[0m
> build · openai/gpt-5.4
[0m
[0m# [0mTodos
[ ] Inspect workspace and identify existing files
[ ] Scaffold VS Code extension files and config
[ ] Implement markdown Mermaid block preview/edit webview flow
[ ] Add README install/test instructions
[ ] Write concise completion summary to COMPLETION.md
[0m
[0m✱ [0mGlob "**/*"[90m in . · 3 matches[0m
[0m
[0m# [0mTodos
[x] Inspect workspace and identify existing files
[ ] Scaffold VS Code extension files and config
[ ] Implement markdown Mermaid block preview/edit webview flow
[ ] Add README install/test instructions
[ ] Write concise completion summary to COMPLETION.md
[0m
[0m⚙ [0mapply_patch Success. Updated the following files:
A home/ubuntu/opencode-work/diagram-preview-tool-build/package.json
A home/ubuntu/opencode-work/diagram-preview-tool-build/tsconfig.json
A home/ubuntu/opencode-work/diagram-preview-tool-build/.vscodeignore
A home/ubuntu/opencode-work/diagram-preview-tool-build/src/extension.ts
A home/ubuntu/opencode-work/diagram-preview-tool-build/README.md
A home/ubuntu/opencode-work/diagram-preview-tool-build/COMPLETION.md
[0m
[0m$ [0mls
COMPLETION.md
README.md
SPEC.md
build-brief.md
build-output.txt
package.json
src
tsconfig.json
[0m
[0m# [0mTodos
[x] Inspect workspace and identify existing files
[x] Scaffold VS Code extension files and config
[ ] Implement markdown Mermaid block preview/edit webview flow
[ ] Add README install/test instructions
[ ] Write concise completion summary to COMPLETION.md
[0m
[0m$ [0mnpm install
added 2 packages, and audited 3 packages in 1s

found 0 vulnerabilities
[0m
[0m$ [0mnpm run build
> diagram-preview-tool@0.0.1 build
> tsc -p ./
[0m
[0m# [0mTodos
[x] Inspect workspace and identify existing files
[x] Scaffold VS Code extension files and config
[x] Implement markdown Mermaid block preview/edit webview flow
[x] Add README install/test instructions
[x] Write concise completion summary to COMPLETION.md
[0m
Built the VS Code extension MVP directly in this workspace and kept the Markdown Mermaid block as the only persisted source of truth.

- Added the extension scaffold and command wiring in `package.json`, with TypeScript build config in `tsconfig.json`
- Implemented the core flow in `src/extension.ts`: detect the Mermaid block under the cursor, open a preview-first webview, live-render Mermaid, and refresh from Markdown changes
- Added a minimal but usable webview editor/preview experience with wide-screen friendly layout and an explicit `Reveal Block in Markdown` action
- Wrote install/run instructions in `README.md`
- Wrote the requested completion note in `COMPLETION.md`

Verified:
- Ran `npm install`
- Ran `npm run build`
- TypeScript compilation completed successfully

Key files:
- `package.json`
- `src/extension.ts`
- `README.md`
- `COMPLETION.md`

A couple of implementation notes:
- The preview uses Mermaid from `jsdelivr` inside the VS Code webview for the smallest installable MVP
- V1 opens one Mermaid block at a time and tracks file edits so the preview stays synced if the Markdown source changes

Natural next steps if you want them:
1. Add VS Code packaging support with `vsce` so you can install a `.vsix`
2. Add block navigation when a file contains multiple Mermaid fences
3. Replace CDN Mermaid with a bundled local asset for fully offline use
