--- title: Model Routing Is Simple. Until It Isn’t. | daily.dev description: Building model routing into agentic systems is harder than it looks. IBM Research shares three key lessons from real-world experience: (1) actual cost depends... canonical: https://daily.dev/posts/model-routing-is-simple-until-it-isn-t--hk5ukjdm8 twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Model Routing Is Simple. Until It Isn’t. | daily.dev og:description: Building model routing into agentic systems is harder than it looks. IBM Research shares three key lessons from real-world experience: (1) actual cost depends... og:url: https://daily.dev/posts/model-routing-is-simple-until-it-isn-t--hk5ukjdm8 og:image: https://api.daily.dev/og/posts/hk5UkJdm8.png og:image:alt: Model Routing Is Simple. Until It Isn’t. og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Model Routing Is Simple. Until It Isn’t. **[Hugging Face](https://daily.dev/sources/huggingface)** · 5 min read · 0 upvotes · 0 comments ## Summary Building model routing into agentic systems is harder than it looks. IBM Research shares three key lessons from real-world experience: (1) actual cost depends on caching behavior, not just token pricing — Claude Sonnet 4.6 ended up cheaper than GPT-4.1 on the same workload due to cache hit rates; (2) task complexity is invisible at routing time and must be balanced against cost, latency, compliance, and reliability simultaneously; (3) latency is driven by serving infrastructure, not just model size. Their solution reframes routing as a multi-objective optimization problem rather than a classification problem, achieving a 21% cost reduction and 9% latency reduction with only a 4% accuracy drop compared to running a single large model, while keeping the router itself lightweight at ~6ms and 2kB per task. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Multi-Model Routing Is an Infrastructure Decision, Not a Feature: The Tradeoffs Nobody Publishes](https://daily.dev/posts/multi-model-routing-is-an-infrastructure-decision-not-a-feature-the-tradeoffs-nobody-publishes-zbm50wrn5) · DigitalOcean Community · 0 upvotes · 0 comments - [Token Spend Out of Control? The Case for Smarter Routing](https://daily.dev/posts/token-spend-out-of-control-the-case-for-smarter-routing-jxkbskjha) · ByteByteGo · 3 upvotes · 0 comments --- Tags: [#llm](https://daily.dev/tags/llm), [#finops](https://daily.dev/tags/finops) [View this post on daily.dev](https://daily.dev/posts/model-routing-is-simple-until-it-isn-t--hk5ukjdm8) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Model Routing Is Simple. 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