improve-ts-pkg-architecture

name	improve-ts-pkg-architecture
description	Review architecture for a TypeScript package without nuxt.config.ts. Use for package-native refactors, exports, workspaces, module boundaries, and testability.
effort	high

Improve TS Package Architecture

Surface architectural friction in a TypeScript package (library, CLI, or pnpm monorepo) and propose deepening opportunities — refactors that turn shallow modules into deep ones, using the package's own publishable surface as the seam. The aim is testability and AI-navigability.

Vocabulary, principles, and forbidden patterns live in their canonical files; this file references them. Use the terms in LANGUAGE.md exactly. This skill is informed by the project's domain model (CONTEXT.md, docs/adr/).

Worktree isolation

Before any edit, follow the worktree isolation contract. It provides the atomic live-agent claim used below.

An existing worktree alone does not prove another agent is active.

wt is the only worktree tool. Never run git worktree add, and never use a harness worktree option such as EnterWorktree or isolation: "worktree". Those write to .claude/worktrees/, which is banned. wt places every worktree at <parent>/<repo>.<branch-slug>.

Keep the primary checkout read only. Before mutation, run wt list --format=json. Reuse the task's worktree with wt switch <branch>, or create one with wt switch --create <branch> --base <base>. Read its absolute path from the JSON, then pass that path as workdir to every later command. Never share a mutation worktree between tasks.

Companion files

• LANGUAGE.md — full vocabulary and principles.
• DEEPENING.md — dependency categories, seam ladder (file → subpath export → packages/*), testing strategy.
• TS-PKG-SEAMS.md — catalogue of TS-package-native seams (exports, conditional exports, packages/*, catalogs, bin, hookable, unplugin, citty).
• PKG-CONVENTIONS.md — package conventions (factory shape, options + hooks, error modes, CLI shape, treeshake invariants, fixture layout, runtime portability).
• INTERFACE-DESIGN.md — design-it-twice with parallel sub-agents for chosen candidates.
• code-comments.md — the comment contract for any code this skill writes.

Process

1. Explore

Always run ripast first. Every claim about depth, caller counts, locality, or cross-package leaks must be backed by a ripast invocation; text search misses shadowed identifiers, type-only imports, and re-exports through a subpath. If you cannot cite ripast output, drop the claim.

Pass --tsconfig tsconfig.json (root, or per-package in a monorepo) so subpath aliases and workspace refs resolve. For scan (rg-driven) and noisy tree output, scope with --glob 'src/**,packages/*/src/**,test/**'; trim per project (bin/**, scripts/**, playground/** as needed).

Opening pass — run before forming any candidate:

Command	What it surfaces
npx -y @ripast/cli unused --tsconfig tsconfig.json --exports local	Top-level declarations with zero project references → deletion-test slam-dunks
npx -y @ripast/cli tree --exports exported --tsconfig tsconfig.json	Public surface per file → shallow modules + leaks (anything exported that isn't in the exports map is a confessed private leak)
npx -y @ripast/cli tree --exports local --tsconfig tsconfig.json	Internals per file → locality opportunities

Per-candidate, before listing (scan is rg-driven — use --glob here):

Command	What it surfaces
npx -y @ripast/cli scan <symbol> --glob ...	Caller count + kind classification → drives deletion test + §2 thresholds
npx -y @ripast/cli scan <symbol> --kind identifier-reference,import-specifier --glob ...	Same, minus string-literal noise
npx -y @ripast/cli scan <symbol> --graph mermaid --glob ...	Importer graph → cross-package leaks (graph spanning packages/a/src/ + packages/b/src/ via deep import)

Cite numbers when presenting.

Read the package's published surface first: package.json exports, bin, peerDependencies, sideEffects, engines. The exports map is the contract. Then read CONTEXT.md and docs/adr/ if present.

Orient on the package shape:

• Is this a single-repo library, a CLI (bin field), a plugin (peer-dep on rollup/vite/eslint/etc.), or a pnpm monorepo with packages/*?
• Which TS-package-native seams are already used: subpath exports, conditional exports (types/import/node/browser/workerd), packages/*, catalog: versions, hookable hooks, unplugin/factory shape, citty subcommands, c12 config loading?
• Where does the package hand-roll its own seam (a singleton in a top-level file, a global EventEmitter, a custom plugin registry, ad-hoc env reads) instead of using one the ecosystem provides?

Then use the Agent tool with subagent_type=Explore to walk the codebase. Note friction signals:

• Shallow modules — files re-exporting one function, factories that just new a class, utils that wrap one-liners. Spot via tree --exports exported.
• Bouncing — understanding one feature requires five files with no central seam. scan <symbol> --graph mermaid spanning 10+ directories.
• Pure-function extraction without locality — bugs hide in how the pieces compose (orchestration order, error recovery, cache invalidation).
• Cross-cutting leak — logging/config/error-mapping/telemetry scattered across 10+ files instead of one factory or hook bus.
• Hard-to-test interface — modules reading process.env deep inside, singletons at import, side effects on import.
• Walk PKG-CONVENTIONS.md; each section's "Gap" entry is a friction signal — if present in the codebase, that's a candidate.
• Cross-package leaks (monorepo) — relative or deep imports across workspace packages bypass the exports map. Detect with scan <symbol> --graph mermaid straddling two packages/*. See TS-PKG-SEAMS.md Workspace packages.
• exports map leaks — deep paths (pkg/dist/internal/foo) instead of declared subpaths. Either expose a subpath or stop the leak.
• Cross-module coupling that should flow through a hook bus — two modules importing each other to coordinate, or fan-in to a coordinator module. hookable is the answer. Detect via two-way edges in scan --graph mermaid.
• Treeshake / bundle-size signals — heavy SDK statically imported at module top when only one path uses it. Move the import inside the function, or behind a conditional export. Run npx -y publint && npx -y @arethetypeswrong/cli --pack . plus du -sh dist/.
• Repeated import-time work (regex/schema/table compilation) running whether the module is used or not. Move into a memoised getter inside the factory.

