feat(mcp-host-config): add field support constants

Author: LittleCoinCoin

hatch/mcp_host_config/fields.py

@@ -0,0 +1,126 @@
+"""
+Field constants for MCP host configuration adapter architecture.
+
+This module defines the source of truth for field support across MCP hosts.
+All adapters reference these constants to determine field filtering and mapping.
+"""
+
+from typing import FrozenSet
+from enum import Enum
+
+
+# ============================================================================
+# Universal Fields (supported by ALL hosts)
+# ============================================================================
+
+UNIVERSAL_FIELDS: FrozenSet[str] = frozenset({
+    "command",  # Executable path/name for local servers
+    "args",     # Command arguments for local servers
+    "env",      # Environment variables (all transports)
+    "url",      # Server endpoint URL for remote servers (SSE transport)
+    "headers",  # HTTP headers for remote servers
+})
+
+
+# ============================================================================
+# Type Field Support
+# ============================================================================
+
+# Hosts that support the 'type' discriminator field (stdio/sse/http)
+# Note: Gemini, Kiro, Codex do NOT support this field
+TYPE_SUPPORTING_HOSTS: FrozenSet[str] = frozenset({
+    "claude-desktop",
+    "claude-code",
+    "vscode",
+    "cursor",
+})
+
+
+# ============================================================================
+# Host-Specific Field Sets
+# ============================================================================
+
+# Fields supported by Claude Desktop/Code (universal + type)
+CLAUDE_FIELDS: FrozenSet[str] = UNIVERSAL_FIELDS | frozenset({
+    "type",  # Transport discriminator
+})
+
+# Fields supported by VSCode (Claude fields + envFile + inputs)
+VSCODE_FIELDS: FrozenSet[str] = CLAUDE_FIELDS | frozenset({
+    "envFile",  # Path to environment file
+    "inputs",   # Input variable definitions (VSCode only)
+})
+
+# Fields supported by Cursor (Claude fields + envFile, no inputs)
+CURSOR_FIELDS: FrozenSet[str] = CLAUDE_FIELDS | frozenset({
+    "envFile",  # Path to environment file
+})
+
+# Fields supported by LMStudio (universal + type)
+LMSTUDIO_FIELDS: FrozenSet[str] = CLAUDE_FIELDS
+
+# Fields supported by Gemini (no type field, but has httpUrl and others)
+GEMINI_FIELDS: FrozenSet[str] = UNIVERSAL_FIELDS | frozenset({
+    "httpUrl",       # HTTP streaming endpoint URL
+    "timeout",       # Request timeout in milliseconds
+    "trust",         # Bypass tool call confirmations
+    "cwd",           # Working directory for stdio transport
+    "includeTools",  # Tools to include (allowlist)
+    "excludeTools",  # Tools to exclude (blocklist)
+    # OAuth configuration
+    "oauth_enabled",
+    "oauth_clientId",
+    "oauth_clientSecret",
+    "oauth_authorizationUrl",
+    "oauth_tokenUrl",
+    "oauth_scopes",
+    "oauth_redirectUri",
+    "oauth_tokenParamName",
+    "oauth_audiences",
+    "authProviderType",
+})
+
+# Fields supported by Kiro (no type field)
+KIRO_FIELDS: FrozenSet[str] = UNIVERSAL_FIELDS | frozenset({
+    "disabled",       # Whether server is disabled
+    "autoApprove",    # Auto-approved tool names
+    "disabledTools",  # Disabled tool names
+})
+
+# Fields supported by Codex (no type field, has field mappings)
+CODEX_FIELDS: FrozenSet[str] = UNIVERSAL_FIELDS | frozenset({
+    "cwd",                 # Working directory
+    "env_vars",            # Environment variables to whitelist/forward
+    "startup_timeout_sec", # Server startup timeout
+    "tool_timeout_sec",    # Tool execution timeout
+    "enabled",             # Enable/disable server
+    "enabled_tools",       # Allow-list of tools
+    "disabled_tools",      # Deny-list of tools
+    "bearer_token_env_var",# Env var containing bearer token
+    "http_headers",        # HTTP headers (Codex naming)
+    "env_http_headers",    # Header names to env var names mapping
+})
+
+
+# ============================================================================
+# Field Mappings (universal name → host-specific name)
+# ============================================================================
+
+# Codex uses different field names for some universal/shared fields
+CODEX_FIELD_MAPPINGS: dict[str, str] = {
+    "args": "arguments",          # Codex uses 'arguments' instead of 'args'
+    "headers": "http_headers",    # Codex uses 'http_headers' instead of 'headers'
+    "includeTools": "enabled_tools",   # Gemini naming → Codex naming
+    "excludeTools": "disabled_tools",  # Gemini naming → Codex naming
+}
+
+
+# ============================================================================
+# Metadata Fields (never serialized to host config files)
+# ============================================================================
+
+# Fields that are Hatch metadata and should NEVER appear in serialized output
+EXCLUDED_ALWAYS: FrozenSet[str] = frozenset({
+    "name",  # Server name is key in the config dict, not a field value
+})
+