Add Generation Parameter (MooshieUI)

---
name: add-generation-param-2ffdecbe1518
description: >-
  Adds a generation parameter across MooshieUI's Svelte store, TypeScript types,
  Rust GenerationParams, and workflow templates. Use for new UI settings, ComfyUI
  inputs, or /add-generation-param.
model: sonnet
---

# Add Generation Parameter (MooshieUI)

**6 touchpoints**, in order. New workflow-only params still need Rust + TS types if exposed in UI.

## Gather from user

1. Name (TS `camelCase`, Rust/iface `snake_case`)
2. Type + default
3. Templates: txt2img | img2img | inpainting | upscale | all
4. ComfyUI node + input field name

## 1. `src/lib/types/index.ts`

```typescript
export interface GenerationParams {
  new_param: SomeType;
}
```

## 2–4. `src/lib/stores/generation.svelte.ts`

```typescript
newParam = $state<SomeType>(defaultValue);

// loadSettings()
if (saved.newParam !== undefined) this.newParam = saved.newParam;

// saveSettings()
newParam: this.newParam,

// toParams()
new_param: this.newParam,
```

Use `!== undefined` for bool/number defaults that can be `0` or `false`.

## 5. `src-tauri/src/comfyui/types.rs`

```rust
pub new_param: Type,
// or
pub new_param: Option<Type>,
```

## 6. `src-tauri/src/templates/{mode}.rs`

```rust
"node_input": params.new_param,
```

## 7. MCP check — `src-tauri/src/mcp/setups.rs`

The MCP server reuses the owner's last txt2img request per model (see `docs/MCP.md`). Decide which case the param is:

- **Points at one image** (ComfyUI input filename, mask, reference): clear it in `snapshot()`, or assistants re-send a stale file.
- **Something an assistant should set** (like steps or size): add it to `Overrides`, `apply()` (with bounds) and the `generate_image` schema in `mcp/tools.rs`, plus a test.
- **Neither** (a tuning knob the setup should carry over): nothing to do.

## Verify

```powershell
cargo check --manifest-path src-tauri/Cargo.toml
```

```
- [ ] Interface snake_case field
- [ ] Store $state + load/save + toParams()
- [ ] Rust GenerationParams field
- [ ] ≥1 template references param
- [ ] MCP check done (snapshot / Overrides / nothing)
```

If UI needs i18n: add keys to **all** files in `src/lib/locales/` (parity with `en.ts`).

For new workflow **modes**, use **workflow-template-builder** skill after params exist.