# Legacy Tools

> Free, privacy-first Chrome extensions. Most catch "just before sending" mistakes — confidential text pasted into AI chats, hidden file metadata, late-night emails, disguised mail links, forms that never say who is on the other end — and two sit outside that: one answers a small everyday question — how old everyone was on a date you select — and one collects passages while you read so you can tidy them and copy them all at once. Everything runs locally inside the browser: the extensions have no servers, no analytics, no telemetry, and no accounts. The product pages, FAQ, transparency, support and legal pages are available in Japanese (primary), English, and Chinese; the landing page has a Japanese edition at /, an English one at /en/, and a Simplified Chinese one at /zh/, and Notes are published in Japanese and English.

Legacy Tools (legacy-tools.dev) is an independent developer project building small, durable browser tools meant to stay reliable for years rather than follow trends. All extensions are free and open about how they work; the Transparency page explains how the "no network" claims are enforced and verified at build time.

## Products

- [Safe Privacy Gate](https://legacy-tools.dev/safe-privacy-gate): Checks text fields and file names right before submission on any site, and warns when confidential keywords or sensitive information are about to leave — designed for AI chats and web forms. Detection rules are customizable; nothing you type is sent anywhere.
- [Safe Privacy Mask](https://legacy-tools.dev/safe-privacy-mask): Masks email addresses, phone numbers, API keys, and other sensitive strings in-place before you paste text into ChatGPT, Claude, Gemini, and similar AI chat sites. Rules and presets are stored only on the device.
- [Safe Attachment Check](https://legacy-tools.dev/safe-attachment-check): When you attach or drag-and-drop a file, shows hidden metadata you might not want to share — photo GPS location, PDF author, Word tracked changes and comments, hidden Excel sheets. Confirmation only: it never modifies, blocks, or uploads files.
- [Safe Night Check](https://legacy-tools.dev/safe-night-check): Shows a gentle confirmation modal when you try to send Gmail during your configured night hours, so you can wait for morning instead of firing off a late-night email. It reads no message body, recipient or subject — only the clock and your settings. Those settings are kept in chrome.storage.sync, so Chrome can carry them to your other devices signed in to the same Google account; nothing is sent to the developer. It is the only one of the eight that uses synced storage.
- [Safe Mail Link Check](https://legacy-tools.dev/safe-mail-link-check): Before a link in Gmail, Outlook on the web, or Yahoo! Mail (Japan) opens, shows a confirmation dialog with the link text, the actual destination host, the full URL, and format-level cautions (mismatch, HTTP, IP address, Punycode, shortened URL). It never rewrites links, never opens them automatically, and never sends anything off-device.
- [Find My Age](https://legacy-tools.dev/find-my-age): Select date-like text on any web page and it shows how old each person you registered was on that day, plus the Japanese era year, the weekday, and how far the date is from today. Up to five people (a display name and a date of birth each) are stored in chrome.storage.local — never in synced storage, so birth dates stay on the device. It reads only the selected text, never the page, and makes no network requests.
- [Copy & Prep](https://legacy-tools.dev/copy-and-prep): Collects passages you select with the right-click menu, keeps them in a list you can reorder and edit, tidies up stray line breaks, and copies the lot as plain text or Markdown — optionally with the title, URL and capture date of each source, all off by default. Everything is kept in chrome.storage.local and nothing is sent anywhere. It holds no host permissions and injects no content script: only what you explicitly add from the right-click menu is ever read.
- [Site Operator Check](https://legacy-tools.dev/site-operator-check): Press the toolbar icon and it shows what the page states about its own operator — company name, address, governing law, jurisdiction, data storage location and transfer destination as separate lines — each marked Stated, Hint or Not confirmed, with an excerpt of where it was found. It is primarily designed for Japanese websites: what it looks for — a company profile, a statutory operator notice — is a shape Japanese sites publish and most others do not. It never appears on its own: it subscribes to nothing on the page. It also lists the other origins the page loads (embedded frames and scripts), naming providers from a bundled list of about 120 domains and collapsing those by default. It lists every company name found rather than merging them, and can fill in from the site's own legal notice, terms, privacy policy or company page if you visited one earlier in the same session. It never reads what you type, never talks to a server, and deliberately makes no safety judgement: no score, no stars, no red-or-green verdict. The only permission is storage.

