Struct FanOut 

pub struct FanOut {
    pub outcomes: Vec<ProviderOutcome>,
}

The result of fanning one query out across all capability-matching providers.

Fields

outcomes: Vec<ProviderOutcome>

One entry per provider that matched the query’s frame kinds, in registration order.

Implementations

impl FanOut

pub fn accepted_frames(&self) -> impl Iterator<Item = &ContextFrame>

Every frame from providers that passed the consent gate, the timeout, and the budget-honesty audit — the frames a host may honestly compose into a prompt.

pub fn total_accepted_tokens(&self) -> u64

The summed honest token cost of every accepted frame.

pub fn accepted_with_provider( &self, ) -> impl Iterator<Item = (&str, &ContextFrame)>

Every accepted frame paired with the id of the provider that served it — the input to deterministic composition (docs/context-reuse.md §1).

pub fn compose(&self) -> String

Compose every accepted frame into a byte-stable context block via the deterministic composition contract — canonical order, relevance-free rendering (docs/context-reuse.md §1). Two fan-outs over the same frame set compose to identical bytes, so an unchanged turn extends the provider’s prompt cache instead of busting it.

pub fn attestation_ledger(&self) -> AttestationLedger

Every accepted frame’s attestation state, keyed by identity (SPEC.md §6.5, ADR 0016).

A total account of the accepted frames: a frame the provider signed nothing for is Unattested, so a missing entry never has to be guessed at. Frames from a leg that served none — failed, timed out, consent-gated, budget-dropped — are absent because there is nothing to say about frames the host does not hold.

pub fn any_attested(&self) -> bool

Whether any accepted frame is attested by a key this host trusts. A host rendering a “this evidence is signed” affordance asks this before drawing the chrome.

pub fn compose_for_prompt(&self, global_budget: u32) -> ComposedPrompt

Compose every accepted frame into a prompt-ready block via the reference composer (issue #15): the R3 evidence preamble, cross-provider-deduped and value-ordered fenced frames packed under global_budget, a citation map, and a CompositionAudit explaining every included and excluded frame. Pair with Host::query_all_budgeted: the fan-out splits the budget across providers, and this packs the survivors under the same whole so audit.tokens_used <= global_budget.

Each audit entry also carries this fan-out’s attestation_ledger state, so a reader can tell attested evidence from unattested. It changes nothing about which frames are chosen or where they land: acting on the state is a host’s policy decision, and F9 forbids the composer from making it.

Ranks by raw score (ScoreDescending); a host with its own cross-provider policy calls compose_for_prompt_with.

pub fn compose_for_prompt_with<S>( &self, global_budget: u32, strategy: &S, ) -> ComposedPrompt

where S: RankingStrategy + ?Sized,

compose_for_prompt under an explicit cross-provider ranking policy (SPEC.md §6.6, F10), still carrying this fan-out’s attestation ledger into the audit.

The two are orthogonal by construction: the strategy decides which frames are packed and in what order, and the ledger only describes what was found about each one. Nothing here lets an attestation state move a frame, which is what keeps F9 true no matter which policy a host picks.

pub fn usage_report( &self, query: &ContextQuery, as_of: impl Into<String>, ) -> UsageReport

Roll this fan-out up into a per-request UsageReport for metering (docs/context-reuse.md §2). One ProviderUsage per provider the query reached: accepted frames are itemized by stable identity and declared cost, a budget-lying provider’s dropped frames count as rejected, and a failed or consent-gated provider served nothing.

The report is a pure function of this fan-out plus the two host-supplied scalars: budget_requested is the query’s max_tokens, and as_of is the accounting snapshot time (an RFC 3339 string the host stamps — the report’s own as-of, not the query’s bi-temporal as_of pin). The result always satisfies UsageReport::is_consistent: its totals are summed from the same served frames it itemizes.

pub fn failures(&self) -> impl Iterator<Item = (&str, &HostError)>

Providers that failed (error, timeout, or crash), with their errors.

pub fn budget_liars(&self) -> impl Iterator<Item = &ProviderOutcome>

Providers whose frames were dropped for exceeding the query budget — the loud report the host must surface, never swallow (SPEC.md §7, B2).

pub fn frame_floods(&self) -> impl Iterator<Item = &ProviderOutcome>

Providers whose frames were dropped for exceeding max_frames — the frame-count twin of budget_liars, surfaced loudly rather than silently truncated (SPEC.md §7, B4).

Trait Implementations

impl Debug for FanOut

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

Formats the value using the given formatter.