Files
Termind/TFMTests/AgentTokenUsageTests.swift
T

377 lines
14 KiB
Swift

import AgentKit
import Foundation
import TermindApplication
import TermindDomain
import TermindInfrastructure
import TermindPersistence
import TermindPresentation
import TermindRemoteInfrastructure
import Testing
@testable import Termind
extension [AgentModelStreamEvent] {
fileprivate var firstUsage: AgentTokenUsage? {
for case .usage(let usage) in self { return usage }
return nil
}
}
/// Token accounting, from four vendors' spellings through to the split the
/// context gauge shows.
@Suite
struct AgentTokenUsageTests {
// MARK: - Provider parsing
@Test
func responsesReportsUsageWithCachedShare() {
let events = AgentProviderClient.parseCompletedResponses([
"object": "response", "status": "completed", "output": [],
"usage": [
"input_tokens": 12_000, "output_tokens": 340,
"input_tokens_details": ["cached_tokens": 9_500],
],
])
#expect(events.firstUsage?.inputTokens == 12_000)
#expect(events.firstUsage?.outputTokens == 340)
#expect(events.firstUsage?.cachedInputTokens == 9_500)
// The cached figure is a subset of the prompt total for this vendor, so
// it must not have been added on top of it.
#expect(events.firstUsage?.contextTokens == 12_340)
}
/// OpenAI sends usage on a final chunk with an empty `choices` array. The
/// parser used to return early on exactly that shape.
@Test
func chatCompletionsReadsUsageFromTheChunkWithNoChoices() {
let events = AgentProviderClient.parseChat([
"choices": [[String: Any]](),
"usage": [
"prompt_tokens": 8_192, "completion_tokens": 128,
"prompt_tokens_details": ["cached_tokens": 4_096],
],
])
#expect(events.firstUsage?.inputTokens == 8_192)
#expect(events.firstUsage?.outputTokens == 128)
#expect(events.firstUsage?.cachedInputTokens == 4_096)
}
@Test
func chatCompletionsStreamingBodyAsksForUsage() throws {
let client = AgentProviderClient(
provider: ModelProvider(name: "Compatible", apiFormat: .chatCompletions),
model: AIModel(id: "gpt-5"),
secret: "key"
)
let request = AgentModelRequest(
systemPrompt: "system", messages: [], tools: []
)
let streaming = client.body(request, streaming: true)
let options = try #require(streaming["stream_options"] as? [String: Any])
#expect(options["include_usage"] as? Bool == true)
// Not on the buffered path: several OpenAI-compatible gateways reject
// the key outright when `stream` is false.
#expect(client.body(request, streaming: false)["stream_options"] == nil)
}
/// The one vendor whose `input_tokens` is not the prompt total. With prompt
/// caching working, taking it at face value reads near-empty on a context
/// that is nearly full.
@Test
func anthropicAddsCacheTokensIntoTheInputTotal() {
let events = AgentProviderClient.parseAnthropic(
"message_start",
[
"message": [
"usage": [
"input_tokens": 220,
"cache_read_input_tokens": 96_000,
"cache_creation_input_tokens": 1_800,
]
]
])
#expect(events.firstUsage?.inputTokens == 98_020)
#expect(events.firstUsage?.cachedInputTokens == 96_000)
}
@Test
func anthropicReportsOutputOnMessageDelta() {
let events = AgentProviderClient.parseAnthropic(
"message_delta", ["usage": ["output_tokens": 512]]
)
#expect(events.firstUsage?.outputTokens == 512)
}
@Test
func googleReadsUsageFromAChunkWithNoCandidates() {
let events = AgentProviderClient.parseGoogle([
"usageMetadata": [
"promptTokenCount": 4_400, "candidatesTokenCount": 210,
"cachedContentTokenCount": 2_048,
]
])
#expect(events.firstUsage?.inputTokens == 4_400)
#expect(events.firstUsage?.outputTokens == 210)
#expect(events.firstUsage?.cachedInputTokens == 2_048)
}
/// A gateway is free to send `1024.0`, and reading these as `Int` directly
/// returns nil for that.
