cache_set

Store a string value under a key in the cache. Values expire automatically after 1 hour.

Parameters

Parameter	Type	Required	Description
key	string	Yes	The cache key under which the value is stored.
value	string	Yes	The string value to store. Serialize complex values (e.g. to JSON) before calling this tool.

Response

Field	Type	Description
success	boolean	Always true on success — confirms the write completed without error.

Example

{
	"key": "my-session-data",
	"value": "{\"step\":3,\"items\":[\"a\",\"b\"]}"
}

Result:

{
	"success": true
}

Errors

Each failure carries a precise code in the response. Argument-schema and server errors are JSON-RPC protocol errors; a rejected value is returned as a tool result with isError: true (so the agent can read the code and self-correct).

Code	When	Delivered as
invalid_arguments	The key or value argument is missing or the wrong type.	protocol error (invalid_params)
invalid_cache_key	The key is empty or contains a disallowed character such as :.	tool error (isError)
value_too_large	The value exceeds the maximum size of 256 KB.	tool error (isError)
tool_not_configured	The cache backend is not available on this server.	tool error (isError)
internal_error	An unexpected error occurred while accessing the cache.	protocol error (internal_error)
method_not_found	The tool isn't available to your credential.	protocol error (method_not_found)

Notes

• Cache entries are scoped to your credential: a personal credential's entries are private to you, while an organization credential shares one cache across the organization. Keys never cross that boundary.
• Keys must not contain :.
• Only string values are accepted. Serialize objects or arrays to JSON before storing them.
• Writing to an existing key overwrites the previous value and resets the expiry to 1 hour.
• Values are limited to 256 KB. Larger values must be split across multiple keys.