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Glazecalc

by AaronFilsonversion 1.4.0i★ –iRuns in the cloud
Registry namecom.glazecalcapp/glazecalc

Install

Overview

Description from the maker (original English)

Ceramic glaze chemistry: unity formulas, limit checks, substitutes, cones and potters' guides.

PopNx MCP’s three pillars

These three are never merged into one score: opinions, measurements and popularity are different things.

What you can do with it

We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.

  • Connection: Runs in the cloud
  • Transport: Streamable HTTP
  • Category: Developer tools
  • You need to fill in: Authorization

Install

Pick the AI app you use, then copy the settings.

Before you install

Values marked secret are keys to your account. Never share them or paste them into a chat.

You need

Which app do you use?

Pick your app above. We remember it, so next time the button says “Install in …”.

This address needs a key in a request header, which the add-connector menu cannot set. Use Claude Code, Cursor or VS Code instead.

Run this in your terminal

claude mcp add --transport http glazecalc https://glazecalcapp.com/mcp --header 'Authorization: your-value'

Fill in the empty values before running it.

Open in Cursor

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

{
  "mcpServers": {
    "glazecalc": {
      "url": "https://glazecalcapp.com/mcp",
      "headers": {
        "Authorization": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

Open in VS Code

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "glazecalc": {
      "type": "http",
      "url": "https://glazecalcapp.com/mcp",
      "headers": {
        "Authorization": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

This address needs a key in a request header, which the add-connector menu cannot set. Use Claude Code, Cursor or VS Code instead.

Your choice stays on this device in a cookie; no account needed.

Values you fill in

  • Authorization secret HTTP header
    Only for your own saved records, and only if your app does not connect through Glazecalc sign-in: "Bearer " and a personal access token made on your Glazecalc account page, read only or read and chan…

These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.

What it can do

Tool names and descriptions exactly as the server reported them on Nov 6, 2026. The maker wrote them, not us; we show them as plain text.

  • search_materials

    Finds ceramic raw materials (feldspars, clays, frits, fluxes) and, if asked, colorants in Glazecalc's library by name, alias or maker. Use it to find the exact name the other tools take.

  • get_material

    One material from Glazecalc's library: its oxides, loss on ignition, whether it is discontinued and what replaces it, where it is sold, hazards and the data sheet it comes from.

  • analyze_recipe

    Works out a glaze recipe's unity (Seger) formula, oxide groups, silica to alumina ratio, fired analysis, loss on ignition and calculated thermal expansion, as the Glazecalc app does. stull says where the recipe sits on Stull's chart (1912, as the recipe page draws it): silica and

  • check_limits

    Checks a glaze recipe for what is past a recommended limit for its firing (too much boron or alkali, too little alumina, too little or too much clay, rising expansion...) and says what the fired glaze will likely do, as the Glazecalc app does. A cone is checked in the band the re

  • convert_cone_temperature

    Converts between a pyrometric cone and its temperature, and between °C and °F. Orton cones run 022 to 42: Glazecalc's figure, from 022 to 15, is Orton's older chart for large cones at 150 °C an hour, and Orton's current figures (self-supporting cones at 15, 60 and 150 °C an hour,

  • specific_gravity_water

    Works out a glaze slurry's specific gravity (SG) from the grams 100 mL of it weighs (or takes the SG), then, for a bucket of it and a target SG, the water to add, or to pour off after the glaze settles, as the recipe page's Specific gravity and water does. The water to add needs

  • suggest_substitutes

    Finds the discontinued or scarce materials in a recipe and the modern ones that replace them, then suggests amounts that keep the unity formula as near as the materials allow, as the Glazecalc app does. report.closeness says how near the new unity formula comes to the old, oxide

  • match_from_materials

    Remakes a glaze recipe from only the materials listed in "have", keeping its unity formula as near as they allow, as Match with what I have does in the Glazecalc app. report.closeness says how near the new unity formula comes to the old, oxide by oxide: close (within 0.02, or 5%