@Test
func usageSurvivesFloatingPointCounts() {
let events = AgentProviderClient.parseChat([
"choices": [[String: Any]](),
"usage": ["prompt_tokens": 1024.0, "completion_tokens": 16.0],
])
#expect(events.firstUsage?.inputTokens == 1_024)
#expect(events.firstUsage?.outputTokens == 16)
}
// MARK: - Merging
/// Anthropic and Gemini both report cumulatively across several events of
/// one turn. Summing would multiply the count by the number of chunks.
@Test
func mergingTakesTheHighestOfEachFieldRatherThanSumming() {
let start = AgentTokenUsage(inputTokens: 98_020, cachedInputTokens: 96_000)
let firstDelta = start.merging(AgentTokenUsage(outputTokens: 120))
let secondDelta = firstDelta.merging(AgentTokenUsage(outputTokens: 512))
#expect(secondDelta.inputTokens == 98_020)
#expect(secondDelta.cachedInputTokens == 96_000)
#expect(secondDelta.outputTokens == 512)
}
@Test
func emptyUsageIsDistinguishableFromAZeroCostTurn() {
#expect(AgentTokenUsage().isEmpty)
#expect(!AgentTokenUsage(inputTokens: 1).isEmpty)
}
// MARK: - Estimate
@Test
func estimateSeparatesToolResultsFromTheConversation() {
let estimate = AgentContextEstimator.estimate(
systemPrompt: String(repeating: "s", count: 400),
toolSchemaCharacters: 800,
transcript: [
AgentTranscriptMessage(role: .user, text: String(repeating: "u", count: 400)),
AgentTranscriptMessage(
role: .tool, text: String(repeating: "t", count: 4_000),
toolCallID: "call-1", toolName: "ssh_exec"
),
],
attachedCharacters: 200,
measured: nil
)
#expect(estimate.tokens(.systemPrompt) == 100)
#expect(estimate.tokens(.tools) == 200)
#expect(estimate.tokens(.conversation) == 100)
#expect(estimate.tokens(.toolResults) == 1_000)
#expect(estimate.tokens(.attachments) == 50)
#expect(estimate.total == 1_450)
#expect(!estimate.isMeasured)
}
/// The breakdown sits directly under the total it belongs to. Two numbers on
/// one screen that disagree leave the reader no way to tell which is wrong.
@Test
func measuredTotalRescalesThePartsToSumExactly() {
let estimate = AgentContextEstimator.estimate(
systemPrompt: String(repeating: "s", count: 400),
toolSchemaCharacters: 800,
transcript: [
AgentTranscriptMessage(role: .user, text: String(repeating: "u", count: 4_000))
],
attachedCharacters: 0,
measured: AgentTokenUsage(inputTokens: 3_000, outputTokens: 500)
)
#expect(estimate.isMeasured)
#expect(estimate.total == 3_500)
#expect(estimate.parts.values.reduce(0, +) == 3_500)
// Proportions survive: the conversation was ~77% of the estimate.
#expect(estimate.tokens(.conversation) > estimate.tokens(.tools))
}
@Test
func shareIsNilWithoutAKnownContextWindow() {
let estimate = AgentContextEstimator.estimate(
systemPrompt: "s", toolSchemaCharacters: 0, transcript: [],
attachedCharacters: 0, measured: nil
)
#expect(estimate.share(of: nil) == nil)
#expect(estimate.share(of: 0) == nil)
}
@Test
func shareIsClampedSoAnOverfullContextCannotDrawPastTheRing() {
let estimate = AgentContextEstimator.estimate(
systemPrompt: "", toolSchemaCharacters: 0, transcript: [],
attachedCharacters: 0,
measured: AgentTokenUsage(inputTokens: 300_000)
)
#expect(estimate.share(of: 200_000) == 1)
}
@Test
func aChipAndTheGaugeAgreeOnWhatAnAttachmentCosts() {
let content = String(repeating: "x", count: 4_000)
let chip = ContextChip(kind: .output, label: "Last 200 lines", content: content)
#expect(chip.approximateTokens == AgentContextEstimator.tokens(inCharacters: 4_000))
}
@Test
func incrementalTrackerMatchesTheReferenceEstimator() {
let user = AgentTranscriptMessage(
role: .user, text: String(repeating: "u", count: 400)
)
let tool = AgentTranscriptMessage(
role: .tool, text: String(repeating: "t", count: 4_000),
toolCallID: "call", toolName: "lookup"
)
let tracker = AgentContextEstimateTracker(
systemPrompt: AgentSystemPrompt.default,
