ -24,26 +28,187 @@ def test_config_path_is_ucode_env_file(self):
 
 
 class TestRenderEnvOverlay:
-    def test_sets_provider_base_url(self):
+    """Claude models get Copilot's native `anthropic` provider (so Copilot's own
+    cache_control logic runs); everything else (codex/gpt-5) stays on `openai`
+    against the MLflow gateway.
+
+    Verified live against a real workspace: Databricks' AI Gateway 401s on the
+    `x-api-key` auth Copilot's `anthropic` provider sends by default
+    (COPILOT_PROVIDER_API_KEY) — it wants `Authorization: Bearer`
+    (COPILOT_PROVIDER_BEARER_TOKEN, used for both provider types here). And an
+    unrecognized COPILOT_MODEL (a Databricks catalog id) makes Copilot fall
+    back to defaults that include sending `temperature`, which current-gen
+    Claude models 400 on — hence the separate COPILOT_PROVIDER_MODEL_ID
+    (canonical name) / COPILOT_PROVIDER_WIRE_MODEL (actual wire id) split.
+
+    All of that only works on Copilot >= 1.0.81-6 (see TestSupportsAnthropicProvider),
+    so every test here mocks a new-enough installed version."""
+
+    @pytest.fixture(autouse=True)
+    def _new_enough_copilot(self, monkeypatch):
+        monkeypatch.setattr(copilot, "agent_version", lambda binary: NEW_ENOUGH_VERSION)
+
+    def test_claude_model_uses_anthropic_provider_type(self):
         env = copilot.render_env_overlay(WS, "claude-sonnet-4-6", "tok")
-        assert env["COPILOT_PROVIDER_BASE_URL"] == f"{WS}/ai-gateway/mlflow/v1"
+        assert env["COPILOT_PROVIDER_TYPE"] == "anthropic"
+
+    def test_claude_model_uses_native_anthropic_base_url(self):
+        env = copilot.render_env_overlay(WS, "claude-sonnet-4-6", "tok")
+        assert env["COPILOT_PROVIDER_BASE_URL"] == f"{WS}/ai-gateway/anthropic"
+
+    def test_claude_model_sets_bearer_token_not_api_key(self):
+        env = copilot.render_env_overlay(WS, "claude-sonnet-4-6", "tok123")
+        assert env["COPILOT_PROVIDER_BEARER_TOKEN"] == "tok123"
+        assert "COPILOT_PROVIDER_API_KEY" not in env
+
+    def test_claude_model_splits_canonical_id_from_wire_model(self):
+        env = copilot.render_env_overlay(WS, "system.ai.claude-sonnet-5", "tok")
+        assert env["COPILOT_PROVIDER_MODEL_ID"] == "claude-sonnet-5"
+        assert env["COPILOT_PROVIDER_WIRE_MODEL"] == "system.ai.claude-sonnet-5"
+        assert "COPILOT_MODEL" not in env
 
-    def test_sets_provider_type(self):
-        env = copilot.render_env_overlay(WS, "m", "t")
+    def test_claude_model_matches_case_insensitively(self):
+        env = copilot.render_env_overlay(WS, "us.anthropic.Claude-Opus-4-8", "tok")
+        assert env["COPILOT_PROVIDER_TYPE"] == "anthropic"
+        assert env["COPILOT_PROVIDER_MODEL_ID"] == "claude-opus-4-8"
+
+    def test_non_claude_model_uses_openai_provider_type(self):
+        env = copilot.render_env_overlay(WS, "gpt-5", "t")
         assert env["COPILOT_PROVIDER_TYPE"] == "openai"
 
-    def test_sets_model(self):
-        env = copilot.render_env_overlay(WS, "claude-sonnet-4-6", "tok")
-        assert env["COPILOT_MODEL"] == "claude-sonnet-4-6"
+    def test_non_claude_model_uses_mlflow_base_url(self):
+        env = copilot.render_env_overlay(WS, "gpt-5", "t")
+        assert env["COPILOT_PROVIDER_BASE_URL"] == f"{WS}/ai-gateway/mlflow/v1"
 
