Adds an inline system prompt editor & toggle to DeepSeek chat. The prompt is injected as a system message before every new chat.
// ==UserScript==
// @name DeepSeek System Prompt
// @namespace http://tampermonkey.net/
// @version 1.2
// @description Adds an inline system prompt editor & toggle to DeepSeek chat. The prompt is injected as a system message before every new chat.
// @match https://chat.deepseek.com/*
// @grant GM_getValue
// @grant GM_setValue
// @grant GM_addStyle
// @grant unsafeWindow
// @run-at document-start
// @license MIT
// ==/UserScript==
(function () {
'use strict';
/* ── Storage keys ─────────────────────────────── */
const STORAGE_KEY = 'ds_system_prompt';
const ENABLED_KEY = 'ds_system_prompt_on';
let systemPrompt = GM_getValue(STORAGE_KEY, '');
let isEnabled = GM_getValue(ENABLED_KEY, true);
/* ── API patterns to intercept ────────────────── */
const API_PATTERNS = [
'/api/v0/chat/completion',
'/chat/completions',
'/v1/chat/completions',
];
/* ── Helpers ──────────────────────────────────── */
function log(...a) { console.log('[DS-SysPrompt]', ...a); }
/* ── Network interception ─────────────────────── */
const patched = new WeakSet();
function modifyBody(body, url) {
if (!body || !systemPrompt || !isEnabled) return body;
try {
let raw = typeof body === 'string' ? body : null;
if (!raw) return body;
const data = JSON.parse(raw);
if (Array.isArray(data.messages)) {
const hasSystem = data.messages.some(m => m.role === 'system');
if (!hasSystem) {
data.messages.unshift({ role: 'system', content: systemPrompt });
log('Injected system message into messages[]', url);
return JSON.stringify(data);
}
}
if (typeof data.prompt === 'string') {
data.prompt = `[SYSTEM INSTRUCTION]\n${systemPrompt}\n\n[USER MESSAGE]\n${data.prompt}`;
log('Injected system prompt into prompt field', url);
return JSON.stringify(data);
}
} catch (_) {}
return body;
}
function matchesAPI(url) {
return API_PATTERNS.some(p => String(url).includes(p));
}
function patchFetch() {
const w = unsafeWindow;
const orig = w.fetch;
if (patched.has(orig)) return;
w.fetch = async function (url, opts = {}) {
if (matchesAPI(url) && opts.body) {
const cloned = { ...opts };
if (cloned.body instanceof Blob) {
try {
const text = await cloned.body.text();
const mod = modifyBody(text, url);
if (mod !== text) cloned.body = new Blob([mod], { type: cloned.body.type });
} catch (_) {}
} else {
cloned.body = modifyBody(cloned.body, url);
}
return orig.call(this, url, cloned);
}
return orig.call(this, url, opts);
};
Object.keys(orig).forEach(k => { try { w.fetch[k] = orig[k]; } catch (_) {} });
patched.add(orig);
log('fetch patched');
}
function patchXHR() {
const XHR = unsafeWindow.XMLHttpRequest;
if (patched.has(XHR.prototype)) return;
const origOpen = XHR.prototype.open;
const origSend = XHR.prototype.send;
XHR.prototype.open = function (method, url, ...rest) {
this._dsUrl = url;
return origOpen.call(this, method, url, ...rest);
};
XHR.prototype.send = function (body) {
if (this._dsUrl && matchesAPI(this._dsUrl)) {
arguments[0] = modifyBody(body, this._dsUrl);
}
return origSend.apply(this, arguments);
};
patched.add(XHR.prototype);
log('XHR patched');
}
function patchWS() {
const OrigWS = unsafeWindow.WebSocket;
if (patched.has(OrigWS)) return;
unsafeWindow.WebSocket = function (url, protocols) {
const ws = new OrigWS(url, protocols);
const origSend = ws.send;
ws.send = function (data) {
if (systemPrompt && isEnabled && typeof data === 'string') {
try {
const obj = JSON.parse(data);
if (typeof obj.prompt === 'string') {
obj.prompt = `[SYSTEM INSTRUCTION]\n${systemPrompt}\n\n[USER MESSAGE]\n${obj.prompt}`;
data = JSON.stringify(obj);
}
} catch (_) {}
}
return origSend.call(this, data);
};
return ws;
};
Object.keys(OrigWS).forEach(k => { try { unsafeWindow.WebSocket[k] = OrigWS[k]; } catch (_) {} });
patched.add(OrigWS);
log('WebSocket patched');
}
function applyPatches() { patchFetch(); patchXHR(); patchWS(); }
applyPatches();
let n = 0;
const iv = setInterval(() => { applyPatches(); if (++n > 15) clearInterval(iv); }, 400);
/* ── Styles ───────────────────────────────────── */
// Minimal CSS — panel positioning is done via JS inline styles to avoid
// the CSS `position: fixed` bug caused by ancestor transforms on the page.
