Memory Step

MemoryStepDescription performs an operation on the context’s namespaced memory store — useful for stashing intermediate results that later steps read back.

MemoryStepConfig

Field	Type	Default	Purpose
operation	MemoryOperation	— (required)	read / write / append / delete / list.
memory_key	str	— (required)	Key in the memory store.
value_source	str | None	None	Where the value comes from on write/append (e.g. "$history[-1]").
default_value	Any	None	Returned on read when the key is missing.
namespace	str	"default"	Namespace for isolation.

Memory is organised by namespace → key. Read it back elsewhere with the $memory.namespace.key reference.

Example: write then read

from mmar_carl import MemoryStepDescription, MemoryStepConfig, MemoryOperation

# Step 3 stores step 2's output under results/analysis
MemoryStepDescription(
    number=3,
    title="Store result",
    dependencies=[2],
    config=MemoryStepConfig(
        operation=MemoryOperation.WRITE,
        memory_key="analysis",
        value_source="$history[-1]",
        namespace="results",
    ),
)

# A later step reads it back
MemoryStepDescription(
    number=5,
    title="Retrieve result",
    config=MemoryStepConfig(
        operation=MemoryOperation.READ,
        memory_key="analysis",
        namespace="results",
        default_value="(missing)",
    ),
)

Note

During parallel execution each step gets a copy-on-write view of memory. Writes from parallel siblings are not visible to each other — only to subsequent batches.

See also

• Dynamic references — reading memory with $memory.*.
• Building chains — the add_memory_step() shortcut.