toolSchemaCharacters: 800,
transcript: [user],
attachedCharacters: 200,
measured: nil
)
tracker.appendStreamingText(String(repeating: "a", count: 120), to: tool.id)
#expect(tracker.snapshot().tokens(.conversation) > 0)
tracker.upsert(tool)
let reference = AgentContextEstimator.estimate(
systemPrompt: AgentSystemPrompt.default,
toolSchemaCharacters: 800,
transcript: [user, tool],
attachedCharacters: 200,
measured: nil
)
#expect(tracker.snapshot() == reference)
let measured = AgentTokenUsage(inputTokens: 3_000, outputTokens: 500)
tracker.setMeasured(measured)
let measuredReference = AgentContextEstimator.estimate(
systemPrompt: AgentSystemPrompt.default,
toolSchemaCharacters: 800,
transcript: [user, tool],
attachedCharacters: 200,
measured: measured
)
#expect(tracker.snapshot() == measuredReference)
tracker.remove([tool.id])
tracker.setMeasured(nil)
#expect(
tracker.snapshot()
== AgentContextEstimator.estimate(
systemPrompt: AgentSystemPrompt.default,
toolSchemaCharacters: 800,
transcript: [user],
attachedCharacters: 200,
measured: nil
)
)
}
@Test
func composerDraftEditsNeverRebuildTheContextEstimate() {
let transcript = (0..<300).map { index in
AgentTranscriptMessage(
role: index.isMultiple(of: 2) ? .user : .assistant,
text: String(repeating: "message \(index) ", count: 80)
)
}
let conversation = ConversationModel(transcript: transcript)
let rebuilds = conversation.contextEstimateFullRebuildCount
let estimate = conversation.contextEstimate
for revision in 0..<100 {
conversation.composer.draft = "draft \(revision)"
_ = conversation.contextEstimate
}
#expect(conversation.contextEstimateFullRebuildCount == rebuilds)
#expect(conversation.contextEstimate == estimate)
}
@Test
func conversationSnapshotTracksAttachmentsHistoryEditsAndUsage() throws {
let conversation = ConversationModel()
conversation.attach(
ContextChip(
kind: .output, label: "diagnostic",
content: String(repeating: "a", count: 400)
)
)
expectSnapshotMatchesReference(conversation)
let opening = conversation.appendUserTurnContent("inspect")
let assistant = AgentTranscriptMessage(role: .assistant, text: "answer")
conversation.handle(.messageFinished(assistant))
expectSnapshotMatchesReference(conversation)
let invocation = AgentToolInvocation(
runID: UUID(),
call: AgentToolCall(id: "call", name: "lookup", arguments: .object([:]))
)
conversation.handle(
.toolFinished(
invocation,
AgentToolResult(callID: "call", content: String(repeating: "r", count: 800))
))
expectSnapshotMatchesReference(conversation)
_ = try #require(conversation.editUserMessage(opening.id, authoredText: "edited"))
expectSnapshotMatchesReference(conversation)
conversation.applyCompaction(summary: "summary", cut: 1)
expectSnapshotMatchesReference(conversation)
conversation.handle(.usageUpdated(AgentTokenUsage(inputTokens: 2_000, outputTokens: 80)))
expectSnapshotMatchesReference(conversation)
let forkSource = ConversationModel()
forkSource.appendUserTurn("question")
let forkAnswer = AgentTranscriptMessage(role: .assistant, text: "answer")
forkSource.handle(.messageFinished(forkAnswer))
let fork = try #require(forkSource.forked(throughAssistantMessage: forkAnswer.id))
expectSnapshotMatchesReference(fork)
}
private func expectSnapshotMatchesReference(_ conversation: ConversationModel) {
let attachedCharacters = conversation.composer.attachments.reduce(0) {
$0
+ ($1.image == nil
? AgentContextEstimator.characterUnits(in: $1.content)
: $1.approximateTokens * AgentContextEstimator.charactersPerToken)
}
#expect(
conversation.contextEstimate
== AgentContextEstimator.estimate(
systemPrompt: TermindAgentPolicy.systemPrompt,
toolSchemaCharacters: conversation.toolSchemaCharacters,
transcript: conversation.transcript,
attachedCharacters: attachedCharacters,
measured: conversation.usage
)
)
}
}