dsh-client-math-input

A visual equation editor for the DeepSeek Harness web composer. Adds an ƒx button next to the message box; it opens a MathLive math field, and Insert writes the field's LaTeX into your draft as a $$...$$ block — so the model reads canonical LaTeX instead of you hand-typing \frac{...}{...} syntax.

Install

dsh plugin --profile web add @louisdevzz/dsh-client-math-input

Restart dsh web. The ƒx button appears in the composer's tool row, next to the attach/plan controls.

Without the dsh plugin bundle machinery: pnpm link this package into $DSH_HOME/profiles/<name> and add an insert row for @louisdevzz/dsh-client-math-input to that profile's own cordis.patch.yml (the row shape is in this repo's cordis.patch.yml).

What you get

• ƒx button in the composer tool row — registered into ui-conversation's conversation.input.left seat, beside the existing chrome (access mode, plan, attach), not replacing it
• MathLive editor popup — the full interactive <math-field> widget (built-in LaTeX commands, virtual keyboard, keyboard shortcuts), floating above the composer the same way the slash-command menu does
• Word paste (best-effort) — pasting a Word equation recovers its LaTeX when Word's clipboard includes a MathML fallback (see below); everything else pastes into the field exactly as MathLive already handles it
• Zero session-log/model changes — Insert just writes plain $$...$$ text into the draft; the model sees ordinary message text, nothing new to learn on the wire

Pasting from Word

MathLive's own paste handler only reads application/json+mathlive, application/json (with a compute engine loaded — not enabled here), application/x-latex, and text/plain off the clipboard. A Word equation is none of those — Word's clipboard carries it as OMML/an image, with an HTML fallback for other apps — so pasting a Word equation directly into MathLive normally does nothing.

Word (since roughly 2018) additionally embeds a real <math> MathML island in that HTML fallback. This plugin intercepts paste in the capture phase, checks the clipboard's text/html payload for a <math> element, and if found converts it to LaTeX with mathml-to-latex before MathLive's own handler ever sees the event. If no MathML is present (older Word, or an equation copied as a plain image), the event is left alone and MathLive's normal paste behavior runs exactly as before.

Not verified against a live Word paste (no Word/browser in the environment this was built in) — only against a hand-built HTML fragment shaped like Word's documented MathML fallback (src/client/word-paste.test.ts, pnpm test). If it doesn't work with your Word version: open devtools, run document.addEventListener('paste', e => console.log(e.clipboardData.getData('text/html')), true), paste the equation, and check whether the logged HTML contains a <math> tag — if not, there's nothing this plugin can recover from that paste (would need a full OMML parser, not attempted here).

Known limitations

• No outside-click dismissal on the popup (closes via ✕, Cancel, Insert, or Escape) — not needed to prove the LaTeX round-trip, so deliberately deferred
• Always inserts display-mode ($$...$$); no inline-math toggle
• Word-paste recovery only handles the case where Word's clipboard includes a MathML fallback; OMML-only paste (older Word, or Word configured without the MathML fallback) still silently does nothing
• lib/client.js is ~1.5MB (mathlive + mathml-to-latex, both bundled since neither is a shared platform module) — fine for a manually-installed personal plugin, not optimized for load time
• Types for @deepseek-ai/dsh-client-* are pinned to ^0.1.1-rc.2 (the next dist-tag) — the npm latest tag for these packages currently points at a much older, incompletely-published 0.0.1-rc.1 line; do not loosen these version pins to an unpinned range

Build from source

pnpm install
pnpm build       # tsc declarations (lib/types) + tsdown browser/node bundles (lib/)
pnpm typecheck
pnpm test        # word-paste MathML recovery, node:test + jsdom

src/index.ts is the host-side plugin half (a no-op; this is a pure browser UI plugin). src/client/index.ts is the browser half: it registers the ƒx button into conversation.input.left and the editor popup into conversation.input.overlay, sharing one open/closed store between them.

tsdown.config.ts builds on tsdown.client.ts (adapted from DSH's internal packages/client/tsdown.client.ts preset): the browser bundle is a closure-factory artifact (window.__ModuleLoader__.load({id, factory})) that resolves react, @deepseek-ai/cordis, @deepseek-ai/dsh-client-ui-slots, @deepseek-ai/dsh-client-ui-primitives, and @deepseek-ai/dsh-client-runtime/client through the running dsh app's own module table instead of bundling them — those must stay the same singleton instances as the rest of the app. mathlive and mathml-to-latex are genuine dependencies and get bundled directly into lib/client.js.

One non-obvious fix baked into tsdown.config.ts: mathlive's package.json exports a conditional entry keyed on browser/node/default, and rolldown (running under Node) resolves it via the node condition — landing on mathlive-ssr.min.mjs, a headless rendering build with no <math-field> custom element at all. The config resolves mathlive.min.mjs explicitly instead of trusting the exports map.

This is an out-of-tree plugin, independent of the deepseek-harness monorepo — see docs/user/develop/basic/publish.md in that repo for the profile/bundle plugin model this package follows.

License

MIT