diff --git a/mise.toml b/mise.toml
index 6dd983f6..ac982c7f 100644
--- a/mise.toml
+++ b/mise.toml
@@ -1,57 +1,108 @@
+# SPDX-License-Identifier: CC-BY-SA-4.0
+#
+# Every entry below was checked against `mise registry` before being written.
+# The previous version named 13 tools that do not exist in the registry, so
+# mise emitted ~25 lines of warnings on EVERY shell entry in this repo while
+# installing none of them.
+
 [tools]
-# Language runtimes
+# ---------------------------------------------------------------------------
+# Primary languages for this repo.
+#
+# erlang + elixir were MISSING entirely, despite Elixir being the language of
+# lib/ and the 71 test files. Pinned to the same versions .github/workflows/
+# tests.yml gives erlef/setup-beam, so a local `mix test` runs on the same
+# toolchain as CI rather than on whatever the developer happens to have.
+# ---------------------------------------------------------------------------
+erlang = "27.0"
+elixir = "1.17"
+rust = "latest"
+zig = "latest"
+
+# ---------------------------------------------------------------------------
+# Secondary runtimes retained from the previous file.
+# ---------------------------------------------------------------------------
 node = "latest"
 python = "latest"
-rust = "latest"
 go = "latest"
-zig = "latest"
 java = "latest"
 bun = "latest"
-denojs = "latest"
+deno = "latest"   # was `denojs` — not a registry name
 
-# Package managers
+# ---------------------------------------------------------------------------
+# Package managers / task runner
+# ---------------------------------------------------------------------------
 npm = "latest"
 yarn = "latest"
 pnpm = "latest"
-pip = "latest"
-cargo = "latest"
-go-task = "latest"
+just = "latest"   # the actual task runner for this repo (see Justfile)
 
-# Formatting & Linting
-gofmt = "latest"
+# ---------------------------------------------------------------------------
+# Formatting & linting
+# ---------------------------------------------------------------------------
 black = "latest"
-isort = "latest"
 ruff = "latest"
 prettier = "latest"
 shfmt = "latest"
 stylua = "latest"
 
+# ---------------------------------------------------------------------------
 # Build tools
+# ---------------------------------------------------------------------------
 cmake = "latest"
 make = "latest"
 ninja = "latest"
 
-# Shell tools
-git = "latest"
-gnu-sed = "latest"
-gnu-tar = "latest"
-gnu-grep = "latest"
-
-# Testing
-vitest = "latest"
-pytest = "latest"
-jest = "latest"
+# ---------------------------------------------------------------------------
+# REMOVED — none of these resolve in the mise registry, so they installed
+# nothing and only produced warnings. Grouped by why they were wrong:
+#
+#   Already provided by a tool that IS listed above:
+#     cargo   -> ships with `rust`
+#     gofmt   -> ships with `go`
+#     pip     -> ships with `python`
+#
+#   Project-level dependencies, not system tools. These belong in
+#   package.json / pyproject.toml / mix.exs, not in a toolchain manager:
+#     vitest, jest, pytest, isort
+#
+#   Task runner that never installed:
+#     go-task -> not a registry name. NB the bare name `task` does not work
+#     either: `mise registry` LISTS it as `aqua:go-task/task`, but resolving
+#     `task@latest` still fails. Appearing in `mise registry` output is not
+#     sufficient to conclude a name resolves — check with `mise ls-remote`.
+#     Dropped entirely; this repo drives everything through the Justfile, so
+#     `just` is listed above instead.
+#
+#   Base system binaries that mise should not be shadowing on Linux:
+#     git, gnu-sed, gnu-grep, gnu-tar
+#
+# If a GNU-vs-BSD coreutils difference ever actually bites on macOS, add
+# `coreutils` (which does exist in the registry) rather than these names.
+# ---------------------------------------------------------------------------
 
 [env]
-# Common environment variables
 NODE_ENV = "development"
 PYTHONDONTWRITEBYTECODE = "1"
 PYTHONUNBUFFERED = "1"
 
-# Task runner alias
-[alias]
-task = "go-task"
-build = "cargo build --release || npm run build || go build"
-test = "cargo test || npm test || go test ./..."
-lint = "ruff check . || prettier --check . || black --check ."
-fmt = "ruff format . || prettier --write . || black ."
+# ---------------------------------------------------------------------------
+# REMOVED — an `[alias]` section holding what were clearly meant to be tasks:
+#
+#     [alias]
+#     task  = "go-task"
+#     build = "cargo build --release || npm run build || go build"
+#     test  = "cargo test || npm test || go test ./..."
+#     lint  = "ruff check . || prettier --check . || black --check ."
+#     fmt   = "ruff format . || prettier --write . || black ."
+#
+# mise's `[alias]` maps an alias to a TOOL PLUGIN — it does not define tasks,
+# so none of these ever ran. mise also warns that `[alias]` is deprecated in
+# favour of `[tool_alias]`.
+#
+# They are not re-added as `[tasks]`, because the Justfile already defines
+# `build`, `test`, `fmt`, `fmt-check`, `lint`, `doctor` and `heal` properly and
+# for the languages this repo actually uses. Two competing task runners with
+# the same verb names — one of which silently falls through `||` chains to a
+# different language's build — is worse than one. Use `just <recipe>`.
+# ---------------------------------------------------------------------------