feat: support default values for input definitions (#70)

Signed-off-by: Mohammod Al Amin Ashik <maa.ashik00@gmail.com>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: its-mash

CLAUDE.md

@@ -0,0 +1,167 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Codebase Search
+
+This repository is indexed for semantic code search via the `claude-context` MCP server. Prefer `mcp__claude-context__search_code` (with path `D:\mcpmux`) over Grep/Glob when looking for implementations, understanding how features work, or finding related code across the codebase. Use Grep/Glob for exact string matches or filename patterns. If search returns an indexing error, re-index with `mcp__claude-context__index_codebase` first.
+
+## What is McpMux
+
+McpMux is a desktop app + local gateway that lets users configure MCP servers once and connect every AI client (Cursor, Claude Desktop, VS Code, Windsurf) through a single `localhost:45818` endpoint. Credentials are encrypted in the OS keychain instead of plain-text JSON files.
+
+## Repository Structure
+
+This is a multi-project workspace with 6 independent projects (not a unified monorepo):
+
+| Project | Tech | Purpose |
+|---------|------|---------|
+| `mcp-mux/` | Tauri 2 (Rust + React 19), pnpm workspace | Desktop app + local MCP gateway |
+| `mcpmux.bundler/` | Cloudflare Worker | GitHub webhook receiver that processes server definitions into D1/R2 |
+| `mcpmux.serverhub.api/` | Cloudflare Worker (Hono) | REST API for server registry discovery (KV -> D1 -> R2 fallback chain) |
+| `mcpmux.discover.ui/` | Next.js 16, shadcn/ui, Tailwind 4 | Web UI for browsing the server registry |
+| `mcp-servers/` | JSON + AJV validation | Community MCP server definitions repository |
+| `mcpmux.space/` | Docs | Documentation and design space |
+
+## mcp-mux (Desktop App) - Main Project
+
+### Build & Dev Commands
+
+All commands run from `mcp-mux/`:
+
+```bash
+pnpm setup              # First-time dev environment setup (PowerShell)
+pnpm dev                # Tauri desktop app dev mode (Rust + React hot-reload)
+pnpm dev:web            # Web UI only (Vite, no Rust)
+pnpm build              # Production Tauri build (all platforms)
+```
+
+### Testing
+
+```bash
+pnpm test               # All tests (Rust + TypeScript)
+pnpm test:rust          # cargo nextest run --workspace
+pnpm test:rust:unit     # cargo nextest run --workspace --lib
+pnpm test:rust:int      # cargo nextest run -p tests
+pnpm test:rust:doc      # cargo test --workspace --doc
+pnpm test:ts            # vitest run -c tests/ts/vitest.config.ts
+pnpm test:ts:watch      # vitest watch mode
+pnpm test:e2e           # WebDriver IO desktop E2E (needs MCPMUX_REGISTRY_URL)
+pnpm test:e2e:file      # Single E2E spec: pnpm test:e2e:file -- tests/e2e/specs/foo.ts
+pnpm test:e2e:grep      # E2E by name: pnpm test:e2e:grep -- "test name"
+pnpm test:e2e:web       # Playwright web UI E2E
+pnpm test:coverage      # cargo llvm-cov + vitest coverage
+```
+
+### Linting & Validation
+
+```bash
+pnpm validate           # Full check: cargo fmt + clippy + check + eslint + typecheck
+pnpm lint               # ESLint (recursive) + cargo clippy --workspace -- -D warnings
+pnpm lint:fix           # Auto-fix lint issues
+pnpm format             # prettier --write . && cargo fmt --all
+pnpm format:check       # Check formatting without modifying
+pnpm typecheck          # TypeScript type checking (recursive)
+```
+
+### Rust Crate Architecture
+
+The Cargo workspace has 4 library crates + 1 app crate + 1 test crate:
+
+- **mcpmux-core** (`crates/mcpmux-core/`) - Domain layer: entities (Space, InstalledServer, FeatureSet, Client), repository traits, domain services, application services with event emission, and the central EventBus
+- **mcpmux-gateway** (`crates/mcpmux-gateway/`) - Axum HTTP gateway: routes MCP calls to correct servers, manages OAuth 2.1+PKCE token refresh, filters tools/resources/prompts based on FeatureSets, per-client access key auth, server connection pooling
+- **mcpmux-storage** (`crates/mcpmux-storage/`) - SQLite persistence with AES-256-GCM field-level encryption via ring, typed credential rows (per-token encryption), DPAPI key storage on Windows (`keychain_dpapi.rs`), OS keychain on macOS/Linux via keyring crate, zeroize for secure memory clearing
+- **mcpmux-mcp** (`crates/mcpmux-mcp/`) - MCP protocol client management using rmcp SDK
+- **apps/desktop/src-tauri** - Tauri 2 app shell, Tauri commands, system tray, deep-link handler (`mcpmux://`)
