Which SKU do I need?

The @pleach/* surface is 14 published packages (plus @pleach/observe in alpha and the reserved @pleach/trust-pack). Most projects need three or four. The packages are branches grafted onto one lattice — pick the branches that carry weight for what you're building, leave the rest for later. This page maps what you're building to the shortest install list, plus a one-line reason for each. If you're not sure, start with the first row — @pleach/core alone covers more cases than you'd guess.

The shortest answer

The recipes column on the right is the canonical worked example for each row. Most of them are under 100 lines of glue over @pleach/core.

Shortcuts by shape

If "what are you building?" is too narrow a question, here are seven common shapes the runtime is built around. Each maps to a recipe in @pleach/recipes and a SKU bundle.

SaaS adding a chat tab

A typical multi-tenant web app that wants a chatbot tab. You own your auth, your DB, your billing. Add Pleach without touching any of them.

Install: @pleach/core, @pleach/react Recipe: simpleChatbot Reach for next: @pleach/observe (alpha) once you want per-tenant cost rollup.

Vertical agent (specific tools, specific knowledge)

You're shipping an agent for a specific domain — legal review, medical coding, ops triage — with a curated tool set and a knowledge base. Not generic ChatGPT-shaped.

Install: @pleach/core, @pleach/base-tools, @pleach/tools Recipe: verticalAgent

Compliance-bound (regulated industry)

HIPAA, GDPR, PCI-DSS, SOC 2. You need scrubbers on inbound content, audit attestation on every call, and a hash chain you can prove to a regulator.

Install: @pleach/core, @pleach/compliance, @pleach/compliance-contract Recipe: compliantChatbot Reach for next: @pleach/replay once you need chain-verifier attestation.

On an existing Anthropic / OpenAI Enterprise contract

You already have an Anthropic Enterprise or OpenAI Enterprise contract — SSO, ZDR, Workspaces / Projects. You want per-axis cost rollup inside one Workspace without a new vendor.

Install: @pleach/core, @pleach/gateway (+ @pleach/observe, alpha) Recipe: enterpriseAgent Read first: Migrating from Anthropic Enterprise or Migrating from OpenAI Enterprise.

Multi-tenant platform (per-customer BYOK + billing)

You're running multiple customer agents on the same substrate, with per-customer BYOK, per-customer policies, and per-customer billing.

Install: @pleach/core, @pleach/gateway, @pleach/compliance Recipe: enterpriseAgent

• Multi-tenant SaaS agent.

Subagent swarm (bounded fan-out under a root turn)

A root agent that spawns N specialist sub-agents and reconciles their answers, with a per-root-turn cost ceiling. Common shape for research, planning, and refactor agents.

Install: @pleach/core, @pleach/recipes Recipe: subagentSwarm

Regression-grade eval lab

You want fixture-driven eval against the audit log with replay determinism and Welch t-test scoring. CI-runnable, not notebook-shaped.

Install: @pleach/core, @pleach/eval, @pleach/replay Recipe: evalLab

When you don't need a sibling SKU

@pleach/core already ships these in the substrate; you don't need a sibling for them:

• Session lifecycle, channels, checkpointing. Built-in.
• Storage adapters (Memory / IndexedDB / Supabase). Built-in.
• Family-lock, model resolution matrix, transport selection. Built-in.
• AuditableCall row + event log + hash chain (schema-side). Built-in. The verifier ships in @pleach/replay.
• OpenTelemetry spans (session.turn, llm.invocation, etc.). Built-in. @pleach/observe (alpha, not yet on npm) adds destination plugs (Postgres, Supabase, Pleach Hosted); core ships the OTel emission.
• Plugin contract. Built-in. Authoring conventions in Plugin authoring standards.
• The four-stage lattice + singleton synthesize seam. Built-in invariants enforced by lint on the core repo.

Quick "do I install this?" gut-checks

A few SKUs get asked about more than others. Short answers:

• @pleach/base-tools — install if you want a working agent today and you don't have a domain tool set yet. Ships math, datetime, scratchpad, unit_convert, text_search, opt-in url_fetch.
• @pleach/tools — install if you're authoring tool definitions. Provides the contract + Zod helpers + queryable registry. Skip if you're using @pleach/base-tools directly.
• @pleach/sandbox — install if you're running untrusted code (coding agent, user-supplied scripts). Contract today; vendor adapters land under @pleach/sandbox-<vendor>.
• @pleach/recipes — install if you want high-level factories (simpleChatbot, ragChatbot, compliantChatbot, verticalAgent, subagentSwarm, enterpriseAgent) instead of wiring SessionRuntime from scratch.
• @pleach/trust-pack — reserved name. Not shipping code today. Don't install.

Where to go next