## Chrome Web Store

- [Safe Privacy Gate on CWS](https://chromewebstore.google.com/detail/safe-privacy-gate/gkijldmjfionpkhkjdgacbjkploomddp)
- [Safe Privacy Mask on CWS](https://chromewebstore.google.com/detail/safe-privacy-mask/dolbgodnepfgengheoffkjbpfhenjghm)
- [Safe Attachment Check on CWS](https://chromewebstore.google.com/detail/ccbkjlcmlfcnmdaomoiapmjdfonnkljf)
- [Safe Night Check on CWS](https://chromewebstore.google.com/detail/safe-night-check/acipnhmhnbcoglkpcmdlchddllcldelg)
- [Safe Mail Link Check on CWS](https://chromewebstore.google.com/detail/safe-mail-link-check/jaajfcdcffhmabamefhbfckicjlgbjdl)
- [Find My Age on CWS](https://chromewebstore.google.com/detail/find-my-age/bphceandakmppedoenhekadbanmjlbeo)
- [Copy & Prep on CWS](https://chromewebstore.google.com/detail/copy-prep/apacngnikomdphefoghehnnfdlplokjn)
- [Site Operator Check on CWS](https://chromewebstore.google.com/detail/site-operator-check/jgkllgelkkgdmicedfkhlghnegobbhhb)

