Side-by-side
| Axis | Claude (Anthropic) | GPT (OpenAI) |
|---|---|---|
| Setup time | Anthropic API key, base URL https://api.anthropic.com. Native tool-use protocol. | OpenAI API key, base URL https://api.openai.com. Function-calling ABI. |
| Security model | SOC 2, EU residency available, no training on API data. | SOC 2, EU residency available, no training on API data (since March 2024). |
| Model support | Claude 4.5 Sonnet (default), Claude 4.7 Opus (premium reasoning), Haiku (fast/cheap). | gpt-4o, gpt-4o-mini, gpt-4 (legacy), o1 (reasoning). |
| Cost | Sonnet $3/M in $15/M out. Haiku $0.80/M in $4/M out. Prompt caching: 50-90% reduction on stable system prompts. | gpt-4o $2.50/M in $10/M out. gpt-4o-mini $0.15/M in $0.60/M out. Cheap mini tier is a real advantage. |
| Ecosystem | Native tool-use feels best in agent code. Vision support is excellent. | Function calling is everywhere; embeddings ecosystem is mature. |
| Best for | Agents where tool-use protocol quality matters most — code review, document Q&A, complex orchestration. | High-volume classification, dense low-latency calls (gpt-4o-mini), embeddings work. |
Verdict
Use both. Claude Haiku for cheap classification when latency permits, Claude Sonnet 4.5 for quality reasoning, gpt-4o-mini for cents-per-million volume work, gpt-4o for parity sanity-check on important threads. OpenRouter makes the switch trivial.
Notes
- Anthropic prompt caching is the single biggest cost win for long, stable system prompts. Set it up.
- OpenAI's structured output (JSON mode + schema enforcement) is more polished than Anthropic's equivalent.
- Both vendors are improving monthly; figures here are accurate to April 2026.
Going deeper
For the full landscape report including hosting economics, security posture and regulatory context, see the 2026 landscape report. For the OpenClaw-specific history, see the complete OpenClaw timeline.
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