+- **tests/rust** - Integration test crate
+
+Key patterns: event-driven architecture (EventBus), repository pattern (trait-based storage abstraction), service layer pattern with DI via ApplicationServices builders.
+
+### Frontend Architecture
+
+- **Entry**: `apps/desktop/src/main.tsx` -> `App.tsx`
+- **State**: Zustand store (`stores/appStore.ts`)
+- **Hooks**: `useServerManager` (server CRUD), `useSpaces` (workspace switching), `useDomainEvents` (Rust event listeners), `useDataSync` (data synchronization)
+- **UI**: React 19 + Tailwind CSS + Lucide icons + Monaco Editor (config editing)
+- **Path aliases**: `@/` -> `src/`, `@mcpmux/ui` -> shared UI package
+
+### Data Flow
+
+```
+AI Clients -> McpMux Gateway (localhost:45818/mcp) -> MCP Servers (stdio/HTTP)
+                     |
+              Authenticates (access keys)
+              Routes (per-space server config)
+              Filters (FeatureSet permissions)
+              OAuth token refresh (automatic)
+              Credentials (DPAPI files on Windows / OS Keychain on macOS+Linux + encrypted SQLite)
+```
+
+### Prerequisites
+
+Rust 1.75+, Node.js 20+, pnpm 9+. Linux: `gnome-keyring libsecret-1-dev librsvg2-dev pkg-config`.
+
+### Code Style
+
+- Rust: 100 char max width, 4-space indent, `clippy` with `avoid-breaking-exported-api = false`
+- TypeScript/JSX: Prettier with single quotes, 2-space indent, 100 char width, trailing commas (es5), Tailwind CSS plugin
+- Commits require `Signed-off-by` line (use `git commit -s`)
+
+## mcp-servers (Server Definitions Repository)
+
+All commands run from `mcp-servers/` (sibling repo):
+
+```bash
+pnpm install            # Install dependencies (vitest, ajv, glob)
+pnpm validate:all       # Validate all server definitions against JSON schema
+pnpm validate <file>    # Validate specific server definition file(s)
+pnpm build              # Build registry bundle (bundle/bundle.json)
+pnpm test               # Run all tests (schema validation, consistency, categories, bundle)
+```
+
+The JSON schema at `schemas/server-definition.schema.json` defines the structure for server definitions in `servers/`. Input definitions support: `id`, `label`, `type`, `required`, `secret`, `description`, `default`, `placeholder`, and `obtain` (with `url`, `instructions`, `button_label`).
+
+## Cloudflare Workers
+
+Each worker is an independent project with its own `package.json`:
+
+**mcpmux.serverhub.api/** - Hono-based registry API:
+```bash
+cd mcpmux.serverhub.api && pnpm dev    # wrangler dev
+cd mcpmux.serverhub.api && pnpm test   # vitest (cloudflare pool)
+```
+
+**mcpmux.bundler/** - Webhook-triggered bundle processor:
+```bash
+cd mcpmux.bundler && pnpm dev          # wrangler dev
+cd mcpmux.bundler && pnpm test         # vitest run
+```
+
+## mcpmux.discover.ui (Discovery Web UI)
+
+```bash
+cd mcpmux.discover.ui && pnpm dev      # next dev
+cd mcpmux.discover.ui && pnpm test     # vitest
+cd mcpmux.discover.ui && pnpm test:e2e # playwright
+```
+
+## Important Patterns
+
+### Child Process Platform Flags
+
+When spawning child processes (e.g., stdio MCP servers), **always** use `configure_child_process_platform()` from `mcpmux_gateway::pool::transport`. This applies:
+- **Windows**: `CREATE_NO_WINDOW` (`0x08000000`) — prevents visible console windows in release builds (where `windows_subsystem = "windows"` means the app is a GUI subsystem process)
+- **Unix**: `process_group(0)` — isolates child from parent terminal signals (SIGINT, SIGTSTP)
+
+Note: `tokio::process::Command` already exposes `creation_flags()` (Windows) and `process_group()` (Unix) natively — do **not** import `std::os::unix::process::CommandExt` or `std::os::windows::process::CommandExt` as the traits are unused with Tokio's Command.
+
+### Cross-Platform CI Awareness
+
+The pre-commit hook runs `cargo clippy --workspace -- -D warnings` locally, but `#[cfg(unix)]` / `#[cfg(windows)]` blocks are only compiled on the matching platform. **CI runs on Linux**, so:
+- `#[cfg(unix)]` code is only linted in CI, not on a Windows dev machine
+- `#[cfg(windows)]` code is only linted locally on Windows, not in CI
+- Always validate that platform-conditional code compiles correctly on both platforms before pushing
+
+## CI
+
+GitHub Actions runs on push/PR to main: Rust format + clippy + check, ESLint + typecheck, cargo nextest, vitest, desktop E2E (Windows/macOS/Linux), web E2E (Playwright). Releases use release-please for semantic versioning with multi-platform Tauri builds.

