Two pluggable surfaces were mentioned in the interfaces map without a
real authoring guide behind them:
1. **Image-gen backends** — only had 'See bundled examples' pointers.
Now a full developer-guide/image-gen-provider-plugin.md (270 lines)
mirroring the memory/context/model provider docs:
- How discovery works, directory structure, plugin.yaml
- ImageGenProvider ABC with every overridable method
(name, display_name, is_available, list_models, default_model,
get_setup_schema, generate)
- Full authoring walkthrough with a working MyBackendImageGenProvider
- Response-format reference (success_response / error_response)
- Handling b64 vs URL output (save_b64_image helper)
- User overrides at ~/.hermes/plugins/image_gen/<name>/
- Testing recipe + pip distribution
- Reference examples (openai, openai-codex, xai)
2. **Skill taps** — features/skills.md mentioned the CLI commands but
never explained the repo contract for publishing a tap. Added
'Publishing a custom skill tap' section under Skills Hub covering:
- Repo layout (skills/<name>/SKILL.md by default)
- Minimal working example
- Non-default path configuration (taps.json)
- Installing individual skills without subscribing
- Trust-level handling
- Full tap management CLI + in-session /skills tap commands
Wired into:
- website/sidebars.ts: image-gen-provider-plugin added to Extending group
- website/docs/user-guide/features/plugins.md: pluggable interfaces
table + 'What plugins can do' table now link to the real guides
instead of 'See bundled examples'
- website/docs/guides/build-a-hermes-plugin.md: top info map and
inline sub-sections updated, 'Full guide:' line added to
image-gen block, tap section mentions publishing
Verified: docusaurus build SUCCESS, new page renders at
/docs/developer-guide/image-gen-provider-plugin, anchor
#publishing-a-custom-skill-tap resolves from plugins.md +
build-a-hermes-plugin.md. Pre-existing zh-Hans broken links unchanged.
