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Browser AI Agents (WebMCP)

The MCP server connects Hisaabo to AI assistants that run outside the browser — Claude Desktop, OpenClaw, a cron job on your server. WebMCP does the opposite: it lets the AI agent that is already built into your browser use Hisaabo directly, with no install, no token, and no config file.

WebMCP is a draft standard from the W3C Web Machine Learning Community Group. A web page calls document.modelContext.registerTool({...}) to describe what it can do, and the browser’s agent — Gemini in Chrome, Copilot in Edge — discovers those tools and calls them while you are on the page. Once you are signed in to Hisaabo and have picked a business, the web app registers about 20 tools, named exactly the same as their MCP server counterparts. You then talk to the browser’s agent the way you would talk to Claude, and it operates your books in the tab you already have open.

The important part is where the work happens. The tools run inside your logged-in tab, through your existing session cookie and x-business-id header. There is no separate API key to mint, nothing to paste into a config file, and nothing for Hisaabo to bill you for — the agent runs on your own browser AI subscription, so a self-hosted instance costs exactly as much to run whether you use this or not.

How to Enable It

Section titled “How to Enable It”

1. Turn on WebMCP in your browser

Section titled “1. Turn on WebMCP in your browser”

As of September 2026 the API is still shipping behind a trial.

Browser Status How to turn it on
Chrome 149+ Origin trial (through roughly Chrome 156) Works automatically on an origin with a valid trial token. For local testing: chrome://flags/#enable-webmcp-testing (older builds call it #enable-webmcp)
Edge 150+ Origin trial Works automatically on an origin with a valid trial token
Firefox / Safari Evaluating the spec Not available yet
Brave Experimental, via Leo Enable in Leo’s settings

If your browser does not expose the API, Hisaabo’s Settings page says so and nothing else changes — the app works exactly as before.

2. Register an origin trial token (production)

Section titled “2. Register an origin trial token (production)”

Origin trial tokens are issued per origin. If you self-host Hisaabo, register your own for the origin you serve the app from:

  1. Go to developer.chrome.com/origintrials and register WebMCP for your origin (for example https://app.yourdomain.com).

  2. Put the token in your web build environment:

    Terminal window
    VITE_WEBMCP_ORIGIN_TRIAL_TOKEN=Az4f...

  3. Rebuild the web app. The build injects <meta http-equiv="origin-trial" content="..."> into index.html. When the variable is unset, no tag is emitted.

You do not need a token if you are testing with the Chrome flag, and you will not need one once the API ships in stable.

3. Switch it on in Hisaabo

Section titled “3. Switch it on in Hisaabo”

Open Settings → Account → Browser AI agents and turn on Allow this browser’s AI agent to use Hisaabo. It is off by default (opt-in) and stored per browser, so enabling or disabling it on your office machine does not affect your laptop.

What the Agent Can Do

Section titled “What the Agent Can Do”

The web app registers the tools below. They are the same names, and the same behaviour, as the corresponding MCP server tools — a request that works in Claude Desktop reads the same way to Gemini in Chrome.

Tool Type Asks for confirmation What it does
hisaabo_context Read No Who you are, which business is selected, your role
app_navigate Read No Opens a page in the app (invoices, parties, reports, …)
dashboard_summary Read No Sales, cash position, receivables for a period
invoice_list Read No Invoices, filterable by status, party and date
invoice_get Read No One invoice with its line items and tax breakdown
invoice_create Write Yes Creates an invoice
invoice_update_status Write Yes Moves an invoice between draft, sent, paid, cancelled
party_list Read No Customers and suppliers, with outstanding balances
party_get Read No One party with contact details and balance
party_create Write Yes Creates a customer or supplier
item_list Read No Catalogue items with stock levels
item_get Read No One item with units, price and HSN
item_create Write Yes Creates a catalogue item
payment_list Read No Recorded payments
payment_unpaid_invoices Read No Invoices still awaiting payment
payment_create Write Yes Records a payment against an invoice
expense_list Read No Recorded expenses
expense_categories Read No Your expense categories
expense_create Write Yes Records an expense

Read tools are annotated untrustedContentHint, which tells the agent that the returned text is your business data and not instructions to follow. Write tools are annotated consequentialHint, which is what makes the browser stop and ask you before running them.

Safety and Permissions

Section titled “Safety and Permissions”

The design goal is that an agent can do nothing through WebMCP that you could not do yourself by clicking, and nothing at all that you did not approve.

