Mermaid visual editor — a DeepSeek Harness (dsh) browser plugin.
A closable right-side panel that keeps the canvas and the Mermaid code in sync, and works directly with the agent.
Supports four diagram types: flowchart, sequenceDiagram, classDiagram, erDiagram.
The editor UI is the core — no MCP, no server, no VS Code extension; the plugin talks to dsh directly and touches zero dsh source code.
Features
Panel & layout
Toggle from the "Mermaid 编辑器" button at the bottom of the sidebar; in-page fullscreen (⧉) when the canvas needs room
Chat area yields + resizable width: a DOM layout controller appends an editor column to the shell grid — the chat auto-shrinks and is never occluded; drag the handle to resize (300–1200px, chat always keeps ≥400px), double-click to reset
Coexists with the dsh sidebar, the session details column, and dsh-web-ui's right panels (see "Coexistence protocol")
Responsive compact mode: below 420px the side panels hide, leaving only the canvas; "▥ 紧凑" toggles it manually
Independent dark mode (title-bar toggle, panel-scoped only)
Editor
Two-way sync between the visual canvas and the Mermaid code (canvas edits → code; code edits → canvas, committed on blur or Ctrl+Enter)
Diagram type switcher lives in the code section (flowchart / sequenceDiagram / classDiagram / erDiagram) with a confirm dialog, plus flowchart direction (TB/TD/BT/RL/LR) and connection mode (按方向/就近) selects and a copy-to-clipboard button
Node library drag-and-drop, connections, property panel, and dedicated editors for subgraphs / namespaces / entities / participants
Session isolation + multi-tabs: the panel follows the current session, tabs are stored per session; create / switch / close (confirm dialog) / rename on double-click / drag to reorder; each tab owns its canvas, code and viewport
Canvas and code persist to localStorage and restore on reload
Working with the agent (two-way Mermaid transfer)
mermaid2aichat-dsh · DSH Hub
AI → editor: registers the model tool mermaid_load (host-global layer, no preset change) — when the AI calls it, the diagram is auto-imported as a new tab and the panel opens to show it
Conversation → editor: scans the current session for ```mermaid blocks (AI messages, user messages, tool results); the sidebar badge shows unseen count, and "从对话导入" parses one into a new tab
Editor → conversation: "发送到对话" sends the active tab's code into the current session
Input-box reference: type / and the "mermaid" group lists the current session's tabs — pick one to insert its code block into the draft
Install
Option 1: npm (recommended)
dsh plugin --profile web add mermaid2aichat-dsh
Option 2: GitHub
dsh plugin --profile web add github:supergameboy/mermaid2aichat-dsh
Option 3: local directory (development)
dsh plugin --profile web add
lib/ build artifacts are committed, so git/npm installs work without a build step.
If pnpm blocks the build, allow the package in $DSH_HOME/profiles/web/pnpm-workspace.yaml
(allowBuilds) or use option 1.
After installing, restart dsh web (the mermaid_load tool registers at host startup), then refresh the page — the "Mermaid 编辑器" button appears at the bottom of the sidebar.
Recommended setup: working with archify & dsh-web-ui
Positioning
The value of mermaid2aichat-dsh is not "one more diagram tool" — it turns diagrams into an editable loop that feeds the agent:
AI analyzes / draws ──mermaid_load──▶ editor (editable) ──send to chat──▶ AI continues
user draws / edits ──editor──▶ Mermaid code ──send to chat──▶ AI analyzes / implements from the diagram
One-shot generators such as archify own the "analysis + polished HTML artifact" end; this plugin owns the "Mermaid workbench + two-way agent feed" end. The two complement each other without overlap.
Recommended installs
# this plugin (npm)
dsh plugin --profile web add mermaid2aichat-dsh
# dsh-web-ui family (right-side file tree / preview / task board, coexists on the same grid)
dsh plugin --profile web add @linxin666/dsh-web-ui-all
# archify: an agent skill (Claude Code / npx skills — see its README)
npx skills add tt-a1i/archify -g
How to work with them
Need a diagram you will keep editing and feed back to the agent (flowchart / sequenceDiagram / classDiagram / erDiagram)? Ask the agent to call mermaid_load into this editor, tweak it, then "发送到对话".
