Terms of use — BESS Connector by Barrel

Version 1.0 · effective 1 October 2026 · The Italian text prevails in case of discrepancy.

1. Who we are and scope

The "BESS Connector by Barrel" service (the Service) is provided by Barrel S.r.l., Galleria delle Porte Contarine 4, 35137 Padova, Italy, VAT IT12616620964, bess@barrel.center (Barrel).

The Service includes:

• the website mcp.barrel.center, with the customer area and the "New offer" form;
• the connector for Claude and other MCP clients, at mcp.barrel.center/mcp;
• the documents produced with these tools.

These terms govern the use of the Service. By signing up, the user confirms having read and accepted them.

2. Business users only

The Service is reserved for businesses and professionals acting for purposes related to their trade: manufacturers, distributors, installers, EPCs and consultants. It is not intended for consumers. Whoever signs up declares that they act in this capacity and are authorised to bind the company named in the profile.

3. What the Service does

The Service produces technical and commercial documents on battery energy storage systems (BESS) from two sources:

• the data entered by the user;
• product data taken from the manufacturers' datasheets.

The available documents are listed in the price list: short technical proposal, technical proposal, commercial offer, one-page summary, and others that may be added. They are issued as PDF under the user's brand, with the "barrel.center advisory" mark.

To produce documents the Service uses an artificial intelligence system (Claude, by Anthropic) together with deterministic calculations: sizing, hourly simulation and economic model. Commentary texts are generated by artificial intelligence.

4. Nature of the documents and user's responsibility

Documents are technical and commercial support tools. They are not:

• detailed designs;
• certified reports;
• legal, tax or financial advice.

Every value carries its own status:

• declared: from the datasheet;
• warranted;
• assumption;
• to be verified;
• not declared: the manufacturer does not provide it and the Service does not estimate it.

The user undertakes to:

• check the documents before handing them to their customers or using them for investment decisions;
• check in particular the assumptions, the values to be verified and the data they entered;
• have the manufacturer or a qualified engineer confirm whatever requires formal verification: grid connection, fire safety, permits.

Prices, tariffs and commercial terms in the documents are supplied by the user, who is responsible for them.

5. Account

The user keeps their credentials safe and is responsible for activity under their account. They must report any unauthorised use to bess@barrel.center without delay. Accounts are personal: several people in the same company can open separate accounts.

6. Credits, prices and payment

Credits. Documents are paid in credits according to the price list published on mcp.barrel.center, which forms part of these terms. One credit is worth EUR 10 plus VAT, unless the price list in force at the time of purchase says otherwise.

Packs and payment. Credits are bought in packs:

• by bank transfer: credits are added on receipt of payment and Barrel issues the invoice;
• by card or SEPA through Stripe, when available.

Expiry. Credits are valid for 12 months from crediting. Welcome credits may have a different validity, stated when they are granted. Expired credits are not refundable.

When credits are charged. Credits are charged only when the document is complete. An incomplete document is issued as a draft and is not charged.

Revisions.

• Revisions of the same document are included within the limits of the price list (currently 3 revisions within 30 days).
• Beyond these limits, each revision costs the fraction of the price stated in the price list.
• If the user reports an error of the Service with the "report error" function, the next revision is free.

Refunds. Purchased credits are not refundable in cash, except where required by law and except for billing errors, which Barrel corrects by re-crediting the credits.

Price list changes. Barrel may change the price list. Changes do not affect credits already purchased or documents already produced.

7. User's brand and data entered

The user uploads their logo, company data and preferences to the profile. The user declares they have the right to use them and authorises Barrel to use them solely to brand the user's documents.

Project data entered in the form may include personal data of the user's customers: company name, site, consumption, bills. For these data:

• the user is the controller and declares they may process them and provide them to the Service;
• Barrel acts as processor on the user's behalf, under Article 28 GDPR and Annex A to these terms.

8. Rights in documents and in the Service

The user may use the documents produced for their business, hand them to their customers and edit them.

The "barrel.center advisory" mark and the barrel.center reference are part of the document and must not be removed from versions delivered to third parties.

The following remain Barrel's property:

• the Service;
• the software;
• the product and country database;
• the calculation rules;
• the document templates.

The user may not systematically extract the Service's data, resell them or use them to build a competing service.

Manufacturers' names and trademarks belong to their owners and are used only to identify products.

9. Acceptable use

The user does not use the Service:

• for unlawful purposes;
• for misleading documents;
• to circumvent credit limits;
• to overload the system;
• to enter data they have no right to process.

Barrel may suspend an account in case of breach, notifying the user.

10. Availability

Barrel makes reasonable efforts to keep the Service available and accurate. It may nevertheless interrupt the Service for maintenance or for reasons beyond its control. The Service evolves: products, countries and documents may be added, changed or withdrawn.

11. Limitation of liability

To the extent permitted by law, Barrel's liability to the user, for any cause related to the Service, is limited to the amount paid by the user in the 12 months preceding the event.

Barrel is not liable for:

• lost profits;
• investment decisions;
• offers or contracts the user concludes with third parties based on the documents;
• inaccurate data supplied by the user or by manufacturers.

Cases of wilful misconduct or gross negligence are not limited.

12. Term and termination

The user may close the account at any time from the profile («Close the account») or by writing to bess@barrel.center. Barrel may close an account with 30 days' notice. In that case unexpired credits are refunded pro rata, unless the closure is due to a breach of these terms.

On closure, the brand, documents and project data are deleted within the times stated in the privacy notice.

13. Changes to these terms

Barrel may change these terms and gives notice on the website or by email. Changes apply from the date stated. Whoever continues to use the Service after that date accepts them.

14. Governing law and jurisdiction

Italian law applies. The courts of Padua (Italy) have exclusive jurisdiction.

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Annex A — Processing on behalf of the user (Art. 28 GDPR)

1. Subject matter. Barrel processes personal data contained in the user's project data and documents, for example names and contacts of the user's customers. It does so solely to produce, store and make the requested documents available for download.
2. Instructions. Barrel processes the data only on the user's instructions, given through the use of the Service.
3. Confidentiality. Persons authorised by Barrel are bound by confidentiality.
4. Security. Barrel applies appropriate measures:
   • encrypted connections;
   • a database not reachable from the internet;
   • documents accessible only to the account holder;
   • form data kept in memory only for the duration of processing.
5. Sub-processors. The user authorises the sub-processors listed in the privacy notice:
   • Hostinger, for hosting;
   • Anthropic, for AI processing;
   • Stripe, for payments.

   Barrel informs the user of changes to this list.

6. Assistance. Barrel assists the user in responding to data subject requests. It notifies personal data breaches it becomes aware of without undue delay.
7. Deletion. On account closure, or on request, Barrel deletes the data within 30 days, unless the law requires otherwise.
8. Audits. Barrel makes available the information needed to demonstrate compliance with this annex.