# newagent.build

Build an AI agent stack layer by layer. Compare 88 components — harness, model, memory, retrieval, security, runtime — and leave with a runnable setup script.

## The ten layers

1. **Harness** (What thinks) — The loop that runs your agent. Take one off the shelf, or skip it and write the loop yourself. 12 options. Required. https://newagent.build/layers/harness
2. **Model provider** (What thinks) — Where the tokens come from. A frontier API, a gateway you control, or your own GPUs. 13 options. Required. https://newagent.build/layers/model
3. **Framework** (What thinks) — The library you write orchestration in, when an off-the-shelf harness is not enough. 8 options. Optional. https://newagent.build/layers/framework
4. **Memory** (What it knows) — What the agent still knows tomorrow. 7 options. Optional. https://newagent.build/layers/memory
5. **Retrieval** (What it knows) — Your own corpus, made searchable. 6 options. Optional. https://newagent.build/layers/retrieval
6. **Web grounding** (What it knows) — Live information from outside your walls, in a shape a model can read. 5 options. Optional. https://newagent.build/layers/search
7. **Tools & integrations** (What it touches) — How the agent acts inside other people's software, and who holds the token when it does. 6 options. Optional. https://newagent.build/layers/tools
8. **Security** (What stops it) — Two halves, and you want both. Guardrails decide what the agent may say and do — injection defence, PII redaction, identity. Containment decides what holds when the guardrails do not: a kernel boundary around code it wrote, a default-deny boundary around everything it can reach. Egress control does not stop prompt injection; it removes the payout. 17 options. Required. https://newagent.build/layers/security
9. **Observability & evals** (How you run it) — Traces of what it did, and a score for whether that was any good. 6 options. Required. https://newagent.build/layers/observability
10. **Runtime & deploy** (How you run it) — Where it runs, and whether it survives a restart. 8 options. Required. https://newagent.build/layers/runtime

## Start here

- Describe what you are building: `GET https://newagent.build/api/advise?q=...`
- Browse everything: https://newagent.build/providers
- Curated stacks: https://newagent.build/stacks
- Guides: https://newagent.build/guides

## Machine interfaces

- `GET https://newagent.build/api/registry` — every component as JSON
- `GET https://newagent.build/api/vendors` — vendors, with the repo and releases feed to watch
- `GET https://newagent.build/api/advise?q=<plain english>` — recommended stack for a description
- `GET https://newagent.build/api/stack?<layer>=<id>&format=sh|json|md|yml|agents|env` — a stack as files
- `GET https://newagent.build/llms.txt` — the whole registry in one fetch

Any page here also returns markdown if you send `Accept: text/markdown`.