  • Your session, not a new one. Tools run in your logged-in tab, over the same cookie session and x-business-id header the dashboard uses. There is no separate key to leak, and closing the tab or signing out ends the agent’s access immediately.
  • Your role applies. If your role cannot create invoices in the UI, invoice_create fails for the agent too. Permission checks live on the server and are identical for both paths. See Team & Roles.
  • Same validation. Inputs go through the same schemas as the dashboard. A GSTIN that the form would reject is rejected here too.
  • Everything is in the audit trail. Every write is logged exactly as a manual one is, visible under Settings → Account → Activity. You can always see what the agent did.
  • No delete tools. Nothing destructive is exposed. The agent cannot delete an invoice, a party, an item, a payment or an expense — deletions stay a deliberate human action in the UI.
  • Off until you turn it on. Browser AI agent access is opt-in: no tools are registered until you enable Settings → Account → Browser AI agents in that browser.
  • Writes ask first, inside Hisaabo. Every tool that changes data is marked consequential, and Hisaabo itself shows a confirmation dialog describing what is about to happen. Nothing is written until you approve it there.
  • Prompt injection. Anything an agent reads can try to instruct it — a party name, an invoice note, a product description typed by someone else. Read results carry untrustedContentHint so the agent treats them as data, but the confirmation prompt on every write is the real backstop. Read what you are approving, especially for amounts and party names.
  • Turn it off. Settings → Account → Browser AI agents. The tools are unregistered immediately, per browser. The setting is stored per browser.

Which Agents Work Today

Section titled “Which Agents Work Today”
Agent Status
Gemini in Chrome Works — Chrome 149+ with the origin trial or the testing flag
Copilot in Edge Works — Edge 150+ with the origin trial
ChatGPT Desktop Consumes WebMCP tools from the browser
Claude in Chrome Does not consume WebMCP today (claude-code#30645, closed as not planned)

If you use Claude, nothing changes: keep using the MCP server with @hisaabo/mcp. It covers considerably more ground than the browser tools — well over a hundred tools including GST reports, banking, shipments and bulk import — and it works from Claude Desktop without a browser tab open at all.

Example Prompts

Section titled “Example Prompts”

With Hisaabo open and the browser agent enabled, these all work in one turn.

You: "Create an invoice for Montu Arora — 7.3 kg spinach at Rs. 65/kg"


Gemini: [calls party_list to resolve "Montu Arora", item_list to resolve "spinach"]
        [calls invoice_create — Chrome asks you to confirm before it runs]
        "Invoice BB-12948 created for Montu Arora — Rs. 474.50
         (7.3 kg x Rs. 65, exempt from GST as fresh vegetables)."
You: "Which customers owe me more than Rs. 10,000, oldest first?"


Gemini: [calls party_list with an outstanding balance filter]
        "Three: Vinod & Sons Rs. 11,400 (63 days), Sharma Traders
         Rs. 34,200 (47 days), Gupta Enterprises Rs. 18,750 (12 days).
         Want me to open Vinod & Sons' ledger?"
You: "Record the Rs. 15,000 UPI payment Sharma Traders sent this morning"


Gemini: [calls payment_unpaid_invoices for Sharma Traders]
        [calls payment_create — Chrome asks you to confirm before it runs]
        "Recorded Rs. 15,000 by UPI against BB-12903. That invoice is now
         fully paid; Sharma Traders' balance is Rs. 19,200."

Verify with Lighthouse

Section titled “Verify with Lighthouse”

Chrome’s Lighthouse has a Registered WebMCP tools audit under the Agentic browsing category. It is the quickest way to confirm that registration actually happened on your instance.

  1. Sign in to Hisaabo and select a business — tools are registered only after that.
  2. Open DevTools → Lighthouse, tick Agentic browsing, and run the audit on the page.
  3. The Registered WebMCP tools audit lists every tool the page registered, with its description and annotations.

If the audit reports no tools:

  • Check that the browser exposes the API at all — Settings → Account → Browser AI agents shows a note when it does not.
  • Check that the switch is on.
  • On a self-hosted instance, check that VITE_WEBMCP_ORIGIN_TRIAL_TOKEN was set at build time and matches the origin you are browsing, or enable chrome://flags/#enable-webmcp-testing for a quick local check.
  • Confirm you have selected a business — tools are not registered on the login or business-picker screens.
Section titled “Related Documentation”