# Hermes Call Ledger: Hermes Agent plugin

> Per-call cost ledger for Hermes Desktop: every model call Hermes makes is recorded from the observer hooks (provider, model, tokens, duration, outcome) and paired with the charge the billing provider actually took.

Canonical: https://hermeswatcher.com/plugins/hermes-call-ledger  
Tier: Community  
Official page (Nous Research): https://hermes-agent.nousresearch.com/docs/plugins/hermes-call-ledger  
Last updated in catalog: 2026-10-13

Per-call cost ledger for Hermes Desktop: every model call Hermes makes is recorded from the observer hooks (provider, model, tokens, duration, outcome) and paired with the charge the billing provider actually took; works with no billing account, priced by Hermes' own estimate where the price book knows the model. English or Vietnamese; dong or dollars.

## Good to know before installing

Three observer hooks (post_api_request, post_auxiliary_call, api_request_error) record per-call metadata from every profile in the install (session id, platform, task, provider, model, token counts, duration, finish reason, context length; never prompt, response or tool-argument text) into one shared SQLite ledger at <install root>/plugin-data/call-ledger/calls.sqlite, and import this plugin's own older per-profile ledgers into it once. It caches the vilao.ai model list there and the USD-to-VND rate under the active profile's plugin-data/call-ledger. Network is GET-only: vilao.ai (wallet balance, per-request usage, consumer keys) with VILAO_PAT read through Hermes's secret scope (vilao issues one full-scope token per account, including wallet writes; this plugin only reads), the public vilao.ai model list with no credential, and open.er-api.com for the dollar rate. The first full billing pull pages back through up to ten years of the account's usage. Nothing runs while the Desktop page is closed. Derived from hermes-resetwatch (Adolanium, MIT).

From the plugin's catalog listing.

## How to install

1. Install it. Hermes asks for any API keys it needs (this one needs `VILAO_PAT`), then asks whether to turn it on.

```bash
hermes plugins install hermes-call-ledger
```

2. Said no? Turn it on later:

```bash
hermes plugins enable hermes-call-ledger
```

3. Restart Hermes so it loads the plugin.

Some plugins also need a sign-in or settings: see the official page. Memory plugins ask whether to become your memory provider instead. Steps follow the official plugins guide: https://hermes-agent.nousresearch.com/docs/user-guide/features/plugins

## Facts

- Category: Cost, speed & monitoring, Hermes Desktop add-ons
- Maintained by: skappafrost (Community)
- Needs: `VILAO_PAT` (API key)
- Requires Hermes: `>=0.21.6`
- Version: 1.0.0
- In the catalog since: 2026-10-13

## Links

- [Full setup and settings (official page)](https://hermes-agent.nousresearch.com/docs/plugins/hermes-call-ledger)
- [Source code](https://github.com/skappafrost/hermes-call-ledger#readme)
- [All plugins](https://hermeswatcher.com/plugins.md)

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