Moonshot AI Kimi K2.5 now available on Workers AI

Workers AI is officially in the big models game. @cf/moonshotai/kimi-k2.5 is the first frontier-scale open-source model on our AI inference platform — a large model with a full 256k context window, multi-turn tool calling, vision inputs, and structured outputs. By bringing a frontier-scale model directly onto the Cloudflare Developer Platform, you can now run the entire agent lifecycle on a single, unified platform.

The model has proven to be a fast, efficient alternative to larger proprietary models without sacrificing quality. As AI adoption increases, the volume of inference is skyrocketing — now you can access frontier intelligence at a fraction of the cost.

Key capabilities

• 256,000 token context window for retaining full conversation history, tool definitions, and entire codebases across long-running agent sessions
• Multi-turn tool calling for building agents that invoke tools across multiple conversation turns
• Vision inputs for processing images alongside text
• Structured outputs with JSON mode and JSON Schema support for reliable downstream parsing
• Function calling for integrating external tools and APIs into agent workflows

Prefix caching and session affinity

When an agent sends a new prompt, it resends all previous prompts, tools, and context from the session. The delta between consecutive requests is usually just a few new lines of input. Prefix caching avoids reprocessing the shared context, saving time and compute from the prefill stage. This means faster Time to First Token (TTFT) and higher Tokens Per Second (TPS) throughput.

Workers AI has done prefix caching, but we are now surfacing cached tokens as a usage metric and offering a discount on cached tokens compared to input tokens (pricing is listed on the model page).

curl -X POST \ "https://api.cloudflare.com/client/v4/accounts/{account_id}/ai/run/@cf/moonshotai/kimi-k2.5" \ -H "Authorization: Bearer {api_token}" \ -H "Content-Type: application/json" \ -H "x-session-affinity: ses_12345678" \ -d '{ "messages": [ { "role": "system", "content": "You are a helpful assistant." }, { "role": "user", "content": "What is prefix caching and why does it matter?" } ], "max_tokens": 2400, "stream": true }'