chore: TypeScript 6 upgrade blocked by @angular/build peer dep ceiling

[corvid-agent]

TypeScript 6 Compatibility — Blocker Report

Evaluated: TypeScript 6.0.3 against the current codebase (2026-04-26)
Current pinned version: ~5.9.3 with overrides lock in package.json
Evaluator: Rook

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tl;dr

The codebase type-checks with 0 errors under TypeScript 6. No source code changes are needed. The upgrade is blocked solely by @angular/build@21.2.7, which declares a peer dependency ceiling of <6.0.

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Type-Check Results

bun x tsc@6 --noEmit --skipLibCheck   # server + shared
# Exit: 0, 0 errors

cd client && bun x tsc@6 --noEmit --skipLibCheck
# Exit: 0, 0 errors

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Dependency Compatibility Matrix

Package	Version	TypeScript peer dep	TS 6.0.3 OK?
@angular/compiler-cli	21.2.9	>=5.9 <6.1	✅
@angular/build	21.2.7	>=5.9 <6.0	❌
@angular/core	21.2.9	(none)	✅
@biomejs/biome	2.4.x	(none)	✅
@types/bun	1.3.12	(none)	✅
@anthropic-ai/claude-agent-sdk	0.2.114	(none)	✅

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Primary Blocker

@angular/build@21.2.7 — peer dep: "typescript": ">=5.9 <6.0"

This package orchestrates the Angular build pipeline (esbuild, Vite, template compilation). The <6.0 ceiling means Angular 21.2.x officially does not support TypeScript 6. Upgrading risks undefined behavior from the build tooling even though type-checking passes.

Note: @angular/compiler-cli (which handles TypeScript compilation) already extends support to <6.1, so the restriction in @angular/build appears conservatively set and may be lifted in a near-term Angular patch.

Secondary Blocker

package.json is a Layer 1 (Structural) protected file. Even once Angular resolves the build tooling constraint, the version bump and override removal require a supermajority council vote + human approval.

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Required Changes (when unblocked)

Changes to package.json (Layer 1 — cannot be applied by automated workflow):

// devDependencies
"typescript": "~6.0.3"   // was "~5.9.3"

// overrides
"typescript": "~6.0.3"   // was "~5.9.3"

No source code changes needed.

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Path Forward

1. Monitor Angular 21.x / 22.x changelog for @angular/build peer dep bump to <6.1
2. Re-run bun x tsc@6 --noEmit --skipLibCheck to confirm still clean
3. Submit council proposal to update package.json (Layer 1 process)

Full evaluation document: docs/typescript-6-evaluation.md on branch agent/rook/evaluate-typescript-6-compatibility-for-moflmmqh-4a5781

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🤖 Agent: Rook | Model: Sonnet 4.6