  • solve_target

    Makes a glaze recipe, in percent, from the materials given whose unity formula comes as near a target as they allow (Solve for a target in the Glazecalc app). The target is a unity formula (moles; the fluxes are scaled to add up to 1) or an oxide analysis (percent by weight of th

  • blend_recipes

    Works out the test tiles of a line blend between recipes a and b (2 to 11 steps), or of a triaxial blend when c is given too (2 to 6 rows, up to 21 tiles), as the Blends page of the Glazecalc app does. Each tile is a mix of the corner recipes, each taken as a percent of its base:

  • vary_material

    Shows what one material does to a glaze, by putting more and more of it into a base recipe (an ingredient blend or progression test: whiting 0 to 20, say, in 2 to 11 tiles). With mode "add" (the default) it goes on top of the base, so the recipe grows; with mode "replace" the sam

  • compare_recipes

    Compares two glaze recipes side by side: for each, its recipe in percent, key unity formula figures, flux ratio (R2O against RO), silica to alumina, calculated expansion, place on Stull's chart (stull), the names of the limit cautions it has and, with a firing, whether its chemis

  • search_guides

    Searches Glazecalc's plain-language guides for potters (glazing from first principles, making a glaze, safe mixing, safety at home with children and pets, firing a kiln, and a companion to John Britt's free glaze course, in English only) in the language asked for, or in English w

  • list_recipes

    Lists the glaze recipes saved in your Glazecalc account, newest first, optionally only those whose title or a material matches a search, or whose stated firing includes a cone or names an atmosphere or process ("which of my glazes fire at cone 10 reduction?"). Each lists its stat

  • get_recipe

    One recipe from your account: its materials and amounts, colorants, notes, its stated firing (firedAt: the cone scale, the low and optional high cone of the claimed range, the cones actually tested, the atmospheres and processes, and for a temperature the rate and hold; each cone

  • list_my_materials

    Lists the materials you have saved in your own Glazecalc account (not the shared library), with their oxides.

  • get_shelf

    The materials you marked as on hand in Glazecalc (the shelf that Match with what I have uses).

  • match_with_what_i_have

    Remakes one of your recipes, or a recipe you give, from only the materials on your shelf, keeping its unity formula as near as they allow (Match with what I have). report.closeness says how near the new unity formula comes to the old, oxide by oxide, as match_from_materials does.

  • list_firings

    Lists the firing logs saved in your Glazecalc account, newest first.

  • get_firing

    One firing log from your account: its columns (time, temperature, cone...) and rows, and its notes.

  • list_notes

    The notes in your Glazecalc notebook, newest first, optionally only those about one record (a recipe, material or firing log id).

  • get_my_settings

    Your Glazecalc settings that matter when talking about glazes: region, temperature scale, cones, language, weight unit, whether lead may be suggested, the limit set recipes are checked against, the currency your prices are in (never the prices), and whether changes made by assist

  • create_recipe

    Saves a new glaze recipe in your Glazecalc account, from its base materials and amounts (the library's names, or your own materials'), with optional colorants, notes, firing band and food-surface mark. Glazecalc works out its unity formula, as the recipe page does, and answers wi

  • update_recipe

    Changes one of your saved recipes (an id from list_recipes): its title, its base materials and amounts (the unity formula is worked out again), its notes, firing band or food-surface mark. Only what is given changes. The recipe as it was is kept as an earlier version, so the pers

  • add_notebook_entry

    Adds an entry to your Glazecalc notebook (the Notebook page), with an optional title: a test result, an observation, a firing to try. With about, it is a note about one of your recipes, materials or firing logs, which list_notes finds by that record's id. Needs an access token th

  • add_my_material

    Saves a material of your own in your Glazecalc account (the Materials page) from its oxide analysis in weight percent, as on a data sheet, with its loss on ignition. Recipes can then use it by name. Needs an access token that can read and change your records.