-    def test_sets_bearer_token(self):
-        env = copilot.render_env_overlay(WS, "m", "tok123")
+    def test_non_claude_model_sets_model_and_bearer_token(self):
+        env = copilot.render_env_overlay(WS, "gpt-5", "tok123")
+        assert env["COPILOT_MODEL"] == "gpt-5"
         assert env["COPILOT_PROVIDER_BEARER_TOKEN"] == "tok123"
+        assert "COPILOT_PROVIDER_API_KEY" not in env
+        assert "COPILOT_PROVIDER_MODEL_ID" not in env
+        assert "COPILOT_PROVIDER_WIRE_MODEL" not in env
 
     def test_sets_offline_true(self):
-        env = copilot.render_env_overlay(WS, "m", "t")
+        env = copilot.render_env_overlay(WS, "gpt-5", "t")
         assert env["COPILOT_OFFLINE"] == "true"
 
+    def test_sets_oauth_token_for_both_families(self):
+        assert copilot.render_env_overlay(WS, "claude-sonnet-4-6", "tok")["OAUTH_TOKEN"] == "tok"
+        assert copilot.render_env_overlay(WS, "gpt-5", "tok")["OAUTH_TOKEN"] == "tok"
+
+
+class TestOldCopilotFallsBackToOpenai:
+    """Below 1.0.81-6, Copilot always sends `temperature` on the anthropic
+    path regardless of model id, and current-gen Claude models 400 on it —
+    verified live (1.0.79, 1.0.80, 1.0.81-0 all fail; 1.0.81-6 onward works).
+    So an old Copilot must keep getting the openai path even for Claude
+    models: uncached, but that's the pre-fix status quo, not a regression."""
+
+    def test_old_version_keeps_claude_on_openai(self, monkeypatch):
+        monkeypatch.setattr(copilot, "agent_version", lambda binary: "1.0.80")
+        env = copilot.render_env_overlay(WS, "system.ai.claude-sonnet-5", "tok")
+        assert env["COPILOT_PROVIDER_TYPE"] == "openai"
+        assert env["COPILOT_MODEL"] == "system.ai.claude-sonnet-5"
+
+    def test_unknown_version_keeps_claude_on_openai(self, monkeypatch):
+        monkeypatch.setattr(copilot, "agent_version", lambda binary: "unknown")
+        env = copilot.render_env_overlay(WS, "system.ai.claude-sonnet-5", "tok")
+        assert env["COPILOT_PROVIDER_TYPE"] == "openai"
+
+    def test_new_enough_version_uses_anthropic(self, monkeypatch):
+        monkeypatch.setattr(copilot, "agent_version", lambda binary: "1.0.81-6")
+        env = copilot.render_env_overlay(WS, "system.ai.claude-sonnet-5", "tok")
+        assert env["COPILOT_PROVIDER_TYPE"] == "anthropic"
+
+
+class TestSupportsAnthropicProvider:
+    def test_false_below_the_minimum_patch(self, monkeypatch):
+        monkeypatch.setattr(copilot, "agent_version", lambda binary: "1.0.80")
+        assert copilot._supports_anthropic_provider() is False
+
+    def test_false_just_below_the_minimum_prerelease(self, monkeypatch):
+        monkeypatch.setattr(copilot, "agent_version", lambda binary: "1.0.81-0")
+        assert copilot._supports_anthropic_provider() is False
+
+    def test_true_at_the_exact_minimum_prerelease(self, monkeypatch):
+        monkeypatch.setattr(copilot, "agent_version", lambda binary: "1.0.81-6")
+        assert copilot._supports_anthropic_provider() is True
+
+    def test_true_above_the_minimum_prerelease(self, monkeypatch):
+        monkeypatch.setattr(copilot, "agent_version", lambda binary: "1.0.81-7")
