4ebcec7750
Phase 3 of epic #4636, stages 1-2. Implements ADR-4650 decisions 1 and 2: one containment predicate, and an exported shape that cannot hand a caller a usable path when the answer is unsafe. THE EXPORT IS NOW A PAIR, BOTH RETURNING A BRANDED TYPE: assertWithinRoot(candidate, root, label?, opts?) -> ContainedPath (throws) tryWithinRoot(candidate, root, opts?) -> ContainedPath | null ADR-4650 names only the throwing form. That does not survive contact with the call sites: findPhaseArtifact probes a direct path, then a .planning/ path, then each readdir entry, and throwing on the first miss breaks it outright. Six of the fifteen sites need a non-throwing check. Recorded here rather than papered over. WHY BRANDED. validatePath returns { safe, resolved, error } and populates resolved with the ESCAPING path on the traversal branch — so a caller who skips the boolean gets an attacker-controlled value precisely in the dangerous case. tryWithinRoot returns exactly null there; assertWithinRoot throws. A plain string is not assignable to ContainedPath, so a migrated site that validates one path and then passes a different one is now a type error rather than a silent bug. That is the defect this epic exists to close, and I introduced it twice in Phase 2. THE ENGINE IS UNTOUCHED. validatePath's body is not re-derived — the diff shows zero edits to the dangling-symlink existence-oracle closure, the ancestor canonicalization (macOS /var vs /private/var), or the separator-aware boundary test. Each was acquired as a bug fix and a re-derivation would silently lose one. requireSafePath now delegates to assertWithinRoot, so there is one implementation beneath both names; its return type is branded, which is why its 13 call sites compile unchanged. A TYPESCRIPT LIMITATION, FIXED AT THE ROOT RATHER THAN WORKED AROUND. TS applies never-return control-flow narrowing only when the callee is a function declaration or a const with an EXPLICIT type annotation. Both routers do `const { error } = io` — destructured, unannotated — so `error(...)` did not narrow ContainedPath | null and four sites wanted a dead `throw new Error('unreachable')` after it. Annotating the const (`const error: typeof io.error = io.error`) makes TS narrow properly and the dead throws are gone. That annotation has a large, deliberate consequence: with narrowing working, `@typescript-eslint/no-unnecessary-type-assertion` fires at 37 sites in commands.cts where `as string` / `!` existed ONLY to paper over the missing narrowing. They are removed. The rule is type-aware and fires only where the assertion changes nothing, and both forms erase at compile time, so the emitted behavior is unchanged — but the module loses 37 unchecked casts over string | undefined, which is the same class of "trust me" the containment work is removing. Widening the diff here buys that. TWO SITES LOSE DIAGNOSTIC TEXT, deliberately. tryWithinRoot has no error channel, so init.cts's agent-skills warning and cmdPrSubrepo's rejection now name the condition rather than echoing validatePath's message. verify.cts had already stopped echoing it on purpose — the message embeds absolute host paths — so this makes the three agree instead of two-of-three. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
GSD Core
Git. Ship. Done.
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A light-weight meta-prompting, context engineering, and spec-driven development system for Claude Code, OpenCode, Antigravity CLI, Kimi CLI, Kilo, Codex, Copilot, Cursor, Windsurf, and more.
What is GSD Core
GSD Core is a context-engineering and spec-driven development framework that drives AI coding agents (Claude Code, Codex, Antigravity CLI, Kimi CLI, Copilot, Cursor, and more) through a disciplined phase loop. It solves context rot — the quality degradation that accumulates as an AI fills its context window — by running all heavy research, planning, and execution work in fresh-context subagents while keeping your main session lean.
How it works
Each milestone repeats the same five-step loop, one phase at a time:
- Discuss — capture implementation decisions before anything is planned
- Plan — research, decompose, and verify the plan fits a fresh context window
- Execute — run plans in parallel waves; each executor starts with a clean 200k-token context
- Verify — walk through what was built; diagnose and fix before declaring done
- Ship — create the PR, archive the phase, repeat for the next one
Quickstart
npx @opengsd/gsd-core@latest
The installer prompts for your runtime (Claude Code, OpenCode, Antigravity CLI, Kimi CLI, Kilo, Codex, Copilot, Cursor, Windsurf, and more) and whether to install globally or locally. The installer is required for cross-runtime compatibility — do not copy files from agents/ or commands/ directly.
On another runtime or without Node.js? See Install on your runtime.
Once installed, start a new project or onboard an existing repo:
/gsd-new-project # greenfield project
/gsd-onboard # existing codebase
New here? Follow Your first project for a guided walkthrough from install to first shipped phase, or Onboarding an existing codebase for brownfield setup.
Documentation
What's new in 1.7.0 → docs/whats-new-1.7.0.md
Tutorials — learning by doing:
How-to guides — task-focused recipes:
Reference — authoritative facts:
Explanation — concepts and design decisions:
Full index: docs/README.md. Other languages: 日本語 · 한국어 · Português · 简体中文.
Why it works
Most AI-coding setups fail at scale because context bloat silently degrades output quality, there is no shared memory between sessions, and nothing verifies that code actually works. GSD Core solves all three: heavy work runs in fresh subagents, structured artifacts like STATE.md and CONTEXT.md survive session boundaries, and the verify step walks through what was built and generates fix plans before a phase is declared done. See docs/explanation/context-engineering.md for the full reasoning.
Troubleshooting? See docs/how-to/recover-and-troubleshoot.md.
Community
| Project | Platform |
|---|---|
| gsd-opencode | Original OpenCode port |
| Discord | Community support |
Star History
License
MIT License. See LICENSE for details.
Claude Code is powerful. GSD Core makes it reliable.