AI safety tools for startups

If you are a startup building AI agents, safety is not optional but your budget is tight. You need tools that are free to start, quick to deploy, and do not add operational complexity before you need it. This guide covers what to use and when.

Start with the SDK

The simplest deployment is the Authensor SDK with a YAML policy file. No server, no database, no infrastructure:

pnpm add @authensor/sdk

import { createGuard } from '@authensor/sdk';

const guard = createGuard({ policyPath: './policy.yaml' });

This gives you policy enforcement and receipt generation in your application process. Total cost: zero. Setup time: minutes.

What your first policy should look like

Start with a deny-by-default policy that explicitly allows the tools your agent needs:

version: "1"
rules:
  - tool: "search.web"
    action: allow
  - tool: "file.read"
    action: allow
    when:
      args.path:
        startsWith: "/data/"
  - tool: "*"
    action: block
    reason: "Not in allowlist"

This is your minimum viable safety. It takes five minutes to write and prevents the most dangerous failure modes.

Add content scanning early

Prompt injection is not a theoretical risk. Add Aegis as soon as you have users:

pnpm add @authensor/aegis

const guard = createGuard({
  policyPath: './policy.yaml',
  aegis: { enabled: true },
});

Aegis has zero dependencies and runs in-process. No additional infrastructure needed.

Scale up when you need to

As you grow, add capabilities in order of need:

1. SDK + policy file: Day one. Free, embedded.
2. Aegis scanning: When you have users. Still free, embedded.
3. Approval workflows: When your agent does consequential things (sends emails, makes payments).
4. Sentinel monitoring: When you have enough traffic for behavioral baselines to be meaningful.
5. Control plane: When you need centralized policy management, multi-tenant support, or API-based receipt queries.

Cost model

The entire Authensor stack is MIT-licensed open source. The cost is your infrastructure:

• SDK + Aegis + Sentinel: Zero (runs in your application process)
• Control plane: One small server + PostgreSQL (the same database you are probably already running)

Compare this to managed services that charge per API call. At 10,000 agent actions per day, managed services can cost hundreds of dollars per month. Authensor costs the same whether you process 10 or 10 million actions.

Investor and customer conversations

"How do you handle AI safety?" is a question investors and enterprise customers ask. Having Authensor deployed lets you answer with specifics: policy enforcement, audit trails, content scanning, and approval workflows. This is more convincing than "we use system prompt instructions."

Do not wait

The worst time to add safety tooling is after an incident. The best time is now, before your agent has access to production data and real users. Start with the SDK and a simple policy. Expand from there.