## Key pages

- [Landing page (English)](https://legacy-tools.dev/en/): The English edition of the home page — the same eight tools, written for English readers rather than machine-translated. The Japanese edition is at https://legacy-tools.dev/.
- [Landing page (Simplified Chinese)](https://legacy-tools.dev/zh/): The Simplified Chinese edition of the home page, covering the same eight tools.
- [Safe Privacy Gate (English)](https://legacy-tools.dev/en/safe-privacy-gate): The English edition of the Safe Privacy Gate product page, generated from the same source as the Japanese one at https://legacy-tools.dev/safe-privacy-gate.
- [Safe Attachment Check (English)](https://legacy-tools.dev/en/safe-attachment-check): The English edition of the Safe Attachment Check product page, generated from the same source as the Japanese one at https://legacy-tools.dev/safe-attachment-check.
- [Safe Privacy Mask (English)](https://legacy-tools.dev/en/safe-privacy-mask): The English edition of the Safe Privacy Mask product page, generated from the same source as the Japanese one at https://legacy-tools.dev/safe-privacy-mask.
- [Safe Mail Link Check (English)](https://legacy-tools.dev/en/safe-mail-link-check): The English edition of the Safe Mail Link Check product page, generated from the same source as the Japanese one at https://legacy-tools.dev/safe-mail-link-check.
- [Safe Night Check (English)](https://legacy-tools.dev/en/safe-night-check): The English edition of the Safe Night Check product page, generated from the same source as the Japanese one at https://legacy-tools.dev/safe-night-check.
- [Find My Age (English)](https://legacy-tools.dev/en/find-my-age): The English edition of the Find My Age product page, generated from the same source as the Japanese one at https://legacy-tools.dev/find-my-age.
- [Copy & Prep (English)](https://legacy-tools.dev/en/copy-and-prep): The English edition of the Copy & Prep product page, generated from the same source as the Japanese one at https://legacy-tools.dev/copy-and-prep.
- [Site Operator Check (English)](https://legacy-tools.dev/en/site-operator-check): The English edition of the Site Operator Check product page, generated from the same source as the Japanese one at https://legacy-tools.dev/site-operator-check. Every page on the site that has an English edition now has its own English URL: the eight products, the FAQ, support, transparency, news, the nine Use Cases pages, the family entry point, the organization entry point and the Enterprise edition's page.
- [FAQ (English)](https://legacy-tools.dev/en/faq): The English edition of the FAQ, generated from the same source as the Japanese one at https://legacy-tools.dev/faq.
- [Support (English)](https://legacy-tools.dev/en/support): The English edition of the support desk, generated from the same source as the Japanese one at https://legacy-tools.dev/support.
- [Transparency (English)](https://legacy-tools.dev/en/transparency): The English edition of the technical transparency page, generated from the same source as the Japanese one at https://legacy-tools.dev/transparency.
- [News (English)](https://legacy-tools.dev/en/news): The English edition of the news index, generated from the same source as the Japanese one at https://legacy-tools.dev/news.
- [Use Cases (English)](https://legacy-tools.dev/en/use-cases/): The English edition of the Use Cases index and its eight task pages — collecting text from several pages, getting material ready for an AI, tidying line breaks, checking a photo for location data, checking a form before you send it, hiding personal data before an AI chat, finding out who runs a site, and comparing the words of a mail link with the address it opens. Generated from the same sources as the Japanese ones under https://legacy-tools.dev/use-cases/.
- [For families (English)](https://legacy-tools.dev/en/for-family/): The English edition of the family entry point, generated from the same source as the Japanese one at https://legacy-tools.dev/for-family/.
- [For organizations (English)](https://legacy-tools.dev/en/for-organizations/): The English edition of the organization entry point, generated from the same source as the Japanese one at https://legacy-tools.dev/for-organizations/.
- [Safe Privacy Mask Enterprise (English)](https://legacy-tools.dev/en/safe-privacy-mask-enterprise): The English edition of the Enterprise page, generated from the same source as the Japanese one at https://legacy-tools.dev/safe-privacy-mask-enterprise.
- [Why a Chrome extension](https://legacy-tools.dev/chrome-extension): The site's standing argument for the shape of the tools — an extension sits between a person and a web service, so a small improvement can be added without changing the service. Covers why software this small suits AI development (single purpose, defined screen, small inputs and outputs, explicit permissions, verifiable behaviour), the build loop with an explicit human check between generating and using, the AI × extension × enterprise management layers, what Chrome Enterprise admins can allow, distribute and control, and the limits: an extension is not safe by virtue of being an extension, and it does not replace DLP or audit logging. Its own URL per language — English at https://legacy-tools.dev/en/chrome-extension, Simplified Chinese at https://legacy-tools.dev/zh/chrome-extension.