GM_addStyle(`
#ds-sp-toggle {
cursor: pointer !important;
}
`);
/* ── UI state ─────────────────────────────────── */
let panelEl = null;
let toggleBtn = null;
let textareaEl = null;
let charCountEl = null;
let switchTrack = null;
let toastEl = null;
let injected = false;
/* ── Toast ────────────────────────────────────── */
function showToast(msg) {
if (!toastEl) {
toastEl = document.createElement('div');
Object.assign(toastEl.style, {
position: 'fixed', bottom: '28px', left: '50%',
transform: 'translateX(-50%) translateY(8px)',
background: '#1a1a2e', color: '#fff',
padding: '8px 20px', borderRadius: '10px',
fontSize: '13px', fontFamily: '-apple-system, BlinkMacSystemFont, sans-serif',
opacity: '0', pointerEvents: 'none',
transition: 'opacity .25s, transform .25s',
zIndex: '2147483647', boxShadow: '0 4px 14px rgba(0,0,0,.2)',
});
document.documentElement.appendChild(toastEl);
}
toastEl.textContent = msg;
toastEl.style.opacity = '1';
toastEl.style.transform = 'translateX(-50%) translateY(0)';
clearTimeout(toastEl._t);
toastEl._t = setTimeout(() => {
toastEl.style.opacity = '0';
toastEl.style.transform = 'translateX(-50%) translateY(8px)';
}, 2200);
}
/* ── State sync ───────────────────────────────── */
function syncToggleState() {
if (!toggleBtn) return;
toggleBtn.classList.toggle('ds-toggle-button--selected', isEnabled && !!systemPrompt);
}
function updateCharCount() {
if (charCountEl && textareaEl) {
charCountEl.textContent = textareaEl.value.length + ' chars';
}
}
/* ── Panel open/close ─────────────────────────── */
function openPanel() {
if (!panelEl) return;
textareaEl.value = systemPrompt;
updateCharCount();
switchTrack.classList.toggle('ds-sp-on', isEnabled);
panelEl.style.display = 'flex';
// Animate in next frame
requestAnimationFrame(() => {
panelEl.style.opacity = '1';
panelEl.style.transform = 'translateY(0)';
});
setTimeout(() => textareaEl.focus(), 80);
}
function closePanel() {
if (!panelEl) return;
panelEl.style.opacity = '0';
panelEl.style.transform = 'translateY(8px)';
setTimeout(() => { panelEl.style.display = 'none'; }, 200);
}
function save() {
systemPrompt = textareaEl.value.trim();
GM_setValue(STORAGE_KEY, systemPrompt);
GM_setValue(ENABLED_KEY, isEnabled);
syncToggleState();
closePanel();
showToast(systemPrompt ? '✓ System prompt saved' : '✓ System prompt cleared');
log('Saved. Enabled:', isEnabled, 'Prompt length:', systemPrompt.length);
}
/* ── Build panel with inline styles ───────────── */
function createPanel() {
const panel = document.createElement('div');
panel.id = 'ds-sp-panel';
Object.assign(panel.style, {
position: 'fixed',
zIndex: '2147483647',
left: '50%',
transform: 'translateX(-50%) translateY(8px)',
width: '520px',
maxWidth: 'calc(100vw - 40px)',
background: '#fff',
border: '1px solid #e4e4e7',
borderRadius: '16px',
boxShadow: '0 12px 40px rgba(0,0,0,.12), 0 2px 8px rgba(0,0,0,.06)',
padding: '0',
display: 'none',
opacity: '0',
flexDirection: 'column',
fontFamily: "-apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif",
transition: 'opacity .2s ease, transform .2s ease',
overflow: 'visible',
boxSizing: 'border-box',
});
// --- Header ---
const header = document.createElement('div');
Object.assign(header.style, {
display: 'flex', alignItems: 'center', justifyContent: 'space-between',
padding: '14px 18px 10px', borderBottom: '1px solid #eee',
});
const title = document.createElement('div');
Object.assign(title.style, {
fontSize: '14px', fontWeight: '600', color: '#1a1a2e',
display: 'flex', alignItems: 'center', gap: '6px',
});
title.innerHTML = `<svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M12 20h9"/><path d="M16.5 3.5a2.121 2.121 0 0 1 3 3L7 19l-4 1 1-4L16.5 3.5z"/></svg> System Prompt`;
const closeBtn = document.createElement('button');
Object.assign(closeBtn.style, {
width: '28px', height: '28px', border: 'none', background: 'transparent',
color: '#999', fontSize: '18px', cursor: 'pointer', borderRadius: '6px',
display: 'flex', alignItems: 'center', justifyContent: 'center',
});
closeBtn.textContent = '×';
closeBtn.addEventListener('click', closePanel);
