diff --git a/tests/test_identity_contract.py b/tests/test_identity_contract.py
index 78f118be..3783df30 100644
--- a/tests/test_identity_contract.py
+++ b/tests/test_identity_contract.py
@@ -175,6 +175,83 @@ def test_deregister_uses_authenticated_identity_not_path_text(self):
 
 
 class WrapperLaunchTests(unittest.TestCase):
+    def test_named_claude_identity_derives_injection_from_command(self):
+        with tempfile.TemporaryDirectory() as tmp:
+            args, _env, inject_env, settings_path = wrapper._build_provider_launch(
+                agent="claude2",
+                agent_cfg={"command": "claude"},
+                instance_name="claude2",
+                data_dir=Path(tmp),
+                proxy_url=None,
+                extra_args=[],
+                env={},
+                token="named_claude_token",
+                mcp_cfg={"http_port": 8200},
+            )
+
+            self.assertEqual(args[:1], ["--mcp-config"])
+            self.assertEqual(inject_env, {})
+            payload = json.loads(Path(settings_path).read_text("utf-8"))
+            self.assertEqual(
+                payload["mcpServers"]["agentchattr"]["headers"]["Authorization"],
+                "Bearer named_claude_token",
+            )
+
+    def test_named_codex_identity_derives_injection_from_command_path(self):
+        args, _env, inject_env, settings_path = wrapper._build_provider_launch(
+            agent="codex2",
+            agent_cfg={"command": r"C:\Tools\codex.exe"},
+            instance_name="codex2",
+            data_dir=Path(tempfile.gettempdir()),
+            proxy_url="http://127.0.0.1:7777/mcp",
+            extra_args=[],
+            env={},
+        )
+
+        self.assertEqual(args[0], "-c")
+        self.assertIn('mcp_servers.agentchattr.url="http://127.0.0.1:7777/mcp"', args[1])
+        self.assertEqual(inject_env, {})
+        self.assertIsNone(settings_path)
+
+    def test_command_exe_suffix_resolves_provider_defaults(self):
+        resolved = wrapper._resolve_mcp_inject("claude2", {"command": "claude.exe"})
+
+        self.assertEqual(resolved["mcp_inject"], "flag")
+        self.assertEqual(resolved["mcp_flag"], "--mcp-config")
+
+    def test_explicit_mcp_override_precedes_command_provider_defaults(self):
+        resolved = wrapper._resolve_mcp_inject(
+            "claude2",
+            {
+                "command": "claude",
+                "mcp_inject": "proxy_flag",
+                "mcp_proxy_flag_template": "--server={url}",
+            },
+        )
+
+        self.assertEqual(resolved["mcp_inject"], "proxy_flag")
+        self.assertEqual(resolved["mcp_proxy_flag_template"], "--server={url}")
+        self.assertNotIn("mcp_flag", resolved)
+
+    def test_named_provider_merges_partial_mcp_overrides(self):
+        resolved = wrapper._resolve_mcp_inject(
+            "claude2",
+            {"command": "claude", "mcp_transport": "sse", "mcp_flag": "--custom"},
+        )
+
+        self.assertEqual(resolved["mcp_inject"], "flag")
+        self.assertEqual(resolved["mcp_transport"], "sse")
+        self.assertEqual(resolved["mcp_flag"], "--custom")
+
+    def test_unknown_custom_command_does_not_inherit_provider_defaults(self):
+        self.assertEqual(
+            wrapper._resolve_mcp_inject(
+                "custom-agent",
+                {"command": "claude-compatible"},
+            ),
+            {},
+        )
+
     def test_build_provider_launch_for_claude_uses_direct_server_auth(self):
         """Claude bypasses proxy — connects directly to MCP server with bearer token."""
         with tempfile.TemporaryDirectory() as tmp:
diff --git a/wrapper.py b/wrapper.py
index c7fde420..c256128a 100644
--- a/wrapper.py
+++ b/wrapper.py
@@ -163,13 +163,32 @@ def _write_claude_mcp_config(
 _VALID_INJECT_MODES = {"settings_file", "env", "flag", "proxy_flag", "env_content"}
 
 
+def _provider_from_command(command: object) -> str:
+    """Return a built-in provider for an exact configured executable name.
+
+    Named agent identities (for example ``claude2``) are independent of
+    the CLI they launch.  Resolve only exact known executable basenames; do
+    not guess from prefixes or arbitrary command text.
+    """
+    if not isinstance(command, str):
+        return ""
+    executable = command.strip().replace("\\", "/").rsplit("/", 1)[-1].lower()
+    for suffix in (".exe", ".cmd", ".bat"):
+        if executable.endswith(suffix):
+            executable = executable[:-len(suffix)]
+            break
+    return executable if executable in _BUILTIN_DEFAULTS else ""
+
+
 def _resolve_mcp_inject(agent: str, agent_cfg: dict) -> dict:
-    """Resolve MCP injection config: explicit agent_cfg > built-in defaults > None."""
-    inject_mode = agent_cfg.get("mcp_inject")
-    if inject_mode:
+    """Resolve MCP injection config: explicit config > provider defaults > none."""
+    if agent_cfg.get("mcp_inject"):
         return dict(agent_cfg)
-    if agent in _BUILTIN_DEFAULTS:
-        merged = dict(_BUILTIN_DEFAULTS[agent])
+    provider = agent
+    if provider not in _BUILTIN_DEFAULTS:
+        provider = _provider_from_command(agent_cfg.get("command", ""))
+    if provider:
+        merged = dict(_BUILTIN_DEFAULTS[provider])
         merged.update({k: v for k, v in agent_cfg.items() if k.startswith("mcp_")})
         return merged
     return {}