agent-starter

Anthropic's own engineering patterns, extracted from the Claude Code CLI source leak and packaged into reusable skills, templates, and guides for bootstrapping AI-agent-friendly projects.

Usage

Point an AI agent at this repo and say "read this repo and set up my project" — the agent reads AGENT.md and scaffolds a complete project interactively.

Or install the /new-project skill once and run it in any session:

npx skills add sneg55/agent-starter -a claude-code -g

Then: /new-project

Guides

guides/large-codebase-best-practices.md

Comprehensive best practices for setting up and scaling a large codebase with Claude Code — directory structure, file size targets, naming conventions, error handling, CLAUDE.md hierarchy, and more. All derived from analyzing Anthropic's own Claude Code CLI source.

guides/lint-rules-for-ai.md

Tiered Biome + ESLint ruleset tuned for AI-agent-driven TypeScript codebases. Blocks the specific mistakes LLMs make (dropped awaits, any escape hatches, hallucinated imports, half-finished functions) rather than enforcing arbitrary line caps. Biome handles fast syntactic rules + formatting; ESLint keeps type-aware and plugin-specific rules. Pairs with templates/biome.json, templates/eslint.config.mjs, and hooks/lint-on-edit.sh.

guides/hooks-reference.md

Complete reference for Claude Code's hook system — all 4 hook types, all 27 events, exit code behavior, configuration format, and 10 practical examples (auto-lint, block dangerous commands, agent verification, security review, Slack notifications, and more).

guides/tool-authoring-pattern.md

The BashTool/-style directory-per-tool layout extracted from Claude Code's own source. Each tool is a handful of single-purpose files (toolName.ts, schema.ts, prompt.ts, validation.ts, permissions.ts, security.ts, execute.ts, result.ts). Gives an agent a predictable place to look when editing any tool and breaks whole classes of import cycles.

guides/error-id-registry.md

Every thrown error carries a stable ID (E_CFG_003) from a central registry. Logs, telemetry, docs, and agents all reference the same ID, so error-message rewordings don't break grep or alerting. Pairs with templates/errorIds.ts.

guides/discriminated-union-results.md

Result<Ok, Err> as the one shape every fallible function returns. Exhaustiveness-checked via the compiler; no ad-hoc {success, data} / {ok: 1} drift across edits. Reserves throws for programmer errors only.

guides/abort-signal-threading.md

Thread AbortSignal through every long-running call so Ctrl+C, timeouts, and obsoleted work actually stop. Covers the canonical entry-point shape, AbortSignal.any for composed timeouts, the AbortError swallow anti-pattern, and an ESLint rule idea for bare fetch().

guides/prompt-caching.md

How to structure prompts so Anthropic's prefix cache hits 80%+. Canonical order (system → tools → stable context → history → user turn), the cache breakpoint layout, silent cache-breakers (timestamps, unstable JSON key order, per-user strings in the prefix), and TTL-aware polling intervals.

guides/zod-at-the-boundary.md

Validate external data the moment it enters your program; never re-check inside. The schema is the source of truth for the type (type T = z.infer<typeof schema>). Covers env vars, config files, HTTP responses, and LLM output. Pairs with templates/env.ts.

Templates

templates/NEW_PROJECT_PROMPT.md

Copy-paste prompt for Claude Code to scaffold a new project from scratch. Covers directory structure, CLAUDE.md hierarchy, modular rules, error handling, constants, env validation, git setup, and coding standards. Just fill in the {{placeholders}} and go.

templates/biome.json + templates/eslint.config.mjs

Drop-in Biome + ESLint configs tuned for AI-agent TypeScript projects. Biome owns formatting and fast syntactic rules; ESLint owns type-aware correctness (no-floating-promises, the no-unsafe-* family), import resolution (catches hallucinated modules), sonarjs cognitive complexity, and security rules. See guides/lint-rules-for-ai.md for the rationale and the full split.

templates/CLAUDE.md

Drop-in project instructions template with the full 4-type memory taxonomy (user, feedback, project, reference), memory file format, consolidation workflow, recall guidelines, and git safety rules.

templates/errorIds.ts

Central error ID registry + AppError class. Every throw site references a stable E_DOMAIN_NNN ID that stays searchable even as messages get rewritten. Pairs with guides/error-id-registry.md.

templates/truncate-for-context.ts

Head-plus-tail truncator for tool output. Keeps the first N lines and last M lines, replaces the middle with [... X lines elided ...]. Pipe every tool result through this so cat large.log and npm test don't blow the context window.

templates/env.ts

Single env-var boundary. All process.env reads happen here and nowhere else (the ESLint config enforces this). Zod schema is the source of truth for the Env type; invalid env fails loudly at startup with the exact field and reason. Pairs with guides/zod-at-the-boundary.md.

Usage:

# Option A: paste the prompt into Claude Code for a new project
cat templates/NEW_PROJECT_PROMPT.md

# Option B: drop the CLAUDE.md template into an existing project
cp templates/CLAUDE.md /path/to/your/project/CLAUDE.md

Skills

Install all skills globally with npx skills:

npx skills add sneg55/agent-starter -a claude-code -g

/simplify

Code review and cleanup — spawns 3 parallel agents (Code Reuse, Quality, Efficiency) to review your git diff and fix issues.

/remember

Memory review and organization — scans auto-memory entries and proposes promotions to CLAUDE.md, CLAUDE.local.md, or shared memory. Detects duplicates, outdated entries, and conflicts.

/commit

Create a single well-crafted git commit. Analyzes diff, follows repo's commit style, writes a "why not what" message. Includes Git Safety Protocol.

/commit-push-pr

Full git workflow — creates branch, commits, pushes, and creates/updates a PR with summary and test plan. Detects existing PRs and updates them.

/dream

Memory consolidation — reflective pass that merges, prunes, and re-indexes memory files. Run periodically to keep memories organized. Works through 4 phases: orient, gather, consolidate, prune.

/new-project

Full project bootstrap — interviews the developer (name, description, stack, components), then scaffolds directory structure, CLAUDE.md, config files, hooks, skills, and first commit. Mirrors AGENT.md.

Memory Taxonomy

The template uses a 4-type memory system:

Key principles:

• Never save what's derivable from code/git
• Convert relative dates to absolute
• Structure feedback with Why + How to apply
• Verify memories against current state before acting on them