Mere

A workbook format for apps. The file is the app.

A .mp.html file contains screens, state, behavior, theme, and data. Open it — it runs. Send it — it travels. No server, no account, no build step.

→ mere.semanticintent.dev

---

What it looks like

<workbook theme="proton-mail">

  <state>
    <value name="tasks" type="list" value="[]" />
    <value name="new-task" type="text" value="" />
  </state>

  <computed>
    <value name="task-count" from="tasks" op="count" />
  </computed>

  <actions>
    <action name="add-task">
      add-to tasks title @new-task
      clear new-task
    </action>
  </actions>

  <screen name="home">
    <header>
      <heading>Tasks</heading>
      <badge @task-count></badge>
    </header>
    <field ~new-task placeholder="New task…"></field>
    <button !add-task>Add</button>
    <card-list @tasks>
      <card><heading @item.title></heading></card>
    </card-list>
  </screen>

</workbook>

Save as tasks.mp.html. Double-click. It runs.

---

Four sigils. That's the grammar.

Sigil	Name	Example	Meaning
@	read	<heading @title>	One-way binding from state. On list containers, iterates the array.
~	two-way	<field ~email>	Bidirectional sync between input and state.
!	action	<button !submit>	Invokes a named action on click.
?	intent	<screen ?"Show inbox">	AI compositor annotation. Ignored at runtime.

---

26 elements. No HTML passthrough.

screen header footer form heading subtitle paragraph timestamp badge avatar icon tab-bar tab navigation-bar nav-item message-list card-list list message-card card field button toggle modal toast banner

Every element has a specific role. The vocabulary is closed by design — bounded enough for AI to generate reliably, expressive enough for real apps.

---

Installation

npm install -g mere

CLI

mere check tasks.mp.html     # validate — exit 0/1/2
mere check *.mp.html          # validate multiple, summary line
mere schema                   # print element registry
mere schema --json            # machine-readable JSON

---

Three themes

Theme	Character
classic-light	Neutral baseline. Clean cards, comfortable spacing. Default.
proton-mail	Purple accent, underline tabs, 14px base type.
brutalist	Zero radius, 3px black borders, inverted header, red accent.

---

Persistence

Add persist to any state value — saved to OPFS (localStorage fallback):

<value name="notes" type="list" value="[]" persist />

---

Why not just HTML?

HTML gives you the substrate. Mere gives you the contract.

Raw HTML has no opinions about state, data flow, or actions. Infinite choices produce inconsistent output — especially for AI generation. Mere's bounded vocabulary, explicit sigils, and text-based action syntax mean a model can produce a valid workbook reliably, because there are no escape hatches and no ambiguity.

The file runs anywhere HTML runs. Forever. No framework lock-in.

---

Examples

See examples/ for ready-to-open workbooks. Full live examples at mere.semanticintent.dev/examples.

---

Docs

• docs/concept.md — what Mere is and why
• docs/spec.md — full language specification
• docs/roadmap.md — milestones and open questions

---

License

MIT — see LICENSE.