Microsoft says new features in its Foundry Agent Service platform have cut AI agent operating costs by up to 97% in internal testing, as part of a broader push to reduce what it calls the "context engineering" overhead of enterprise AI agents.
In a blog post published 2 September by Jeff Hollan, vice president of product management for Foundry Agent Service, Microsoft said internal benchmarking against a public open-source tool-retrieval dataset showed a new feature called Toolboxes cut average input-token consumption by around 97% for agents with large tool libraries. Toolboxes give an agent a single managed endpoint for its tools, rather than sending a full tool-description list to the model on every turn.
The company also detailed Foundry IQ, a managed knowledge layer that narrows what enters an agent's context window by decomposing queries, searching connected sources such as SharePoint, OneLake and Azure SQL in parallel, and returning only the most relevant passages with citations. At query time, Microsoft said Foundry IQ can run under a caller's Microsoft Entra identity, synchronise access-control lists, and honour Microsoft Purview sensitivity labels, so an agent retrieves only content the caller is authorised to access. Microsoft said internal evaluations showed Foundry IQ improved evidence recall by up to 54% on the BrowseComp-Plus benchmark while cutting retrieval token costs by 34%.
The post also described reusable "skills" for encoding company procedures centrally rather than duplicating them across agents, and three types of memory, covering the current session, persistent user preferences, and learned task-execution patterns. Microsoft said enabling procedural memory produced roughly a 5% improvement on the STATE-Bench and Tau-Bench evaluation benchmarks.
The post forms the third instalment in Microsoft's four-part "Economics of Agent Optimization" series on Foundry, following earlier posts on cost decisions and runtime request handling.
