Working Memory
The information currently available to an AI inside its active context window — what it can 'see' and work with right now. Like human short-term memory: once something falls outside the context window, the AI can no longer access it. Managing working memory well — deciding what to keep in context and what to retrieve from external storage — is a key challenge in building agents that work reliably on long tasks.
In practice
You're in the middle of a long conversation with Claude where you've shared a lot of context — your goals, constraints, previous decisions. Working memory is what Claude holds in mind right now, within this active session. Unlike long-term memory, it doesn't persist after the conversation ends. The context window is the boundary of Claude's working memory.
Related concepts