Rio

Text editor & development environment

Back to the future.

A lightweight IDE in the spirit of ’90s desktop software.

adr/0128-mit-license.mdRaw Markdown · GitHub ↗

ADR-0128: rio is MIT-licensed

  • Status: Accepted; amended by ADR-0129
  • Date: 2026-09-20
  • Deciders: jka
  • Decision: D121

Context

rio carried no LICENSE file, no licence headers and no SPDX identifier. The default for a work published without a licence is all rights reserved: the source may be read and nothing more — not run, not forked, not passed on. Every other assumption the project makes about being copied (clone it, mirror it, deploy it onto another box) had no legal basis underneath it. RELEASING.md records this as Gate 1, and marks it the one hard blocker among the release gates.

The expensive half of licensing a codebase is establishing what is actually in it. That was already done, for its own reasons: ADR-0127 removed the last third-party asset — the stock window icon — and replaced it with artwork the project owns. Editor, core, protocol, agent loop, highlighters, themes and icon are all the project's own work, so a single licence can cover the whole tree with nothing carved out of it.

Decision

rio is released under the MIT License. LICENSE at the repository root holds the standard text verbatim, unedited, with the copyright held by Julius Kaiser.

The documents that had promised a licence now state it, each in its own register: README gains a short License section; CONTRIBUTING answers the contributor's question — a change sent to rio is offered under the same licence, with no agreement to sign and no copyright assignment — and points at the icon rule as the same question in its sharpest form for whatever a change brings with it; ROADMAP and RELEASING keep only the code-of-conduct half of their entries open.

The licence is also shown in the running program. Help ▸ About rio (ADR-0076) gains a fourth facts row, License: MIT, after Build, Date and Protocol. Those three identify the build; the licence identifies the copy, which is what the person holding it needs to know and the one fact there they should not have to find a repository to read. The name is written in the dialog rather than read from LICENSE at run time — the file need not sit beside a deployed GUI — so the fact has two homes and therefore a guard rather than a convention: smoke.tcl reads LICENSE and holds the row to it.

Alternatives considered

  • ISC, the first candidate RELEASING named, and BSD-2-Clause beside it. Both grant the same permissions, both suit rio's POSIX/BSD temperament, and ISC says it in half the words. MIT was taken for recognition: a reader can tell what it permits without reading it, which at a first release is worth more than concision. Between licences that do the same thing, being recognised on sight is the only axis left.
  • Editing the licence text — tightening the wording, dropping the shouted warranty paragraph. Refused: a licence that has been touched is no longer the licence people recognise, which would have cost exactly what MIT was chosen for.
  • Staying unlicensed until v1. This is what the project was doing by omission, and it does not survive contact with a release: the first person handed a copy has no right to keep it.
  • Per-file SPDX headers. Machine-readable, but rio has never carried file headers, and stamping every source in the tree buys something nobody has asked for. Tooling reads the repository-level LICENSE first.
  • A license key in extension manifests. Plausible and forward-compatible by construction (unknown keys are ignored), but it changes the manifest contract and deserves its own record.

Consequences

  • rio may be used, modified, redistributed and sold on, by anyone, provided the copyright notice and licence text travel with the copies. Gate 1's licence half is closed; only CODE_OF_CONDUCT.md remains open there.
  • Contributions arrive under a stated licence, so a patch from a stranger needs no case-by-case question about what rio may do with it.
  • One licence covers the tree only for as long as that stays true. Anything brought in from elsewhere — code, and artwork especially — has to be something rio may pass on, which is the rule ADR-0127 already made a condition of the artwork folder.
  • The About box and LICENSE now say the same thing in two places. That is drift waiting to happen, and it is registered as such: AGENTS.md §7's derived-facts register carries the row, and smoke.tcl is its guard.
  • Nothing in the code depends on the licence, so there is no runtime cost and no new dependency. A licence is not a property a program can enforce; this one is held by review, by the file, and by the one test that reads it.