eve
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Filesystem-first framework for durable backend AI agents that run anywhere.
120 lines (119 loc) • 6 kB
TypeScript
/**
* Token-usage accumulator for `$eve.*` observability tags and session limits.
* Lives on `session.state` so the totals survive workflow step boundaries the
* way the rest of the harness state does.
*
* The harness runs each turn as a sequence of `"use step"` invocations
* (one per tool-loop iteration). Each step knows its own
* `result.usage`, but the dashboard cares about totals **per turn**.
* The workflow runtime's attribute store is "last write wins" per key,
* so the simplest cumulative pattern is: read the previous total from
* `session.state`, add the new step's usage, write the running total
* back. The most recent emit then carries the final per-turn total.
*
* `turnId` keys the turn totals so a fresh turn starts at zero without relying
* on a separate "reset" code path. Session totals stay in the same state record
* and keep accumulating until the durable session ends.
*
* `TokenUsageTotals` carries `sawCost` alongside the shared token and token-cost
* fields so observability can distinguish an unreported cost from a reported
* zero. {@link toUsage} drops that internal marker when a total crosses into
* the shared {@link TokenUsage} contract.
*/
import type { HarnessSession, SessionStateMap } from "#harness/types.js";
import { type SessionRuntimeUsageLimits, type SessionUsageLimitViolation } from "#harness/session-usage-limits.js";
import type { TokenUsage } from "#shared/token-usage.js";
export type { SessionRuntimeUsageLimits, SessionUsageLimitViolation };
export interface TokenUsageTotals {
readonly cacheReadTokens: number;
readonly cacheWriteTokens: number;
readonly costUsd: number;
readonly inputTokens: number;
readonly outputTokens: number;
readonly sawCost: boolean;
}
export type TokenUsageDelta = Partial<TokenUsageTotals>;
/**
* Rolling token usage for the durable session and the in-flight turn.
*
* `turnId` is the in-flight turn's stable id; when the harness step
* runs in a different turn, the flat turn totals reset. The nested
* `session` totals do not reset.
*/
export interface TurnUsageState extends TokenUsageTotals {
readonly session: TokenUsageTotals;
readonly turnId: string;
}
/** Reads the stored per-turn token state, or `undefined` when absent. */
export declare function getTurnUsageState(state: SessionStateMap | undefined): TurnUsageState | undefined;
export declare function getSessionTokenUsage(session: Pick<HarnessSession, "state">): TokenUsageTotals;
/** Projects a {@link TokenUsageTotals} down to the cross-cutting {@link TokenUsage} shape. */
export declare function toUsage(totals: TokenUsageTotals): TokenUsage;
/**
* The lifetime-usage ceilings currently in force, per axis. An axis is
* absent when the configured limit leaves it uncapped. Before any granted
* continuation the runtime limit equals the configured limit; each grant
* re-anchors it to `usage + configured limit` via
* {@link bumpSessionRuntimeUsageLimits}.
*/
export declare function getSessionRuntimeUsageLimits(session: Pick<HarnessSession, "limits" | "state">): SessionRuntimeUsageLimits;
/**
* Bumps the runtime usage limits after the user grants a continuation. Each
* capped axis is re-anchored to `current usage + configured limit`, so one
* approval buys one full configured window even after an overshoot. All axes
* bump together to avoid back-to-back prompts. Configured limits never change.
*/
export declare function bumpSessionRuntimeUsageLimits(session: HarnessSession): HarnessSession;
/**
* Remaining lifetime usage quota under the runtime limits, per axis.
* `false` marks an uncapped axis. This is the pool a delegated child's
* budget is granted from.
*/
export declare function getSessionRemainingUsageQuota(session: Pick<HarnessSession, "limits" | "state">): {
costUsd: number | false;
inputTokens: number | false;
outputTokens: number | false;
};
export declare function getSessionUsageLimitViolation(session: Pick<HarnessSession, "limits" | "state">): SessionUsageLimitViolation | null;
/**
* Takes the session-usage delta accumulated since the previous take and
* marks it reported.
*
* Persisted on `session.state` (not in step-local memory) so the entry
* snapshot survives `"use step"` boundaries: the totals at the previous
* settled turn are the totals at this turn's entry, because a parked child
* runs no model calls in between. Blocked parks (authorization, queued
* input) between two settlements never lose usage — the delta always
* measures everything since the last report, so the deltas of a
* multi-turn persistent child sum exactly to its session totals.
*/
export declare function takeSessionUsageDelta(session: HarnessSession): {
readonly delta: TokenUsage;
readonly session: HarnessSession;
};
/** Writes per-turn token state onto a new copy of the session. */
export declare function setTurnUsageState<T extends {
readonly state?: SessionStateMap;
}>(session: T, next: TurnUsageState): T;
/**
* Folds one step's `usage` into the running per-turn totals. When
* `turnId` differs from the stored state (e.g. a new turn just
* started), the previous totals are discarded — fresh turns start at
* zero without an explicit reset path.
*/
export declare function accumulateTurnUsage(input: {
readonly previous: TurnUsageState | undefined;
readonly turnId: string;
readonly usage: TokenUsageDelta | undefined;
}): TurnUsageState;
/**
* Folds a delegated child session's reported totals into the parent's
* session totals without touching the in-flight turn totals. Turn tags
* attribute only the parent's own model calls (child spend is attributed by
* the caller's durable `agent.action` span); session totals feed the session
* token limits and the remaining-quota budget granted to later delegations.
*/
export declare function accumulateSessionUsage(input: {
readonly previous: TurnUsageState | undefined;
readonly usage: TokenUsageDelta;
}): TurnUsageState;