5 files changed, 48 insertions, 3 deletions

diff --git a/openspec/changes/fix-mason-installer-deps/.openspec.yaml b/openspec/changes/archive/2026-09-21-fix-mason-installer-deps/.openspec.yaml
index 563fab5..563fab5 100644
--- a/openspec/changes/fix-mason-installer-deps/.openspec.yaml
+++ b/openspec/changes/archive/2026-09-21-fix-mason-installer-deps/.openspec.yaml
diff --git a/openspec/changes/fix-mason-installer-deps/proposal.md b/openspec/changes/archive/2026-09-21-fix-mason-installer-deps/proposal.md
index 5734f55..5734f55 100644
--- a/openspec/changes/fix-mason-installer-deps/proposal.md
+++ b/openspec/changes/archive/2026-09-21-fix-mason-installer-deps/proposal.md
diff --git a/openspec/changes/fix-mason-installer-deps/specs/editor-toolchain/spec.md b/openspec/changes/archive/2026-09-21-fix-mason-installer-deps/specs/editor-toolchain/spec.md
index 8298fbd..8298fbd 100644
--- a/openspec/changes/fix-mason-installer-deps/specs/editor-toolchain/spec.md
+++ b/openspec/changes/archive/2026-09-21-fix-mason-installer-deps/specs/editor-toolchain/spec.md
diff --git a/openspec/changes/fix-mason-installer-deps/tasks.md b/openspec/changes/archive/2026-09-21-fix-mason-installer-deps/tasks.md
index 2d2d259..2829440 100644
--- a/openspec/changes/fix-mason-installer-deps/tasks.md
+++ b/openspec/changes/archive/2026-09-21-fix-mason-installer-deps/tasks.md
@@ -4,15 +4,15 @@
       existing `home.packages` list (alongside `tree-sitter`/`stdenv.cc`), with a
       short comment noting they're required by `mason.nvim`'s installers; verify by
       reading the file back and confirming the three entries are present.
-- [ ] 1.2 Verify the flake still evaluates: run `nix flake check` and confirm it
+- [x] 1.2 Verify the flake still evaluates: run `nix flake check` and confirm it
       succeeds.
 
 ## 2. Verify Mason installs succeed
 
-- [ ] 2.1 Apply the profile on an affected host (`home-manager switch --flake
+- [x] 2.1 Apply the profile on an affected host (`home-manager switch --flake
       .#tom@linux` or `.#tom@darwin`, whichever is reachable) and confirm the
       activation completes without error.
-- [ ] 2.2 In Neovim, delete `~/.local/state/nvim/mason.log` (or run `:MasonUninstallAll`
+- [x] 2.2 In Neovim, delete `~/.local/state/nvim/mason.log` (or run `:MasonUninstallAll`
       then reinstall), trigger installation of the previously-failing packages
       (`pyright`, `bash-language-server`, `debugpy`, `terraform-ls`,
       `yaml-language-server`, `typescript-language-server`, `css-lsp`, `html-lsp`),
diff --git a/openspec/specs/editor-toolchain/spec.md b/openspec/specs/editor-toolchain/spec.md
new file mode 100644
index 0000000..8320e61
--- /dev/null
+++ b/openspec/specs/editor-toolchain/spec.md
@@ -0,0 +1,45 @@
+# editor-toolchain Specification
+
+## Purpose
+
+Provisions, via the shared home-manager profile, the runtime toolchain that the
+externally Stow-managed Neovim/mason.nvim config depends on to install and run LSP
+servers, formatters, and debug adapters — without home-manager owning that editor
+config itself.
+
+## Requirements
+
+### Requirement: mason.nvim installer dependencies are provisioned
+The shared home-manager profile SHALL include a Node.js runtime (providing `npm`), a
+Python 3 interpreter (providing `python3`), and `unzip` on `PATH`, so that
+`mason.nvim`'s package installers can locate the tools they shell out to.
+
+#### Scenario: npm-based Mason package installs successfully
+- **WHEN** the shared home profile is activated and `mason.nvim` installs an
+  npm-based package (for example an LSP server distributed via npm)
+- **THEN** `mason.nvim`'s installer finds `npm` on `PATH` and the installation does
+  not fail with an `ENOENT`/"could not find executable" error for `npm`
+
+#### Scenario: Python-based Mason package installs successfully
+- **WHEN** the shared home profile is activated and `mason.nvim` installs a
+  Python-based package (for example `debugpy`)
+- **THEN** `mason.nvim`'s installer finds a `python3` interpreter on `PATH` and the
+  installation does not fail with a "no python3 installation found" error
+
+#### Scenario: Archive-based Mason package installs successfully
+- **WHEN** the shared home profile is activated and `mason.nvim` installs a package
+  distributed as a zip archive (for example `terraform-ls`)
+- **THEN** `mason.nvim`'s installer finds `unzip` on `PATH` and the installation does
+  not fail with an `ENOENT`/"could not find executable" error for `unzip`
+
+### Requirement: Editor toolchain packages do not manage editor configuration
+Packages provisioned by this capability SHALL supply only the underlying
+interpreters/tools that the externally-managed Neovim dotfiles config depends on;
+this capability SHALL NOT generate, own, or otherwise manage any Neovim
+configuration file (for example `init.lua` or plugin/LSP configuration).
+
+#### Scenario: No competing Neovim configuration is generated
+- **WHEN** the shared home profile provisions the editor toolchain packages
+- **THEN** no Neovim configuration file is created or managed by this capability —
+  the externally Stow-managed dotfiles config remains the sole owner of that
+  configuration