Constrain a session or a single run:

use Clutch\Laravel\ValueObjects\RunBudget;

$session = Clutch::agent(ResearchAgent::class)
    ->for($user)
    ->budget(new RunBudget(
        maxSteps: 40,
        maxToolCalls: 100,
        maxTokens: 250_000,
        maxCostUsd: 8.00,
        maxDurationSeconds: 900,
    ))
    ->create();

Budgets layer: configuration defaults first, then the session, then the run. At each level the more restrictive limit wins, so a session can tighten a ceiling but never raise it.

A run that hits a hard limit moves to budget_exceeded, emits a terminal event naming the limit that ran out, and keeps its last safe checkpoint.

Usage carries across attempts, so a retry loop cannot spend the same budget three times. Reset it when you actually mean to:

$run->retry(resetBudget: true);

maxCostUsd needs prices to work against:

// config/clutch.php
'pricing' => [
    'anthropic:claude-sonnet-4-5' => ['input' => 3.00, 'output' => 15.00],
    'openai:gpt-5' => ['input' => 1.25, 'output' => 10.00],
],

An unpriced model contributes 0.00 rather than a guess. That shows up in the usage record, which beats a plausible number that happens to be wrong.