+        assert copilot._supports_anthropic_provider() is True
+
+    def test_true_for_the_final_release_of_the_minimum_version(self, monkeypatch):
+        monkeypatch.setattr(copilot, "agent_version", lambda binary: "1.0.81")
+        assert copilot._supports_anthropic_provider() is True
+
+    def test_true_for_a_newer_minor_version(self, monkeypatch):
+        monkeypatch.setattr(copilot, "agent_version", lambda binary: "1.0.83")
+        assert copilot._supports_anthropic_provider() is True
+
+    def test_false_when_version_cannot_be_determined(self, monkeypatch):
+        monkeypatch.setattr(copilot, "agent_version", lambda binary: "unknown")
+        assert copilot._supports_anthropic_provider() is False
+
+
+class TestParseCopilotVersion:
+    def test_parses_a_final_release(self):
+        assert copilot._parse_copilot_version("1.0.82") == (1, 0, 82, copilot._UNRELEASED)
+
+    def test_parses_a_prerelease(self):
+        assert copilot._parse_copilot_version("1.0.81-6") == (1, 0, 81, 6)
+
+    def test_a_final_release_sorts_after_its_prereleases(self):
+        final = copilot._parse_copilot_version("1.0.81")
+        prerelease = copilot._parse_copilot_version("1.0.81-14")
+        assert final > prerelease
+
+    def test_returns_none_for_unparseable_input(self):
+        assert copilot._parse_copilot_version("unknown") is None
+
+
+class TestIsClaudeModel:
+    def test_true_for_canonical_name(self):
+        assert copilot._is_claude_model("claude-sonnet-5") is True
+
+    def test_true_for_bedrock_style_slug(self):
+        assert copilot._is_claude_model("us.anthropic.claude-opus-4-8") is True
+
+    def test_false_for_codex(self):
+        assert copilot._is_claude_model("gpt-5") is False
+
+    def test_false_for_catalog_qualified_gpt(self):
+        assert copilot._is_claude_model("system.ai.gpt-5") is False
+
+
+class TestCanonicalClaudeModelId:
+    def test_strips_databricks_catalog_prefix(self):
+        assert copilot._canonical_claude_model_id("system.ai.claude-sonnet-5") == "claude-sonnet-5"
+
+    def test_strips_bedrock_region_and_provider_prefix(self):
+        result = copilot._canonical_claude_model_id("us.anthropic.claude-opus-4-8")
+        assert result == "claude-opus-4-8"
+
+    def test_leaves_bare_canonical_name_unchanged(self):
+        assert copilot._canonical_claude_model_id("claude-haiku-4-5") == "claude-haiku-4-5"
+
+    def test_falls_back_to_the_input_when_no_match(self):
+        assert copilot._canonical_claude_model_id("weird-model") == "weird-model"
+
+    def test_lowercases_a_mixed_case_id(self):
+        assert (
+            copilot._canonical_claude_model_id("us.anthropic.Claude-Opus-4-8") == "claude-opus-4-8"
+        )
+
+    def test_lowercases_the_fallback_when_no_match(self):
+        assert copilot._canonical_claude_model_id("Weird-Model") == "weird-model"
+
+    def test_strips_a_trailing_bedrock_version_suffix(self):
+        assert copilot._canonical_claude_model_id("claude-opus-4-8-v1:0") == "claude-opus-4-8"
+
+    def test_strips_a_bedrock_version_suffix_without_a_colon_part(self):
+        assert copilot._canonical_claude_model_id("claude-opus-4-8-v1") == "claude-opus-4-8"
+
 