closeBtn.addEventListener('mouseenter', () => { closeBtn.style.background = 'rgba(0,0,0,.06)'; });
closeBtn.addEventListener('mouseleave', () => { closeBtn.style.background = 'transparent'; });
header.appendChild(title);
header.appendChild(closeBtn);
// --- Body ---
const body = document.createElement('div');
Object.assign(body.style, { padding: '12px 18px 8px' });
const ta = document.createElement('textarea');
ta.placeholder = 'Enter a system-level instruction that will be sent with every new chat…\n\nExample: You are a senior software engineer. Always provide code examples and explain your reasoning step by step.';
ta.spellcheck = false;
Object.assign(ta.style, {
width: '100%', minHeight: '120px', maxHeight: '260px', resize: 'vertical',
border: '1.5px solid #e4e4e7', borderRadius: '10px', padding: '12px 14px',
fontSize: '13.5px', lineHeight: '1.55',
fontFamily: "'SF Mono', 'Fira Code', Consolas, monospace",
color: '#333', background: '#fafafa', outline: 'none',
transition: 'border-color .2s', boxSizing: 'border-box',
display: 'block',
});
ta.addEventListener('focus', () => { ta.style.borderColor = '#4772f6'; ta.style.background = '#fff'; });
ta.addEventListener('blur', () => { ta.style.borderColor = '#e4e4e7'; ta.style.background = '#fafafa'; });
ta.addEventListener('input', updateCharCount);
ta.addEventListener('keydown', (e) => {
if (e.key === 'Enter' && (e.ctrlKey || e.metaKey)) { e.preventDefault(); save(); }
if (e.key === 'Escape') closePanel();
});
const charCount = document.createElement('div');
Object.assign(charCount.style, {
textAlign: 'right', fontSize: '11px', color: '#aaa', marginTop: '4px', paddingRight: '2px',
});
charCount.textContent = '0 chars';
body.appendChild(ta);
body.appendChild(charCount);
// --- Footer ---
const footer = document.createElement('div');
Object.assign(footer.style, {
display: 'flex', alignItems: 'center', justifyContent: 'space-between',
padding: '10px 18px 14px', borderTop: '1px solid #eee', gap: '10px',
});
const leftGroup = document.createElement('div');
Object.assign(leftGroup.style, { display: 'flex', alignItems: 'center', gap: '12px' });
// Toggle switch
const switchLabel = document.createElement('label');
Object.assign(switchLabel.style, {
display: 'flex', alignItems: 'center', gap: '8px',
fontSize: '13px', color: '#666', cursor: 'pointer', userSelect: 'none',
});
const track = document.createElement('div');
Object.assign(track.style, {
width: '36px', height: '20px', borderRadius: '12px',
background: isEnabled ? '#4772f6' : '#ccc',
position: 'relative', transition: 'background .2s', flexShrink: '0',
});
const thumb = document.createElement('div');
Object.assign(thumb.style, {
width: '16px', height: '16px', borderRadius: '50%', background: '#fff',
position: 'absolute', top: '2px', left: isEnabled ? '18px' : '2px',
transition: 'left .2s', boxShadow: '0 1px 3px rgba(0,0,0,.18)',
});
track.appendChild(thumb);
// Add ds-sp-on class handling via JS
track._update = function (on) {
track.style.background = on ? '#4772f6' : '#ccc';
thumb.style.left = on ? '18px' : '2px';
};
const enabledText = document.createElement('span');
enabledText.textContent = 'Enabled';
switchLabel.appendChild(track);
switchLabel.appendChild(enabledText);
switchLabel.addEventListener('click', () => {
isEnabled = !isEnabled;
track._update(isEnabled);
});
// Clear button
const clearBtn = document.createElement('button');
clearBtn.textContent = 'Clear';
Object.assign(clearBtn.style, {
background: 'none', border: 'none', color: '#e05555',
fontSize: '12px', cursor: 'pointer', padding: '4px 8px', borderRadius: '6px',
});
clearBtn.addEventListener('click', () => { ta.value = ''; updateCharCount(); });
clearBtn.addEventListener('mouseenter', () => { clearBtn.style.background = 'rgba(224,85,85,.08)'; });
clearBtn.addEventListener('mouseleave', () => { clearBtn.style.background = 'none'; });
leftGroup.appendChild(switchLabel);
leftGroup.appendChild(clearBtn);
// Save button
const saveBtn = document.createElement('button');
saveBtn.textContent = 'Save';
Object.assign(saveBtn.style, {
padding: '6px 20px', borderRadius: '8px', border: 'none',
