Summary
Assessed migrating typescript ^6.0.3 → 7.0.2 across all four workspace packages (2026-08-25). Deferred. The codebase itself is TS7-ready — typecheck, lint, and tests all pass under 7.0.2 — but declaration emit is hard-blocked by the toolchain: TypeScript 7 ships no programmatic compiler API, and tsup's d.ts pipeline requires one.
What already works on 7.0.2 (verified locally)
pnpm -r typecheck (tsc --noEmit, native Go compiler): clean on all four packages. The existing ignoreDeprecations: "6.0" in tsconfig.base.json is accepted without error.pnpm -r test: all pass (vitest transforms via esbuild; no TS-API dependency at test time).pnpm check (oxfmt + oxlint + typecheck): clean.
Blocker: d.ts emit
All three published packages (@coder/ai-sdk-agent, @coder/ai-sdk-provider, @coder/ai-sdk-sandbox) build with tsup dts: true. tsup 8.5.1 (the latest release) bundles rollup-plugin-dts@6.1.1, which consumes the TypeScript JS compiler API (ts.sys, ts.createProgram, ...).
typescript@7.0.2 is the native (Go) compiler: main: null, per-platform binary deps, only ./unstable/* JS exports, and no stable programmatic API — that is targeted for TS 7.1. With 7.0.2 installed, every package's build dies at DTS:
TypeError: Cannot read properties of undefined (reading 'useCaseSensitiveFileNames')
at node_modules/.pnpm/rollup-plugin-dts@6.1.1_rollup@4.53.2_typescript@5.7.3/node_modules/rollup-plugin-dts/dist/rollup-plugin-dts.cjs
(bundled into tsup/dist/rollup.js)
Options considered and rejected (for now)
- tsup
experimentalDts (@microsoft/api-extractor): different declaration-bundling pipeline → would change the published d.ts output for no functional gain, and api-extractor is likewise built on the JS compiler API.
- Alias
typescript → npm:@typescript/typescript6: gives tsup a working API but makes tsc TS6 again — defeats the purpose.
- Split toolchain (TS7 for typecheck, TS6 for emit): two TS majors in devDependencies plus checker/emitter divergence risk; the repo-wide typecheck already completes in ~1s, so the payoff does not cover the complexity.
- Replace tsup dts with raw
tsc emit + separate d.ts bundler: restructures the build and changes the published declaration layout (single bundled index.d.ts today).
Ecosystem readiness
- Standalone
rollup-plugin-dts (latest) already declares typescript ^4.5 || ^5 || ^6 || ^7 alongside a @typescript/typescript6 peer — the compat path tooling is converging on — but tsup vendors its own older copy and has not shipped that support.
- Upstream
vercel/ai (the ai v7 ecosystem we target) still builds with typescript 5.8.3.
Re-check criteria — re-assess when any of these lands
- tsup releases a version > 8.5.1 whose dts pipeline supports TS7 (updated
rollup-plugin-dts with the @typescript/typescript6 compat peer, or a pipeline built on the stable TS 7.1 API).
- TypeScript 7.1 ships the stable programmatic API and tsup/rollup-plugin-dts adopt it.
- Ecosystem signal:
vercel/ai moves its toolchain to TS 6/7.
Retry procedure: bump typescript to ^7.x in all four packages → pnpm install → pnpm check && pnpm -r build && pnpm -r test → diff dist/*.d.ts of all three published packages against a TS6 baseline (published type surface must be unchanged) → live e2e → PR per AGENTS.md merge protocol.
Generated with mux • Model: anthropic:claude-fable-5 • Thinking: xhigh
Summary
Assessed migrating
typescript^6.0.3→7.0.2across all four workspace packages (2026-08-25). Deferred. The codebase itself is TS7-ready — typecheck, lint, and tests all pass under 7.0.2 — but declaration emit is hard-blocked by the toolchain: TypeScript 7 ships no programmatic compiler API, and tsup's d.ts pipeline requires one.What already works on 7.0.2 (verified locally)
pnpm -r typecheck(tsc --noEmit, native Go compiler): clean on all four packages. The existingignoreDeprecations: "6.0"intsconfig.base.jsonis accepted without error.pnpm -r test: all pass (vitest transforms via esbuild; no TS-API dependency at test time).pnpm check(oxfmt + oxlint + typecheck): clean.Blocker: d.ts emit
All three published packages (
@coder/ai-sdk-agent,@coder/ai-sdk-provider,@coder/ai-sdk-sandbox) build with tsupdts: true. tsup 8.5.1 (the latest release) bundlesrollup-plugin-dts@6.1.1, which consumes the TypeScript JS compiler API (ts.sys,ts.createProgram, ...).typescript@7.0.2is the native (Go) compiler:main: null, per-platform binary deps, only./unstable/*JS exports, and no stable programmatic API — that is targeted for TS 7.1. With 7.0.2 installed, every package's build dies at DTS:Options considered and rejected (for now)
experimentalDts(@microsoft/api-extractor): different declaration-bundling pipeline → would change the published d.ts output for no functional gain, and api-extractor is likewise built on the JS compiler API.typescript→npm:@typescript/typescript6: gives tsup a working API but makestscTS6 again — defeats the purpose.tscemit + separate d.ts bundler: restructures the build and changes the published declaration layout (single bundledindex.d.tstoday).Ecosystem readiness
rollup-plugin-dts(latest) already declarestypescript ^4.5 || ^5 || ^6 || ^7alongside a@typescript/typescript6peer — the compat path tooling is converging on — but tsup vendors its own older copy and has not shipped that support.vercel/ai(theaiv7 ecosystem we target) still builds with typescript5.8.3.Re-check criteria — re-assess when any of these lands
rollup-plugin-dtswith the@typescript/typescript6compat peer, or a pipeline built on the stable TS 7.1 API).vercel/aimoves its toolchain to TS 6/7.Retry procedure: bump
typescriptto^7.xin all four packages →pnpm install→pnpm check && pnpm -r build && pnpm -r test→ diffdist/*.d.tsof all three published packages against a TS6 baseline (published type surface must be unchanged) → live e2e → PR per AGENTS.md merge protocol.Generated with
mux• Model:anthropic:claude-fable-5• Thinking:xhigh