Memory tool

The memory tool lets Claude store and retrieve information across conversations in a directory of memory files. Claude can create, read, update, and delete files that persist between sessions, building up knowledge over time without keeping everything in the context window.

Memory supports just-in-time context retrieval. Rather than loading all relevant information up front, an agent records what it learns in memory files and reads them back on demand. This keeps the active context focused on the current task, which matters for long-running sessions that would otherwise overwhelm the context window. See Effective context engineering for the broader pattern.

The memory tool operates client-side: Claude requests file operations, and your application executes them. You control where and how the data is stored through your own infrastructure.

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Use cases

• Maintain project context across multiple agent sessions
• Apply lessons from past interactions, decisions, and feedback to new tasks
• Build up a knowledge base over time

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How it works

When the memory tool is enabled, Claude automatically checks its memory directory before starting a task. As it works, Claude stores what it learns in files under /memories and reads them back in later conversations to continue earlier work.

Because the memory tool is client-side, Claude only requests memory operations. Your application executes each request against storage you control and returns the result in a tool_result block (see Handle tool calls). The /memories path is a prefix that your handler maps onto real storage, such as a per-user directory or keys in a database. Memory lives entirely in your application. A later conversation continues from the same memory when it sends the same tools entry and your handler serves the same store. For security, restrict all memory operations to the /memories directory (see Path traversal protection).