Macro completion_parent_span 

macro_rules! completion_parent_span {
    (
        target: $target:literal,
        parent: $parent:expr,
        name: $name:literal,
        operation: $operation:expr,
        system_instructions: $system:expr
        $(, $($extra:tt)*)?
    ) => { ... };
    (
        target: $target:literal,
        name: $name:literal,
        operation: $operation:expr,
        system_instructions: $system:expr
        $(, $($extra:tt)*)?
    ) => { ... };
}

Declare a completion-parent span conforming to the adoption contract.

This macro is the single declarative source of the contract: it declares COMPLETION_PARENT_MARKER_FIELD and every field in COMPLETION_PARENT_REQUIRED_FIELDS, so a span it builds is always adoptable by CompletionSpanBuilder::build and can absorb every field recorded over the completion’s lifetime. Runtimes should declare their completion-parent spans through it rather than hand-writing the marker and field list — tracing::Span::record silently no-ops on undeclared fields, so a hand-written span that omits one field loses that telemetry with no error (and a span that omits enough to fail the adoption gate is not adopted at all). A span declared through this macro tracks the contract automatically; a hand-written one has to be maintained by hand.

By default the span is explicitly parented on tracing::Span::current(); pass parent: <expr> between target and name to override it with any parent expression tracing::info_span! accepts (including None). operation and system_instructions are declared with the given values; the provider records gen_ai.provider.name and gen_ai.request.model at adoption time. Additional runtime-specific fields may be appended after the named arguments. Extra fields must not repeat the marker or a required contract field: a duplicate compiles, but the span then declares two same-named fields and tracing::Span::record targets only the first.

Invoking this macro does not require a direct tracing dependency. To declare a field with no value yet, use Empty (re-exported here for exactly this reason) or Option::<&str>::None; tracing::field::Empty itself is the same type but only nameable by a crate that depends on tracing directly.

Examples

use rig_core::telemetry::completion_parent_span;

let span = completion_parent_span!(
    target: "my_runtime",
    name: "chat",
    operation: "chat",
    system_instructions: Option::<&str>::None,
    gen_ai.agent.name = "assistant",
);