crates/mcpmux-core/src/domain/config.rs

@@ -254,6 +254,7 @@ impl UserServerEntry {
                     required: true,
                     secret: true,
                     description: None,
+                    default: None,
                     placeholder: None,
                     obtain_url: None,
                     obtain_instructions: None,
@@ -444,6 +445,7 @@ mod tests {
                     required: false,
                     secret: false,
                     description: Some("Custom description".to_string()),
+                    default: None,
                     placeholder: None,
                     obtain_url: None,
                     obtain_instructions: None,
@@ -649,4 +651,133 @@ mod tests {
         // Explicit OAuth should not be overridden
         assert!(matches!(def.auth, Some(AuthConfig::Oauth)));
     }
+
+    #[test]
+    fn test_input_default_value_parsed_from_json() {
+        let json = r#"{
+            "mcpServers": {
+                "test-server": {
+                    "command": "node",
+                    "args": ["server.js"],
+                    "env": {
+                        "LOG_LEVEL": "${input:LOG_LEVEL}"
+                    },
+                    "metadata": {
+                        "inputs": [
+                            {
+                                "id": "LOG_LEVEL",
+                                "label": "Log Level",
+                                "type": "text",
+                                "required": false,
+                                "secret": false,
+                                "default": "info"
+                            }
+                        ]
+                    }
+                }
+            }
+        }"#;
+
+        let config: UserSpaceConfig = serde_json::from_str(json).unwrap();
+        let definitions =
+            config.to_server_definitions("test-space", PathBuf::from("/test/path.json"));
+
+        assert_eq!(definitions.len(), 1);
+        let inputs = &definitions[0].transport.metadata().inputs;
+        assert_eq!(inputs.len(), 1);
+        assert_eq!(inputs[0].id, "LOG_LEVEL");
+        assert_eq!(inputs[0].default, Some("info".to_string()));
+    }
+
+    #[test]
+    fn test_explicit_input_with_default_takes_precedence_over_autodiscovery() {
+        let entry = UserServerEntry {
+            command: Some("node".to_string()),
+            args: None,
+            env: Some(HashMap::from([(
+                "LOG_LEVEL".to_string(),
+                "${input:LOG_LEVEL}".to_string(),
+            )])),
+            url: None,
+            headers: None,
+            name: None,
+            description: None,
+            icon: None,
+            alias: None,
+            auth: None,
+            metadata: Some(UserServerMetadata {
+                inputs: Some(vec![InputDefinition {
+                    id: "LOG_LEVEL".to_string(),
+                    label: "Log Level".to_string(),
+                    r#type: "text".to_string(),
+                    required: false,
+                    secret: false,
+                    description: None,
+                    default: Some("info".to_string()),
+                    placeholder: None,
+                    obtain_url: None,
+                    obtain_instructions: None,
+                }]),
+                publisher: None,
+            }),
+        };
+
+        let (_, inputs) = entry.resolve_transport_and_inputs();
+
+        assert_eq!(inputs.len(), 1);
+        assert_eq!(inputs[0].id, "LOG_LEVEL");
+        assert_eq!(inputs[0].default, Some("info".to_string()));
+        // Should use explicit definition's type, not auto-discovered "password"
+        assert_eq!(inputs[0].r#type, "text");
+        assert!(!inputs[0].required);
+        assert!(!inputs[0].secret);
+    }
+
+    #[test]
+    fn test_auto_discovered_inputs_have_no_default() {
+        let entry = UserServerEntry {
+            command: Some("node".to_string()),
+            args: None,
+            env: Some(HashMap::from([(
+                "API_KEY".to_string(),
+                "${input:API_KEY}".to_string(),
+            )])),
+            url: None,
+            headers: None,
+            name: None,
+            description: None,
+            icon: None,
+            alias: None,
+            auth: None,
+            metadata: None,
+        };
+
+        let (_, inputs) = entry.resolve_transport_and_inputs();
+
+        assert_eq!(inputs.len(), 1);
+        assert_eq!(inputs[0].id, "API_KEY");
+        assert_eq!(inputs[0].default, None);
+    }
+
+    #[test]
+    fn test_input_default_serializes_roundtrip() {
+        let input = InputDefinition {
+            id: "PORT".to_string(),
+            label: "Port".to_string(),
+            r#type: "number".to_string(),
+            required: false,
+            secret: false,
+            description: None,
+            default: Some("8080".to_string()),
+            placeholder: None,
+            obtain_url: None,
+            obtain_instructions: None,
+        };
+
+        let json = serde_json::to_string(&input).unwrap();
+        let deserialized: InputDefinition = serde_json::from_str(&json).unwrap();
+
+        assert_eq!(deserialized.id, "PORT");
+        assert_eq!(deserialized.default, Some("8080".to_string()));
+    }
 }

crates/mcpmux-core/src/domain/server.rs

@@ -146,6 +146,7 @@ pub struct InputDefinition {
     #[serde(default)]
     pub secret: bool,
     pub description: Option<String>,
+    pub default: Option<String>,
     pub placeholder: Option<String>,
 
     // Additional helpful metadata for acquiring credentials