  • update_my_material

    Changes one of your own materials (an id from list_my_materials): its name, oxide analysis in weight percent, loss on ignition or notes. Only what is given changes. Recipes already saved keep their own copy of it. The material as it was is kept as an earlier version, so the perso

  • add_to_shelf

    Marks materials as on hand (the shelf that Match with what I have uses), by the library's names or your own materials'. The shelf as it was is kept: undo_shelf_change puts it back. Needs an access token that can read and change your records.

  • remove_from_shelf

    Takes materials off the shelf of materials on hand, by name. The materials themselves stay. The shelf as it was is kept: undo_shelf_change puts it back. Needs an access token that can read and change your records.

  • undo_shelf_change

    Puts back the shelf as it was before its last change (by the website, an access token or an assistant). One step back only: a second call finds nothing to undo until the shelf changes again. Needs an access token that can read and change your records.

  • move_to_trash

    Moves one of your recipes, materials, notebook entries or firing logs to the Trash, as removing it on the website does. It can be put back from the Trash on the website for 30 days; nothing is deleted for good. A token moves at most 100 an hour, and none while the Trash is full.

  • create_firing_log

    Saves a new firing log in your Glazecalc account (the Firing page): its title, the day, the kiln, the columns kept (time, temperature, cone, atmosphere, comments...) and a row for each reading, as the person dictated them. Add later readings with add_firing_rows. Save only what t

  • add_firing_rows

    Adds rows to the end of one of your firing logs (an id from list_firings), in the log's own columns (get_firing gives them): the readings dictated during a firing. The rows already there stay as they are, and the log as it was is kept as an earlier version. At most 500 rows a log

  • link_firing

    Links one of your recipes to a firing log it went through, as the recipe page does, and sets what came of it there: the result in the person's words (at most 500 characters), and the cone and atmosphere when they differ from the log. Linked already, it changes only what is given.

Basic checksi

We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 7, 2026

  • ! Caution

    Maker matches the repo

    The publisher (glazecalcapp.com) is not the repo owner (AaronFilson); someone else may have listed it

  • … Not checked yet

    Still maintained

    We have not read this repo from GitHub yet

  • … Not checked yet

    Has a licence

    We have not read this repo from GitHub yet

  • ✓ Pass

    Endpoint responds

    Responded in 258 ms (HTTP 200)

  • – Not applicable

    Sign-in with OAuth

    No sign-in needed

  • ✓ Pass

    No hidden instructions in tool descriptions

    Read 34 tool descriptions and found no hidden instructions to the AI

Compared with others in Developer toolsi

  • More stars than 0% of the other 4907 servers in this category
  • Published to the registry more recently than 90% of the other 4907 servers in this category
  • Basic checks equal to or better than 23% of the other 4907 servers in this category

Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.

Common questions

Is Glazecalc safe?

It passed 2 of 3 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.

What keys or codes does it need?

You need to fill in: Authorization

Does it run on my computer or in the cloud?

It runs in the maker’s cloud. Connect over the internet with nothing to install, but what you send passes through the maker’s servers.

Is it still maintained?

The GitHub repo last changed –, and the latest version (1.4.0) reached the registry 4 days ago.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. It connects by URL, so apps that accept remote MCP servers work too, such as ChatGPT in developer mode.

What can I use instead?

In the same category: GitHub, Desktop Commander, Cloudflare MCP

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README from the maker

Open the README

Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.

Glazecalc

Free glaze chemistry for potters. Enter a glaze recipe and see its unity molecular formula (UMF): the fluxes, alumina and silica it becomes in the kiln, and their ratio. Keep your recipes, materials, colorants, firing logs and notes together in one private notebook.

[glazecalcapp.com](https://glazecalcapp.com): try it without an account. A non-profit project by Aaron Filson, in 57 languages, and usable from AI assistants through its MCP server.

