OpenAI AgentKitFreemium
OpenAI first-party agent toolkit — a visual Agent Builder, embeddable ChatKit UI, a connector registry, and evals, billed at plain API rates.
AI / LLM comparison
OpenAI AgentKit vs Spellbook
Pricing, pros, cons, and ideal use cases — side by side.
SpellbookEnterprise
AI contract review and drafting that lives inside Microsoft Word, where lawyers already work.
At a glance
| OpenAI AgentKit | Spellbook | |
|---|---|---|
| Pricing | FreemiumNo separate platform fee. Agent Builder design is free; you pay standard OpenAI API model and storage rates for execution. As a reference point, GPT-5.2 runs roughly $1.75 per million input tokens and $14 per million output tokens, with GPT-5 mini at about $0.25 per million input tokens. | EnterpriseNot published — 7-day free trial, then per-seat pricing quoted after a demo. Ask about Playbook setup, which is where the value concentrates. |
| Category | AI / LLM | AI / LLM |
| Ideal for | Product teams embedding agents into their own softwareEngineering teams already building on the OpenAI APIStartups that want agent scaffolding without a platform feeTeams standardizing evals alongside agent development | Small and mid-size law firms doing transactional workLean in-house legal teamsCorporate counsel handling high contract volumeFirms standardizing on drafting playbooks |
Pros & cons
OpenAI AgentKit
Pros
- No platform fee on top of API usage
- Visual workflow builder with versioning
- ChatKit ships a production-ready chat UI
- Evals are first-class rather than an afterthought
- Cost model is the API cost model you already forecast
Cons
- Single-provider lock-in at the orchestration layer
- Agent Builder and Connector Registry have been in beta rather than fully GA
- Fewer enterprise governance controls than Copilot Studio or Agentforce
- No managed hosting story comparable to Bedrock AgentCore
Spellbook
Pros
- Works inside Microsoft Word — near-zero workflow change
- Playbooks encode your standards so redlines stay consistent
- Compare benchmarks a deal against market comparables
- Cited answers rather than unsourced summaries
- Free trial available without a sales call
Cons
- No public pricing
- Transactional focus — weak fit for litigation practices
- Playbook quality determines output quality; setup is real work
- Not a legal research platform
Which should you choose?
OpenAI AgentKit is the lighter-weight option (Freemium), while Spellbook sits higher on the pricing ladder (Enterprise). OpenAI AgentKit is built around product teams embedding agents into their own software; Spellbook leans more toward small and mid-size law firms doing transactional work. Shortlist the one whose strengths line up with your biggest constraint.