2. Present candidates

Present a numbered list of deepening opportunities. For each candidate:

• Files — which files/modules are involved (include flavour paths: src/index.ts, src/cli.ts, packages/core/src/foo.ts, package.json exports, pnpm-workspace.yaml)
• Problem — why the current architecture is causing friction
• Solution — plain English description of what would change, named in TS-pkg terms (e.g. "collapse these five files into a single createPipeline(opts) factory exported from a new ./pipeline subpath; the existing files become private implementation under src/pipeline/, and the factory exposes a hookable hook bus for the three current extension points")
• Benefits — explained in terms of locality and leverage, and also in how tests would improve (e.g. "the factory can be tested directly with vitest; today the three hooks fire from three different files and the only way to observe them is to import each privately")

Use CONTEXT.md for the domain, LANGUAGE.md for the architecture, TS-PKG-SEAMS.md for the framework seam, and the relevant convention section from PKG-CONVENTIONS.md when the candidate is a convention gap. Example phrasings: "the Order intake module exposed as a ./intake subpath", "establish PKG-CONVENTIONS.md §Hook bus for the build pipeline" — not "the FooBarHandler", not "the Order service".

Reject before listing. Validate caller-count thresholds with scan <symbol> --kind identifier-reference,import-specifier; no guesswork.

• Deletion test fails. Thresholds: subpath export ≥3 consumers or a distinct public concept; workspace packages/* ≥2 independent consumers AND zero coupling back to the host; factory ≥2 callers OR real branching/options; pure value/type mapping ≥4 callers.
• No locality win. Pure-function extraction with no consolidation, speculative seams, defensive re-validation of invariants the caller's types already enforce.
• Renames dressed up as architecture. Note separately or skip.
• Already conventional — matches a PKG-CONVENTIONS.md section.
• Subpath read in exactly one place. Confirm with scan <import-specifier> --kind import-specifier.
• Config threaded through ≥3 layers unchanged — consume at the creation layer or place an adapter at the deepest meaningful seam.
• Contradicts a current ADR without a load-bearing reason. See ADR conflicts below.

Forbidden patterns (always flag, never propose) — full list in PKG-CONVENTIONS.md §"Forbidden patterns".

ADR conflicts: if a candidate contradicts an existing ADR, only surface it when the friction is real enough to warrant revisiting the ADR. Mark it clearly (e.g. "contradicts ADR-0007 — but worth reopening because…"). Don't list every theoretical refactor an ADR forbids.

Do NOT propose interfaces yet. Ask the user: "Which of these would you like to explore?"

3. Grilling loop

Once the user picks a candidate, drop into a grilling conversation. Walk the design tree with them — constraints, dependencies, the shape of the deepened module, what sits behind the seam, what tests survive. For TS-pkg candidates, also walk: which runtimes it must work in (node / browser / workerd / edge / bun), whether it appears in the exports map (and at which subpath / conditional), whether it lives in src/ or a workspace packages/*, what the treeshake / sideEffects story is.

Side effects happen inline as decisions crystallize:

• Naming a deepened module after a concept not in CONTEXT.md? Add the term to CONTEXT.md as a short glossary entry: the term, one sentence of meaning in this codebase, and where it lives. Create the file lazily if it doesn't exist.

• Sharpening a fuzzy term during the conversation? Update CONTEXT.md right there.

• User rejects the candidate with a load-bearing reason? Offer an ADR, framed as: "Want me to record this as an ADR so future architecture reviews don't re-suggest it?" Only offer when the reason would actually be needed by a future explorer to avoid re-suggesting the same thing — skip ephemeral reasons ("not worth it right now") and self-evident ones. Write it to docs/adr/NNNN-slug.md with context, decision, and consequences.

• Want to explore alternative interfaces for the deepened module? See INTERFACE-DESIGN.md. Sub-agents are pre-seeded with TS-pkg-native shapes (single factory, factory + hook bus, subpath-exposed surface, ports & adapters) so the design space is grounded in what the ecosystem already offers.

• Need to know the true blast radius of a rename/move before committing? npx -y @ripast/cli scan <symbol> (counts) or npx -y @ripast/cli scan <symbol> --graph mermaid (importer graph). Quote numbers before promising scope.

• Decision crystallized into a concrete refactor? Execute through ripast, not Edit. Pick the primitive:

  Pass --tsconfig tsconfig.json (or the per-package one) on rename, move, and rename-file so all callers are rewritten.

  Refactor	Command
  Rename a symbol across files	npx -y @ripast/cli rename <from> <to> --tsconfig tsconfig.json --apply (add --scope <file> if multi-declared)
  Move an exported declaration	npx -y @ripast/cli move <symbol> --from <a> --to <b> --tsconfig tsconfig.json --apply
  Move a file (e.g. src/utils/foo.ts → src/pipeline/foo.ts to close a leak)