What it does

  • Recipe to unity formula, as you type. Build a glaze from your own materials or the standard ones and watch its oxides in unity, grouped as fluxes, stabilizers and glass formers, with the silica to alumina ratio. That is how glaze chemists compare recipes, fix faults and substitute materials. Change the scale to percent, to the smallest whole parts, or to a batch in grams or in pounds (each shown in pounds and ounces), with colorants as a percent of the base, in parts or in grams; save a recipe and keep working on it, or open a saved one to change it.
  • Compare two recipes side by side, oxide by oxide and by calculated thermal expansion, and try an old recipe with the modern materials that replace its discontinued ones (Custer Spar to G-200 EU), compared with the original. Where a swap is not like for like, it works the amounts out again, changing as few as it can, from materials sold in your region or any you add, and says what each one does and what to watch for past a recommended limit.
  • Match with what I have: make a recipe again from only the materials on hand, a list kept with your account.
  • Analysis and limits: the unity formula set against Hesselberth & Roy's stable glaze limits or Glazecalc's own, for the firing saved with the recipe, and a Stull chart of silica against alumina with its matte, semi-matte and bright regions.
  • Specific gravity and water: weigh a measured volume of the glaze to find its SG, then the water that brings the bucket to the SG you want, or the water for a new batch.
  • Paste in recipes from a website, a spreadsheet or your notes: see how each line was read and which material it was taken for before anything is saved.
  • Blends for test tiles: two, three or four of your recipes blended into numbered tiles, with what to weigh for each and the chemistry of each tile.
  • Cost per batch from the prices you pay, kept private with your account in one currency, and a mix ticket to print for the glaze room, with the batch number, the target SG and the materials' hazards (prices left off unless you choose).
  • Share a recipe with a read-only link that anyone can open without an account, with its unity formula and how it is worked out, step by step; stop sharing at any time.
  • Sign in with Google, GitHub or Microsoft, or with a password, two-step sign-in or a passkey.
  • Use it from your AI assistant: Claude, ChatGPT, GitHub Copilot, Cursor, Gemini and others can use the calculations through the Model Context Protocol (MCP) server at /mcp, and your own records once you connect them: apps sign in to Glazecalc's own OAuth server and you say yes (read only unless you also allow changes), or you make an access token for them. Connected apps shows what each one did, puts back what it moved to the Trash and revokes it; the Assistants page says how to connect one.
  • Guides for new potters, sourced: glazing from first principles with a glossary, how to make a glaze, safe mixing and ventilation, pottery at home with children and pets, and firing a basic kiln with cones, kiln sitters and manual switches; and, in English, a companion to John Britt's free online Glaze Course that links his videos unit by unit with exercises to try; and, in English and Japanese, a six-session pack for teaching glaze calculation.
  • Famous glazes, each a public page with its traditional recipe or historic analysis and a version from the materials sold where you live (İznik first, as history, with a lead-free version not yet test-fired).
  • Specific gravity and water, with the dry materials' SG estimated from the recipe (or typed, or measured as the making-a-glaze guide shows).
  • Lead off unless you choose it, and old lead glazes rebuilt without it: Replace lead keeps the glaze's silica and alumina and gives lead's work to boron and other fluxes, on a lead-free base frit sold in your region with up to four other materials chosen for it, or keeps the colour on a lead-free base.
  • Print it for the glaze room: the whole recipe with its unity formula and analysis, or just a batch list to tick off while weighing, with a running total for weighing into one bucket. One page on Letter or A4; weights in grams, or in pounds and ounces as set in your account.
  • Your region and your numbers: where you work sets numbers and dates as you write them (12,5 or 12.5 typed either way), °C or °F, Orton cones, SK cones (JIS R 8101) or firing by temperature, the standard materials sold there, and in the guides: who to call in an emergency for 72 countries, and for 41 of them shops that sell glaze materials, the closest materials sold there to those a recipe names and the workplace limit for silica dust, with food-contact limits for glazed ware for 42; each checked on an official or the shop's own page.
  • Translated into 57 languages: an official language of every country of the EU (Bulgarian, Croatian, Czech, Danish, Dutch, English, Estonian, Finnish, French, German, Greek, Hungarian, Irish, Italian, Latvian, Lithuanian, Maltese, Polish, Portuguese, Romanian, Slovak, Slovenian, Spanish, and Swedish), Japanese, Turkish, Traditional Chinese, Korean, Simplified Chinese, Thai, Vietnamese, Indonesian, Arabic and Urdu (right to left), Hindi, Bengali, Tamil, Marathi, Kannada, Telugu, Gujarati, Malayalam, Punjabi, Odia, Nepali, Sinhala, Latin American Spanish, Brazilian Portuguese, Swahili, Amharic, Afrikaans, Hausa, Yoruba, Zulu, Igbo, Somali and Quechua, each at its own addresses (/de/recipe).