 class TestBuildRuntimeEnv:
     def test_inherits_path(self):
@@ -60,6 +225,32 @@ def test_sets_oauth_token_for_mcp(self):
         assert env["OAUTH_TOKEN"] == "tok"
 
 
+class TestWriteToolConfig:
+    def test_switching_families_clears_the_stale_model_selection_keys(self, tmp_path, monkeypatch):
+        import ucode.agents.copilot as cp_mod
+        import ucode.config_io as config_io_mod
+
+        monkeypatch.setattr(config_io_mod, "APP_DIR", tmp_path)
+        env_path = tmp_path / "ucode.env"
+        monkeypatch.setattr(cp_mod, "COPILOT_ENV_PATH", env_path)
+        monkeypatch.setattr(cp_mod, "COPILOT_BACKUP_PATH", tmp_path / "backup")
+        monkeypatch.setattr(cp_mod, "save_state", lambda state: None)
+        monkeypatch.setattr(cp_mod, "agent_version", lambda binary: NEW_ENOUGH_VERSION)
+
+        state = {"workspace": WS}
+        cp_mod.write_tool_config(state, "system.ai.claude-sonnet-5", token="tok-a")
+        written = config_io_mod.parse_dotenv(env_path)
+        assert written["COPILOT_PROVIDER_MODEL_ID"] == "claude-sonnet-5"
+        assert written["COPILOT_PROVIDER_WIRE_MODEL"] == "system.ai.claude-sonnet-5"
+        assert "COPILOT_MODEL" not in written
+
+        cp_mod.write_tool_config(state, "gpt-5", token="tok-b")
+        written = config_io_mod.parse_dotenv(env_path)
+        assert written["COPILOT_MODEL"] == "gpt-5"
+        assert "COPILOT_PROVIDER_MODEL_ID" not in written
+        assert "COPILOT_PROVIDER_WIRE_MODEL" not in written
+
+
 class TestMcpServerConfig:
     # ucode registers the `ucode mcp-proxy ...` bridge as a `local` (stdio) MCP
     # server; the proxy refreshes the token, so no URL/bearer header here.
@@ -191,6 +382,8 @@ def test_includes_required_vars(self):
             "COPILOT_PROVIDER_TYPE",
             "COPILOT_PROVIDER_BASE_URL",
             "COPILOT_MODEL",
+            "COPILOT_PROVIDER_MODEL_ID",
+            "COPILOT_PROVIDER_WIRE_MODEL",
             "COPILOT_PROVIDER_BEARER_TOKEN",
             "COPILOT_OFFLINE",
             "OAUTH_TOKEN",
diff --git a/tests/test_databricks.py b/tests/test_databricks.py
index ffd9636b..0a083b3c 100644
--- a/tests/test_databricks.py
+++ b/tests/test_databricks.py
@@ -21,6 +21,7 @@
     all_users_can_use_schema,
     build_auth_shell_command,
     build_auth_token_argv,
+    build_copilot_base_urls,
     build_databricks_cli_env,
     build_opencode_base_urls,
     build_shared_base_urls,
@@ -115,6 +116,10 @@ def test_opencode_raises(self):
         with pytest.raises(RuntimeError, match="multiple base URLs"):
             build_tool_base_url("opencode", WS)
 
+    def test_copilot_raises(self):
+        with pytest.raises(RuntimeError, match="multiple base URLs"):
+            build_tool_base_url("copilot", WS)
+
     def test_unsupported_tool_raises(self):
         with pytest.raises(RuntimeError, match="Unsupported"):
             build_tool_base_url("unknown", WS)
@@ -128,6 +133,16 @@ def test_returns_anthropic_gemini_and_oss(self):
         assert urls["oss"] == f"{WS}/ai-gateway/mlflow/v1"
 
 
+class TestBuildCopilotBaseUrls:
+    def test_anthropic_points_at_the_native_claude_gateway(self):
+        urls = build_copilot_base_urls(WS)
+        assert urls["anthropic"] == f"{WS}/ai-gateway/anthropic"
+
+    def test_openai_points_at_the_mlflow_gateway(self):
+        urls = build_copilot_base_urls(WS)
+        assert urls["openai"] == f"{WS}/ai-gateway/mlflow/v1"
+
+
 class TestBuildSharedBaseUrls:
     def test_contains_all_tools(self):
         urls = build_shared_base_urls(WS)
@@ -135,11 +150,16 @@ def test_contains_all_tools(self):
         assert "claude" in urls
         assert "gemini" in urls
         assert "opencode" in urls
+        assert "copilot" in urls
 
     def test_opencode_is_dict(self):
         urls = build_shared_base_urls(WS)
         assert isinstance(urls["opencode"], dict)
 
+    def test_copilot_is_dict(self):
+        urls = build_shared_base_urls(WS)
+        assert isinstance(urls["copilot"], dict)
+
     def test_codex_url_format(self):
         urls = build_shared_base_urls(WS)
         assert urls["codex"] == f"{WS}/ai-gateway/codex/v1"