Struct SystemBlock 

pub struct SystemBlock {
    pub block_type: String,
    pub text: String,
    pub cache_control: Option<CacheControl>,
}

A block in a structured system prompt.

Fields

block_type: String

Type of the block (always “text” for now).

text: String

Text content.

cache_control: Option<CacheControl>

Optional cache control.

Implementations

impl SystemBlock

pub fn cached(text: impl Into<String>) -> Self

Create a new system block with caching enabled (default TTL).

pub fn cached_with_ttl(text: impl Into<String>, ttl: CacheTtl) -> Self

Create a new system block with caching and specific TTL.

Per Anthropic best practices:

• Use OneHour for static content (system prompts, tools)
• Use FiveMinutes for dynamic content (messages)

pub fn uncached(text: impl Into<String>) -> Self

Create a new system block without caching.

Trait Implementations

impl Clone for SystemBlock

fn clone(&self) -> SystemBlock

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for SystemBlock

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for SystemBlock

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for SystemBlock

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.