Translated by AI with a glossary per language from suppliers' catalogues, reviewed, and the safety text checked by translating it back; every translated page says so and links to a form to suggest a better wording.

Every piece of text is a message (Transloco with ICU plurals), and the guides are Markdown per language (how translations are made).

  • Your own colors: light, dark or as the device is set, and six palettes named for glazes, each readable in both.
  • A standard library of 182 materials and 37 colorants and additives, from manufacturers' data sheets (and, for ashes and historical native materials, published research), for the US, UK, EU, Australia, New Zealand and the other regions, each with its source and other names, and hazards where the data sheet gives them, each with its own public page in every language. Discontinued materials stay for old recipes, each pointing to its modern replacement. Count colorants in the unity formula or leave them out, to compare with other calculators.
  • Your own materials, from a chemical formula or a supplier's analysis, and colorants and opacifiers on top of a base glaze.
  • A studio notebook: firing logs (times, temperatures, cones), notes, and plain-language advice on mixing, glazing and firing.
  • Try it now: the whole app works as a trial with a generated name such as "speckled quiet kilns". Creating an account keeps everything; trials are removed after 14 days.
  • Light and dark mode, from phone to desktop. Free and open source.

Highlights

For anyone reading the code:

  • A 2017 AngularJS app rebuilt as Angular 22 (standalone components, signals, no zone.js, strict templates) and a TypeScript server on Express 5, Mongoose 9 and Node 24, which runs the .ts files directly with no build step (ADR 8), and put back online. The case study tells how.
  • Tested at three levels, in CI on every pull request and push to master: about 1,000 server tests (98% of statements) run against the app in-process; over 700 Angular unit tests (92%); about 175 Playwright browser tests, including axe accessibility checks of every page in light and dark mode, every page in a pseudo-locale to find text not marked for translation, and every page in each language at a phone's width.
  • One glaze chemistry library for the browser and the tests, checked against values worked out by hand (ADR 4).
  • Keyless deploys with approval: GitHub Actions gets short-lived AWS credentials through OIDC, for a role that can only run one SSM command document on this app's instance. There is no SSH, there are no stored AWS keys, and a failed health check rolls back (ADR 2).
  • Production for about $13 a month: one Graviton EC2 instance with Docker Compose, nginx and Let's Encrypt, a content security policy with subresource integrity, nightly backups to S3, snapshots and alarms (ADR 1, ADR 3).
  • Careful accounts: bcrypt; HS256 tokens with a version, so changing the password signs out every device, kept in an httpOnly, SameSite=Strict cookie with a cross-site request check; hashed single-use reset links sent through Amazon SES with DKIM, SPF and DMARC; rate limits; ownership checks on every query; the current password to change the email or delete the account (ADR 5, ADR 6).
  • Two-step sign-in and outside providers: passkeys, authenticator apps and recovery codes (ADR 14); Google and GitHub linked by the provider's id, never silently by email (ADR 15); Microsoft by tenant and subject (ADR 23).
  • AI assistants as first-class clients: a stateless MCP endpoint sharing the app's recipe tools (ADR 17, ADR 19), Glazecalc's own OAuth authorization server (ADR 24), and changes from an app that wait for the person's yes (ADR 25).
  • A translation pipeline for 57 languages: Transloco with ICU messages and the language in the URL (ADR 13); per-language glossaries sourced from suppliers' catalogues, staged reviews, blind back-translation of the safety text, and a plain notice for languages AI translates less well (process); `npm run check:i1

Only the beginning is shown; read the rest in the repo

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