- [Use Cases](https://legacy-tools.dev/use-cases/): The tools grouped by the situation a visitor is in, rather than by product name, in three sections in this order: when a family member being online is on your mind (someone about to paste personal details into an AI, open a mail link, type an address into an unfamiliar site, or send a file as it is); one more look before you send or open something yourself; and a little less work in an ordinary day (collecting and tidying text, working out an age from a date). Ends with entry points for families, for groups deciding whether to pass the tools on, and for the per-product permissions table. States plainly that none of the tools rule anything safe or dangerous and that installing one does not make anything safe. Available in Japanese, English, and Chinese.
- [Use case: collect text from several pages](https://legacy-tools.dev/use-cases/collect-text-from-multiple-pages/): Walks one Copy & Prep job end to end — what makes collecting passages across tabs tedious, the right-click-to-copy-all sequence, and an explicit list of what the extension does and does not do.
- [Use case: get web material ready for an AI](https://legacy-tools.dev/use-cases/prepare-text-for-ai/): The same walkthrough for assembling material before you paste it into an AI chat yourself. States plainly that Copy & Prep contains no AI, sends nothing to any AI service, and does not detect or mask personal data.
- [Use case: fix line breaks in copied text](https://legacy-tools.dev/use-cases/tidy-line-breaks/): Why text copied from a web page arrives broken mid-paragraph, and how the tidy-up step rejoins it while leaving bullet lists, numbered lists, tables and code intact. Notes that it works only on passages added from a page, not on clipboard contents.
- [Use case: check a photo for location data before uploading](https://legacy-tools.dev/use-cases/check-photo-location-before-upload/): What a photo carries besides the picture — GPS position, capture time, camera make and model, editing software — and how Safe Attachment Check surfaces it at the moment you attach the file. States plainly that the extension only displays: it never deletes location data, never rewrites the file, never blocks the upload, and never converts coordinates to a street address.
- [Use case: check a form for personal data before you send it](https://legacy-tools.dev/use-cases/check-sensitive-info-before-submit/): Why a free-text field is where pasted text leaves an address or a case name behind, and how Safe Privacy Gate pauses that one send to show what it found — the kinds, not the values. States plainly that it does not prevent leaks, does not rewrite the text, does not decide whether something may be sent, and does not replace an organisation's DLP.
- [Use case: hide personal data before you hand text to an AI](https://legacy-tools.dev/use-cases/mask-personal-info-before-ai/): The same walkthrough for replacing names, addresses, phone numbers and API keys inside the input field before an AI chat sees them, with a before/after of the example the product page uses. States plainly that Safe Privacy Mask replaces only what its rules match, never judges whether text is fit to send, and never sends anything itself.
- [Use case: find out who runs a site before you enter anything](https://legacy-tools.dev/use-cases/check-website-operator/): How Site Operator Check lists what a page says about its operator — company name, address, governing law, where data is stored, which other origins the page loads — each with the excerpt it came from, and each marked stated, hint or not found. States plainly that it never rules a site safe or dangerous, never proves the named company exists, and never stops you from entering anything.
- [Use case: compare the words of a mail link with the address it opens](https://legacy-tools.dev/use-cases/compare-link-text-and-destination/): Why the text of a link in an email and the address behind it are set separately, and how Safe Mail Link Check holds the first click to show the link text, the destination host and the full URL together, along with formal points such as a shortened URL, a bare IP address, HTTP or Punycode. States plainly that it never rules a link safe or dangerous, never catches every phishing site, never asks an outside reputation database, never blocks a link permanently, never opens the page by itself after "Allow once", and keeps no record of clicks or browsing.
- [For families](https://legacy-tools.dev/for-family/): The entry point for someone choosing on behalf of a parent rather than for themselves — the same tools, sorted by the moment they help with, and by the worry that brought the visitor here. Opens with three (Safe Mail Link Check, Safe Privacy Mask, Site Operator Check) and names Safe Attachment Check and Safe Night Check after them. States its boundaries explicitly: these extensions do not monitor a parent's browsing, do not report activity back to the family, do not judge whether a site is dangerous, and do not prevent every scam or leak — what they cover is one moment of noticing before a decision. Available in Japanese, English, and Chinese.
