OpenAI Agents SDK vs Claude Agent SDK for Developers: A Complete 2026 Comparison
Both SDKs are free to use as orchestration layers — you pay only for the underlying model tokens. OpenAI's entry model GPT-6 Luna costs $0.10 per 1M input tokens and $0.50 per 1M output tokens, while Anthropic's cheapest agent-capable API model, Haiku 4.5, runs $1/$5 per 1M tokens, making OpenAI roughly 10x cheaper at the entry tier; OpenAI's flagship GPT-6 Astra ($10/$50) prices identically to Anthropic's Fable 5.1 ($10/$50). Choose the OpenAI Agents SDK if minimizing token spend and using built-in hosted tools like web search ($10 per 1,000 calls) matters most; choose the Claude Agent SDK if you're already on a Claude Max or Team plan, which include monthly API credits ($100–$200) that cover the SDK.
TL;DR
- Neither SDK charges its own fee — OpenAI states the Responses API and Agents SDK are 'not charged separately,' and Anthropic covers the Claude Agent SDK under its normal API billing and subscription credits.
- Entry-level token costs favor OpenAI: GPT-6 Luna runs $0.10 input / $0.50 output per 1M tokens, versus Haiku 4.5 at $1/$5 on the Anthropic side.
- Flagship pricing is identical: OpenAI's GPT-6 Astra and Anthropic's Fable 5.1 both cost $10 input / $50 output per 1M tokens (short context).
- OpenAI charges a long-context tier above 272,000 input tokens at roughly double rates; Anthropic and Google do not charge a long-context tier.
- Claude Max 5x and Max 20x plans include $100 and $200 in monthly API credits respectively, and Team plans pool up to $500/month — credits cover the Claude Agent SDK.
- OpenAI's hosted tools add real surcharges: web search $10 per 1,000 calls, file search $2.50 per 1,000 calls, and Code Interpreter containers $0.03–$1.92 per 20-minute session.
- OpenAI is winding down Agent Builder and Evals after November 30, 2026, pointing developers to the code-first Agents SDK — a sign the SDK is the durable path.
Head to head
| Dimension | Claude Agent SDK | OpenAI Agents SDK |
|---|---|---|
| Pricing | No SDK fee; Haiku 4.5 $1/$5 per 1M tokens; Fable 5.1 $10/$50; Max/Team plans include $100–$500 monthly API credits | No SDK fee; GPT-6 Luna $0.10/$0.50 per 1M tokens; GPT-6 Astra $10/$50; Business seats $20–$100/user/month 🏆 |
| Ease of use | Link a Console org to claim credits automatically; no payment method needed on Claude Platform | Single Responses API primitive with SDK helpers like response.output_text and unified streaming events |
| Features | Shares billing with Claude API, Managed Agents, and playground; prompt caching; per-workspace spend limits | Built-in web search, file search, computer use, hosted containers, tracing/observability, multi-agent handoffs and guardrails 🏆 |
| Support | Support channel for credit/eligibility issues; Enterprise adds audit logs and custom data retention | Centralized billing and administration on Business plans; usage analytics and spend controls |
| Integrations | Claude for Microsoft 365 and Outlook; Slack and Google Workspace on consumer plans; AWS Bedrock and Google Cloud not covered by credits | Google Workspace, Slack, GitHub, Microsoft 365 on Business plans; CI-friendly API-key access 🏆 |
| Setup | Requires an eligible plan and linking a Console organization to claim credits; new subscribers wait 7 days | API key is enough; works in shared environments like CI with no cloud features required 🏆 |
| Cost controls | Monthly spend caps reset on the 1st; per-workspace spend limits; prompt caching; credits expire monthly with no rollover | Cached input at 1/10th rate; return_token_budget caps search tokens; Business spend controls and usage analytics |
The contenders
The OpenAI Agents SDK is the open-source orchestration layer OpenAI launched in March 2025 alongside the Responses API, handling the agent loop, handoffs, and guardrails inside your own application. It sits on top of the Responses API — a superset of Chat Completions that combines tool-use capabilities with a unified item-based design, intuitive streaming events, and SDK helpers like response.output_text. Built-in hosted tools include web search, file search, and computer use, plus hosted containers for shell and code execution, and integrated observability tools to trace and inspect agent workflow execution. In October 2025 OpenAI added AgentKit (Agent Builder, Connector Registry, ChatKit, expanded Evals) and later a managed Agents API runtime, though Agent Builder and Evals are being retired after November 30, 2026 in favor of the code-first SDK. There is no separate SDK fee: tokens and tools are billed at standard API rates. For small businesses, the practical cost driver is model choice — GPT-6 Luna at $0.10/$0.50 per 1M tokens makes lightweight agents extremely cheap, while GPT-6 Astra at $10/$50 serves demanding workloads. Prompt caching at one-tenth the fresh input rate materially reduces costs for multi-turn agents that re-send growing context.
