feat(mcp-augment): implement AugmentAdapter

New adapter for Augment Code (auggie CLI + extensions) following the
LMStudio pattern. Validates exactly-one transport (command XOR url)
and type-field consistency (type=stdio requires command, etc.).
No field mappings or structural transforms needed.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: LittleCoinCoin

hatch/mcp_host_config/adapters/augment.py

@@ -0,0 +1,119 @@
+"""Augment Code adapter for MCP host configuration.
+
+Augment Code (auggie CLI + extensions) uses the same field set as Claude:
+command/args/env for stdio, url/headers for sse/http, with optional type discriminator.
+Config file: ~/.augment/settings.json, root key: mcpServers.
+"""
+
+from typing import Any, Dict, FrozenSet
+
+from hatch.mcp_host_config.adapters.base import AdapterValidationError, BaseAdapter
+from hatch.mcp_host_config.fields import AUGMENT_FIELDS
+from hatch.mcp_host_config.models import MCPServerConfig
+
+
+class AugmentAdapter(BaseAdapter):
+    """Adapter for Augment Code MCP host.
+
+    Augment Code uses the same configuration format as Claude:
+    - Supports 'type' field for transport discrimination
+    - Requires exactly one transport (command XOR url)
+    """
+
+    @property
+    def host_name(self) -> str:
+        """Return the host identifier."""
+        return "augment"
+
+    def get_supported_fields(self) -> FrozenSet[str]:
+        """Return fields supported by Augment Code."""
+        return AUGMENT_FIELDS
+
+    def validate(self, config: MCPServerConfig) -> None:
+        """Validate configuration for Augment Code.
+
+        DEPRECATED: This method is deprecated and will be removed in v0.9.0.
+        Use validate_filtered() instead.
+        """
+        has_command = config.command is not None
+        has_url = config.url is not None
+
+        if not has_command and not has_url:
+            raise AdapterValidationError(
+                "Either 'command' (local) or 'url' (remote) must be specified",
+                host_name=self.host_name,
+            )
+
+        if has_command and has_url:
+            raise AdapterValidationError(
+                "Cannot specify both 'command' and 'url' - choose one transport",
+                host_name=self.host_name,
+            )
+
+        if config.type is not None:
+            if config.type == "stdio" and not has_command:
+                raise AdapterValidationError(
+                    "type='stdio' requires 'command' field",
+                    field="type",
+                    host_name=self.host_name,
+                )
+            if config.type in ("sse", "http") and not has_url:
+                raise AdapterValidationError(
+                    f"type='{config.type}' requires 'url' field",
+                    field="type",
+                    host_name=self.host_name,
+                )
+
+    def validate_filtered(self, filtered: Dict[str, Any]) -> None:
+        """Validate filtered configuration for Augment Code.
+
+        Validates only fields that survived filtering (supported by Augment).
+        Augment Code requires exactly one transport (command XOR url).
+
+        Args:
+            filtered: Dictionary of filtered fields
+
+        Raises:
+            AdapterValidationError: If validation fails
+        """
+        has_command = "command" in filtered
+        has_url = "url" in filtered
+
+        if not has_command and not has_url:
+            raise AdapterValidationError(
+                "Either 'command' (local) or 'url' (remote) must be specified",
+                host_name=self.host_name,
+            )
+
+        if has_command and has_url:
+            raise AdapterValidationError(
+                "Cannot specify both 'command' and 'url' - choose one transport",
+                host_name=self.host_name,
+            )
+
+        if "type" in filtered:
+            config_type = filtered["type"]
+            if config_type == "stdio" and not has_command:
+                raise AdapterValidationError(
+                    "type='stdio' requires 'command' field",
+                    field="type",
+                    host_name=self.host_name,
+                )
+            if config_type in ("sse", "http") and not has_url:
+                raise AdapterValidationError(
+                    f"type='{config_type}' requires 'url' field",
+                    field="type",
+                    host_name=self.host_name,
+                )
+
+    def serialize(self, config: MCPServerConfig) -> Dict[str, Any]:
+        """Serialize configuration for Augment Code format.
+
+        Follows the validate-after-filter pattern:
+        1. Filter to supported fields
+        2. Validate filtered fields
+        3. Return filtered (no transformations needed)
+        """
+        filtered = self.filter_fields(config)
+        self.validate_filtered(filtered)
+        return filtered