background: '#4772f6', color: '#fff', fontSize: '13px',
fontWeight: '500', cursor: 'pointer',
});
saveBtn.addEventListener('click', save);
saveBtn.addEventListener('mouseenter', () => { saveBtn.style.background = '#3b62e0'; });
saveBtn.addEventListener('mouseleave', () => { saveBtn.style.background = '#4772f6'; });
footer.appendChild(leftGroup);
footer.appendChild(saveBtn);
// --- Assemble ---
panel.appendChild(header);
panel.appendChild(body);
panel.appendChild(footer);
// Store references
textareaEl = ta;
charCountEl = charCount;
switchTrack = track; // we use track._update() instead of class toggling
return panel;
}
/* override switchTrack class toggle to use JS */
const origOpenPanel = openPanel;
/* ── Position panel above the input area ───────── */
function positionPanel() {
if (!panelEl || !toggleBtn) return;
const btnRect = toggleBtn.getBoundingClientRect();
// Place panel so its bottom is just above the button row, centered horizontally
const panelHeight = panelEl.offsetHeight || 300;
const top = btnRect.top - panelHeight - 12;
panelEl.style.top = Math.max(10, top) + 'px';
}
/* ── Build UI ─────────────────────────────────── */
function buildUI() {
if (injected) return;
if (document.getElementById('ds-sp-toggle')) { injected = true; return; }
const toggleButtons = document.querySelectorAll('.ds-toggle-button');
if (!toggleButtons.length) return;
const lastToggle = toggleButtons[toggleButtons.length - 1];
const toolbar = lastToggle.parentElement;
if (!toolbar) return;
/* ── Toggle button ── */
toggleBtn = document.createElement('div');
toggleBtn.id = 'ds-sp-toggle';
toggleBtn.setAttribute('role', 'button');
toggleBtn.className = 'ds-atom-button ds-toggle-button ds-toggle-button--md';
toggleBtn.innerHTML = '<div><svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M12 20h9"/><path d="M16.5 3.5a2.121 2.121 0 0 1 3 3L7 19l-4 1 1-4L16.5 3.5z"/></svg></div><span><span>System</span></span>';
toggleBtn.title = 'Click to edit system prompt';
toggleBtn.addEventListener('click', (e) => {
e.preventDefault();
e.stopPropagation();
const isOpen = panelEl && panelEl.style.display === 'flex';
if (isOpen) closePanel();
else { openPanel(); positionPanel(); }
});
syncToggleState();
if (lastToggle.nextSibling) {
toolbar.insertBefore(toggleBtn, lastToggle.nextSibling);
} else {
toolbar.appendChild(toggleBtn);
}
/* ── Panel ── */
panelEl = createPanel();
// Append to <html> to escape any transform containers
document.documentElement.appendChild(panelEl);
/* click-outside to close */
document.addEventListener('mousedown', (e) => {
if (panelEl.style.display === 'flex' &&
!panelEl.contains(e.target) &&
e.target !== toggleBtn &&
!toggleBtn.contains(e.target)) {
closePanel();
}
});
// Re-center on resize
window.addEventListener('resize', () => {
if (panelEl.style.display === 'flex') positionPanel();
});
injected = true;
log('UI injected (v1.1)');
}
/* ── Override openPanel to use JS-based switch ── */
const _origOpen = openPanel;
openPanel = function () {
if (!panelEl) return;
textareaEl.value = systemPrompt;
updateCharCount();
switchTrack._update(isEnabled);
panelEl.style.display = 'flex';
requestAnimationFrame(() => {
panelEl.style.opacity = '1';
panelEl.style.transform = 'translateX(-50%) translateY(0)';
positionPanel();
});
setTimeout(() => textareaEl.focus(), 80);
};
/* ── Observer ─────────────────────────────────── */
function tryInject() {
if (document.getElementById('ds-sp-toggle')) { injected = true; syncToggleState(); return; }
injected = false;
buildUI();
}
const mo = new MutationObserver(() => {
if (!document.getElementById('ds-sp-toggle')) injected = false;
if (!injected) buildUI();
});
function start() {
tryInject();
if (document.body) mo.observe(document.body, { childList: true, subtree: true });
}
if (document.readyState === 'loading') {
document.addEventListener('DOMContentLoaded', start);
} else {
start();
}
let lastUrl = location.href;
new MutationObserver(() => {
if (location.href !== lastUrl) {
lastUrl = location.href;
applyPatches();
setTimeout(tryInject, 300);
}
}).observe(document, { subtree: true, childList: true });
})();