Privacy Policy

Last updated: 2 October 2026

Equation.io works without an account. Graphs are encoded in URLs, imported CSV files stay in your browser, and requests to our MCP server are processed on Cloudflare. Interacting with an Equation.io widget within an AI client may share graph content and edits with that client. A graph link is not private: anyone who has it can read its equations.

2 October 2026 update: We now count MCP tool calls, recording the tool, the client name, the types of graph and how many rows had errors, but never the equations. We also use Cloudflare's built-in analytics to count visitors to each page.

15 September 2026 update: This policy now covers interactive graphs within AI clients and the data that may be shared when you use them.

Who runs Equation.io

Equation.io is operated by Anthony Foster in Australia. This policy covers the graphing calculator at equation.io and its MCP server, including use through ChatGPT, Claude, and other clients. For privacy questions or requests, email support@equation.io.

Information we process

• Website requests. Cloudflare processes network and request information to deliver and protect the service, such as IP addresses, requested URLs, timestamps, browser information, and errors.
• Graph content. Equations, definitions, labels, and values are encoded in graph URLs. Opening a /g/ link or requesting a preview sends that content to the server. URL fragments (the part after #) are not sent in the initial HTTP request, but the app can convert graph state to a shareable URL path; do not treat fragment links as a confidentiality feature.
• MCP requests. Your AI client may send equations and graph links to our server to validate, create, display, or read graphs. We return results to the calling client. The integration does not request your full chat history, contacts, account credentials, or access to files on your device. For each tool call we record the tool, the client name from the request's User-Agent header, the types of graph it contains (such as a 2D curve), how many rows it had, and how many of those had errors. We never record the equations.
• Interactive widgets. Interacting with an Equation.io widget within an AI client may share graph content, edits, and related settings with that client. The client may use this information to support the conversation and save or restore your graph.
• Support. If you contact us, we receive your email address and the information you choose to send. GitHub issues and their attachments are public; use email for private requests.

Local files and browser storage

CSV files imported into the calculator are parsed locally and stored in your browser using IndexedDB when available. The calculator does not upload those file bytes to our server. A graph can still include a file name, a content fingerprint, column names, or values you enter into equations, which can become part of a shared URL. Files you separately attach to an AI service are governed by that service's practices.

We use local storage for preferences such as theme and equation-panel size and position. These are functional settings, not advertising identifiers. You can remove imported files in the app or clear Equation.io's site data in your browser. Browser storage can also be removed by your browser; keep your own copy of important files.

How information is used and shared

We use information to provide graphing and previews, answer tool calls and support requests, understand how the calculator and its MCP tools are used, diagnose errors, and protect the service against abuse. We do not sell personal information or use graph content to train AI models.

Cloudflare provides hosting, network delivery, security, and operational telemetry. Request logs can include URLs and therefore equations in URL paths. We disabled Cloudflare Web Analytics on 14 September 2026. We continue to use Cloudflare's built-in analytics to monitor request volume and service health, and to count visitors to each page by IP address. MCP tool-call counts are stored in Cloudflare Workers Analytics Engine. See Cloudflare's privacy policy.

Your AI client, any MCP gateway you choose (such as Smithery or Glama), and any service where you share a graph may process and retain tool inputs, outputs, URLs, and preview images under their own policies. Your AI client may also process and retain information shared through your interactions with the widget. Direct connections and connections through a gateway have different recipients. Those services are not controlled by Equation.io.

Information may also be disclosed when required by law or reasonably necessary to investigate abuse or protect legal rights. Hosting and other service providers may process information outside Australia, including in the United States and other countries where they operate.

Retention

• Tool processing: the MCP implementation processes inputs in memory for the request and does not maintain an account database or a saved-graph collection. This does not prevent request metadata, errors, URLs, or cached responses from being retained by infrastructure or clients.
• Operational logs: Cloudflare Workers Logs has a documented retention period of three days on its free plan and seven days on its paid plan. Other Cloudflare security and analytics products have separate retention periods. Data collected by Cloudflare Web Analytics before it was disabled may remain available under its retention policy, which provides access to the previous six months of data; disabling collection does not establish that historical data has been deleted. See Workers Logs and Web Analytics retention.
• MCP usage counts: kept for three months in Workers Analytics Engine. They contain no equations, IP addresses, or account information.
• Previews: generated preview-image responses permit public caching for up to 24 hours. Browsers, messaging services, and other recipients can keep their own copies.
• Local data: imported CSV files and preferences remain in your browser until removed, cleared, or evicted by the browser. History and synced bookmarks follow your browser's settings.
• AI client data: information shared with your AI client is subject to its retention policy and available deletion controls. Equation.io does not control how long that client retains it.
• Support: correspondence may be retained indefinitely, including after a request has been resolved. You can ask us to delete it.

Your choices and requests

Do not include passwords, confidential information, or sensitive personal data in graph URLs. Encoding is not encryption. Anyone with the link can recover its contents, and Equation.io cannot revoke a URL or erase copies held by others.

You can clear local site data, delete your own browser history and bookmarks, stop using the service, and disconnect the MCP connector in your AI client. Contact the relevant AI service or gateway to manage data it holds.

You can use the standalone calculator at equation.io without an AI client. Clearing Equation.io's browser storage or disconnecting the connector does not delete information already held by your AI client; use that client's available data controls.

Email us to request access to, correction of, or deletion of personal information we hold, or to raise a privacy complaint. We may need enough information to verify your request, but please do not send identity documents or secrets unsolicited. We will respond within a reasonable time and explain any information we cannot locate or delete, including information retained to meet legal obligations. You may also contact the Office of the Australian Information Commissioner or your local privacy authority where applicable.

Changes to this policy

We will update this page and its date when our practices change. We will highlight material changes on the site.