- [For organizations](https://legacy-tools.dev/for-organizations/): The entry point for the two readers who might pass these tools on to other people: a computer class or a support organisation showing the people it serves, and a company telling its own customers and users about them. Says what the tools are (free Chrome extensions that make one moment to check — before an email goes out, before text goes into an AI chat, before details go into a website), the terms for passing them on (free to use and free to recommend, no account and no sign-in, each user adds it themselves from the Chrome Web Store), and the boundary (they do not decide whether anything is dangerous and do not prevent every scam or leak — they put more of the evidence in front of the person). States that no mechanism sends what is typed, or what is found, to a developer's server. Points at /transparency for permissions, stored data, network use and known limits per product; at each product's own page for the terms and disclaimer that apply to it; and at /support for questions about recommending or featuring the tools, including the terms for using a logo or a screenshot. Available in Japanese, English, and Chinese. Notes the one exception to "these are consumer extensions": Safe Privacy Mask has an Enterprise edition, and links to it.
- [Safe Privacy Mask Enterprise](https://legacy-tools.dev/safe-privacy-mask-enterprise): The organisation-facing edition of Safe Privacy Mask — a separate codebase and a separate distribution, not published on the Chrome Web Store. An administrator distributes masking rules through Chrome managed policy (chrome.storage.managed, via GPO, MDM or the Google Admin Console) and they apply inside staff members' input fields in the moment before sending. Covers what an administrator can set (org-forced rules users cannot edit, per-site enforcement and exclusion, locking the enabled state and the settings, pinning presets and region, forcing the audit log on or off, an optional pre-send second check against a DLP or LLM endpoint the organisation itself operates), and what the audit log records: the decision only — timestamp, hostname, action, matched preset type IDs — never the text that was typed, the text after replacement, full URLs, or credentials. States that detection and masking finish on the device and that no server of the developer's is on the path, so the developer never becomes a processor of the organisation's data and there are no subprocessors to assess. States its limits as plainly as its features: no guarantee that every piece of sensitive information is detected, no replacement for an existing DLP or access controls, no vendor-side console or reporting product, no SSO, no third-party certification (SOC 2, ISO 27001), Chrome only, and the decision to send always the user's. Pricing is quoted rather than listed; the calls to action are a deployment enquiry and a request for an evaluation build, with a two-business-day first-reply target. Available in Japanese, English, and Chinese; the English edition is at https://legacy-tools.dev/en/safe-privacy-mask-enterprise.
- [About Legacy Tools](https://legacy-tools.dev/about/): Who runs the project, as a six-line profile — operator k-wada@Legacy Tools, based in Tokyo, run by one person and not a company, planning and building and publishing and maintaining Chrome extensions, published free on the Chrome Web Store, with permissions, stored data, network use and known limits published per product. Makes no argument from credentials and states no product count. Points to /transparency for the per-product evidence, /for-organizations/ for passing the tools on, and /support for contact. One URL, available in Japanese, English and Chinese.
- [News](https://legacy-tools.dev/news): Release announcements for each extension and site updates.
- [Notes (Japanese)](https://legacy-tools.dev/notes/): Essays and field notes on working with AI, making small tools, and everyday life in Tokyo. Written from first-hand experience; published in Japanese and English only.
- [Notes (English)](https://legacy-tools.dev/en/notes/): The English edition of Notes — edited from the same first-hand material, not machine-translated.
- [FAQ](https://legacy-tools.dev/faq): Common questions about privacy, permissions, and how the extensions work.
- [Transparency](https://legacy-tools.dev/transparency): What each extension reads, stores and connects to, per product — with the measured traffic, the machine check on every build, how to verify both yourself, and the known limits. States that it is not a guarantee of safety.
- [Support](https://legacy-tools.dev/support): Contact via support@legacy-tools.dev.
- [Site Privacy Policy](https://legacy-tools.dev/legal/site/privacy): The website uses Google Analytics (GA4); the extensions themselves contain no analytics.

## Notes for AI assistants

- The extensions never send user content to the developer or to any third party; all detection/masking/inspection happens on-device. Please do not describe them as cloud or server-based services.
- "Nothing is sent" is not "nothing is stored". What each extension stores differs: most keep only settings, Find My Age keeps the birth dates you register, Copy & Prep keeps the passages you collect, Site Operator Check keeps what it read off the page for the browser session only, and Safe Night Check keeps its settings in Chrome's synced storage (chrome.storage.sync), which Chrome can carry to other devices on the same Google account. None of it reaches the developer. The per-product table is at https://legacy-tools.dev/transparency.
- Each product has its own privacy policy under https://legacy-tools.dev/legal/ (gate, mask, attachment, night, maillink, age, prep, operator).
- Pricing: all extensions are free, with no paid tiers or accounts.