docs(image-generation): document Cursor GenerateImage backend

docs/creating-skills.md

@@ -165,11 +165,11 @@ Standard snippet (copy verbatim):
 
 When this skill needs to render an image:
 
-- **Use whatever image-generation tool or skill is available** in the current runtime — e.g., Codex `imagegen`, Hermes `image_generate`, `baoyu-image-gen`, or any equivalent the user has installed.
+- **Use whatever image-generation tool or skill is available** in the current runtime — e.g., Codex `imagegen`, Cursor `GenerateImage`, Hermes `image_generate`, `baoyu-image-gen`, or any equivalent the user has installed.
 - **If multiple are available**, ask the user **once** at the start which to use (batch with any other initial questions).
 - **If none are available**, tell the user and ask how to proceed.
 
 **Prompt file requirement (hard)**: write each image's full, final prompt to a standalone file under `prompts/` (naming: `NN-{type}-[slug].md`) BEFORE invoking any backend. The backend receives the prompt file (or its content); the file is the reproducibility record and lets you switch backends without regenerating prompts.
 
-Concrete tool names (`imagegen`, `image_generate`, `baoyu-image-gen`) above are examples — substitute the local equivalents under the same rule.
+Concrete tool names (`imagegen`, `GenerateImage`, `image_generate`, `baoyu-image-gen`) above are examples — substitute the local equivalents under the same rule.
 ```

docs/image-generation-tools.md

@@ -1,6 +1,6 @@
 # Image Generation Tools
 
-Skills in this repo are loaded by multiple agent runtimes (Claude Code, Codex, Hermes, other agents, bare CLI). Each runtime exposes a different image-generation capability — some have a runtime-native tool (Codex `imagegen`, Hermes `image_generate`), others rely on an installed skill (`baoyu-image-gen`, or user-defined). This document defines the canonical **backend-selection rule** every skill that renders images follows so skills stay portable.
+Skills in this repo are loaded by multiple agent runtimes (Claude Code, Codex, Cursor, Hermes, other agents, bare CLI). Each runtime exposes a different image-generation capability — some have a runtime-native tool (Codex `imagegen`, Cursor `GenerateImage`, Hermes `image_generate`), others rely on an installed skill (`baoyu-image-gen`, or user-defined). This document defines the canonical **backend-selection rule** every skill that renders images follows so skills stay portable.
 
 ## The Rule
 
@@ -10,6 +10,7 @@ When a skill needs to render an image, resolve the backend in this order:
 2. **Saved preference** — if the skill's `EXTEND.md` sets `preferred_image_backend` to a backend available right now, use it.
 3. **Auto-select** (when the preference is `auto`, unset, or the pinned backend isn't available):
    - **Codex (`imagegen`)** — first, inspect your available-skills / tool inventory. If a skill named `imagegen` is listed, you are running inside Codex and MUST use it: invoke via the `Skill` tool with `skill: "imagegen"`, passing the saved prompt file's content (plus output path and aspect ratio per Codex `imagegen`'s own args). Codex `imagegen` is the official raster backend in that runtime and outranks any non-native skill (e.g., `baoyu-image-gen`) unless the user has explicitly pinned a different `preferred_image_backend`.
+   - **Cursor (`GenerateImage`)** — if the runtime exposes a native `GenerateImage` tool, you are running inside Cursor and it outranks any non-native skill the same way Codex `imagegen` does. Two hard caveats: (a) it has no aspect-ratio parameter — state the target aspect ratio / dimensions explicitly in the prompt text passed as `description`; (b) it does not accept an output directory — it saves to a tool-managed location, so after generation copy/move the file to the skill's expected output path (e.g., `outputs/.../NN-xxx.png`). Reference images go in `reference_image_paths`.
    - **Other runtime-native tools** — if the runtime exposes a different native image tool (e.g., Hermes `image_generate`), use it the same way.
    - Otherwise, if exactly one non-native backend is installed (e.g., `baoyu-image-gen`), use it.
    - Otherwise (multiple non-native backends with no runtime-native tool), ask the user once — batch with any other initial questions.
@@ -27,7 +28,7 @@ Each image-consuming skill's `EXTEND.md` carries a single `preferred_image_backe
 |---|---|
 | `auto` (default) | Apply the auto-select rule — runtime-native preferred, fall back to only installed backend, ask if multiple non-native. |
 | `ask` | Always confirm the backend on every run, even when a runtime-native tool exists. |
-| `<backend-id>` (e.g., `codex-imagegen`, `baoyu-image-gen`, `image_generate`) | Pin this backend when available; fall back to `auto` if it isn't. |
+| `<backend-id>` (e.g., `codex-imagegen`, `baoyu-image-gen`, `GenerateImage`, `image_generate`) | Pin this backend when available; fall back to `auto` if it isn't. |
 
 The field is **absent-equals-auto**: older `EXTEND.md` files without this field behave exactly as if `preferred_image_backend: auto` were set. No schema version bump is needed to introduce it.
 
@@ -41,7 +42,7 @@ Each `SKILL.md` that renders images includes **exactly one** `## Image Generatio
 
 Each skill's `references/config/preferences-schema.md` (and its `EXTEND.md` template in `first-time-setup.md`) lists `preferred_image_backend` alongside other preference fields. First-time setup does NOT ask the user about the backend — `auto` is set silently. Users who want to pin a specific backend edit `EXTEND.md` later, and each skill's `## Changing Preferences` section documents the common one-line edits.
 
-Concrete tool names (`imagegen`, `image_generate`, `baoyu-image-gen`) in this document and in SKILL.md are **examples** — agents in other runtimes apply the rule above and substitute the local equivalent. Skill-specific parameters for these backends are illustrative; runtimes without those knobs can omit them.
+Concrete tool names (`imagegen`, `GenerateImage`, `image_generate`, `baoyu-image-gen`) in this document and in SKILL.md are **examples** — agents in other runtimes apply the rule above and substitute the local equivalent. Skill-specific parameters for these backends are illustrative; runtimes without those knobs can omit them.
 
 ## Backend Skills Are Exempt