pricing 20/month
- + No SDK license fee — tokens and tools billed at standard API rates
- + GPT-6 Luna at $0.10/$0.50 per 1M tokens is by far the cheapest agent-capable model of the two platforms
- + Built-in hosted tools (web search, file search, containers) remove the need to integrate external vendors
- + Cost controls for multi-turn agents: cached input at one-tenth fresh rates, plus return_token_budget to cap search-result tokens
- + Business plans include no training on business data by default, SAML SSO, MFA, and centralized billing for teams of 2–200
- − Long-context pricing kicks in above 272,000 input tokens at roughly double rates — Anthropic charges no long-context tier
- − Hosted tool surcharges stack: a web-search-heavy agent pays $10 per 1,000 searches plus the model tokens those results consume
- − Agent Builder and Evals are being retired after November 30, 2026, forcing migration to the code-first SDK
- − Flagship GPT-6 Astra output tokens at $50/1M can escalate quickly in agent loops where every turn is a model call
The Claude Agent SDK is Anthropic's developer toolkit for building and running agents programmatically, covered under the Claude Platform (Claude Console) billing surface. It shares billing with the Claude API, Claude Managed Agents, and the playground, and — importantly for small teams — is included in the monthly API credits that come with Claude Max 5x ($100/month in credits), Max 20x ($200/month), and Team plans (up to $500/month pooled across seats). Credits arrive each billing cycle in a linked Claude Console organization, require no payment method on the platform, and expire at the end of each cycle with no rollover. API token rates per 1M tokens run $1/$5 for Haiku 4.5, $2/$10 for Sonnet 5, $4/$20 for Opus 5.5, and $10/$50 for Fable 5.1, with prompt caching available to reduce repeated-input costs in multi-turn agents. Anthropic does not charge a separate long-context tier, which matters for agents holding large histories. One operational gotcha: if ANTHROPIC_API_KEY is set in your shell, Claude Code bills at API rates and ignores your subscription entirely. The SDK suits teams already inside the Claude ecosystem — Pro, Max, Team, and Enterprise subscribers get bundled access, and Enterprise adds SSO, audit logs, and custom data retention.
pricing 20/month
- + Monthly API credits ($100–$500 depending on plan) effectively subsidize agent development for existing Claude subscribers
- + No long-context pricing tier, unlike OpenAI's ~2x surcharge above 272K input tokens
- + Per-workspace spend limits give granular budget control over individual agent projects
- + Credits need no payment method on Claude Platform, lowering the barrier for teams on eligible plans
- + Enterprise-grade options: SSO, audit logs, custom data retention for larger deployments
- − Cheapest API model (Haiku 4.5 at $1/$5 per 1M tokens) costs about 10x OpenAI's GPT-6 Luna at the entry tier
- − Credits expire at the end of each billing cycle with no rollover — unused budget is lost
- − Free and Pro plans are not eligible for API credits; you need Max or Team to get them
- − An ANTHROPIC_API_KEY set in your shell causes billing at API rates, silently bypassing your subscription
- − Weekly usage limits on subscription plans can automatically switch to pay-per-token mode without warning
Verdict
Winner: OpenAI Agents SDK
Both SDKs carry no license fee, so the decision comes down to model token costs and ecosystem fit — and OpenAI's GPT-6 Luna at $0.10/$0.50 per 1M tokens undercuts Anthropic's cheapest API model (Haiku 4.5 at $1/$5) by roughly 10x at the entry tier. Claude wins on subscription-bundled API credits for teams already paying for Max or Team plans, but on raw build cost OpenAI is cheaper for most small-business agent projects.
| Option | Overall | Breakdown |
|---|---|---|
| OpenAI Agents SDK | 8.2 | : 9: 8: 9: 7: 8: 8 |
| Claude Agent SDK | 7.6 | : 7: 8: 8: 7: 8: 7 |
Pricing compared: no SDK fees, but very different token bills
Features and developer experience
Which fits a small business in 2026?
Which should you pick?
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FAQ
Do the OpenAI Agents SDK or Claude Agent SDK cost anything themselves?
No. OpenAI states the Responses API and Agents SDK are 'not charged separately' — you pay standard API rates for the model tokens and hosted tools your agents use. Anthropic likewise covers the Claude Agent SDK under normal Claude Platform billing, and on Max 5x, Max 20x, and Team plans it's covered by included monthly API credits ($100, $200, and up to $500 pooled respectively). In both cases the SDK is free; your bill comes from tokens and tool calls.
Which SDK is cheaper for a small business building its first agent?
At the entry tier, OpenAI. GPT-6 Luna costs $0.10 input / $0.50 output per 1M tokens, while Anthropic's cheapest agent-capable API model, Haiku 4.5, runs $1/$5 — about 10x more. Mid-tier pricing is identical (GPT-6.1 Sol and Sonnet 5 both $2/$10), and flagships match too (GPT-6 Astra and Fable 5.1 both $10/$50). However, if your business already pays for Claude Max or Team plans, the included monthly API credits can make Claude agent building effectively free within your existing subscription.
How do Claude's API credits work for the Agent SDK?
Max 5x plans include $100/month, Max 20x $200/month, and Team plans pool credits across seats up to $500/month. You link a Claude Console organization to your eligible plan, and credits arrive each billing cycle — no payment method required on Claude Platform. Credits cover the Claude API, Claude Managed Agents, the Claude Agent SDK, and the playground, but not Claude Code or Claude Platform on AWS, Bedrock, Google Cloud, or Microsoft Foundry. Unused credits expire at the end of each billing cycle with no rollover, and Free, Pro, and Enterprise plans are not eligible.