Need a one-shot polished artifact (architecture / data-flow / lifecycle, for docs / PRs / READMEs)? Ask the agent to generate a self-contained HTML with archify.
Both can coexist in the same session: dsh-web-ui's right panels and this plugin's editor column share the shell grid via the coexistence protocol.
Related projects
archify — agent skill: natural language to beautiful, self-contained HTML technical diagrams
dsh-web-ui — a family of dsh plugins (right-side file tree / preview, task board, etc.)
Working with the agent
Tell the agent:
Draw the flow of XXX as a flowchart and send it to the editor.
The agent calls mermaid_load, and the diagram appears in a new editor tab (the panel opens automatically). Adjust it in the editor and click "发送到对话" to send the updated code back; or type / in the input box to reference any tab's code block.
Architecture
One npm package plays three roles:
bundle (patch layer): dsh.bundle.patch → cordis.patch.yml registers the plugin as a dsh.client row;
host plugin (Node side): registers the model tool mermaid_load (global layer, visible to every session's agent);
client plugin (browser side): registers the launcher (sidebar.footer.action), the panel entry (shell.overlay), the input trigger (inputTriggers) and the DOM layout controller (client/layout.ts).
src/
index.ts host half (registers the mermaid_load tool)
client/ dsh plugin (state, panel, launcher, trigger, block scan, layout controller)
editor/ editor UI (canvas, node library, property panel, code editor)
serializer/ parser/serializer (jison parsers + serializers for the 4 types)
cordis.patch.yml bundle patch layer
lib/ build artifacts (committed; installs work out of the box)
The editor and serializer are bundled into lib/client.js (@xyflow/react, dagre-cluster-fix, js-yaml inlined; react and friends come from the dsh shell's module table).
Layout & coexistence protocol (no dsh changes needed)
The editor column is a grid track the layout controller appends at the DOM level: it mirrors the shell's inline grid-template-columns (2/3-track tolerant) and appends its own track, fully decoupled from the sidebar, chat and details column — no ctx.layout dependency, no slot shadowing, no host-version requirement.
dsh-web-ui (aionui-panel) uses the same technique for its file-tree/preview panels. When their columns are detected, the controller switches to a cooperative protocol: it writes 6 tracks (shell 3 + editor + their preview + their file tree), keeps the editor column before theirs, re-appends on their 5-track writes in the same frame, nudges with a bare shell 3-track write to converge after their HMR/late attach, and carries a write-burst guard so observer cascades can never freeze the page. Both panels show side by side.
Development
pnpm install # install dependencies
pnpm run build # builds lib/index.js (host) + lib/client.js (browser)
pnpm run typecheck
pnpm run watch # tsdown watch rebuild
After changing source, re-run pnpm run build; host-side changes (tool registration) need a dsh web restart, browser-side changes only a page refresh.
Known limitations
Only flowchart / sequenceDiagram / classDiagram / erDiagram are supported; parsing other types reports "unsupported"
"从对话导入" scans only the loaded message window of the current session; older pages need scrolling into view first
The client bundle is large (React Flow and all editor deps inlined); it is fetched on first panel open
The / input-trigger replaces the draft with the code block (setDraft semantics) and cannot append to existing draft text
Editor column width persists only on drag-end, double-click reset and window resize; sidebar/details toggles affect the current display width only, never the preference (matches dsh's own layout-preference semantics)
Acknowledgments
The DOM layout controller (mirroring the shell's grid, appending its own column track, and drawing custom drag handles) is inspired by the aionui-panel package in dsh-web-ui. Thanks to its author for sharing the approach — this plugin's coexistence protocol is built around that behavior so both can run side by side in the same GUI.
