ultracost

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When ultracode is on, the session is pinned to Opus @ xhigh and a single dynamic workflow fans out to dozens of subagents that inherit that session model unless every stage is pinned. ultracost makes per-stage routing explicit, policy-driven, and verifiable — quality-first, so coding and reasoning stay on Opus while pre-planned mechanical work drops to Sonnet. No telemetry. No network on the hot path. MIT.

Built for ultracode (Opus @ xhigh dynamic workflows) — the only place this fan-out happens. ultracost routes by tier (opus/sonnet), not a pinned version, so it tracks whatever Opus your session runs.

Security & trust. ultracost has zero runtime and dev dependencies, so there is no supply chain to compromise — Snyk Open Source and npm audit report 0 vulnerabilities. Releases publish to npm with OIDC Trusted Publishing and signed provenance, every GitHub Action is pinned to a commit SHA, and CodeQL + OpenSSF Scorecard run in CI. The installer touches only its own files and is fully reversible. See SECURITY.md.

Install

Claude Code plugin (recommended):

/plugin marketplace add danielkremen818/ultracost
/plugin install ultracost@ultracost

npm CLI (CI / scripting):

npx ultracost init

Via ClaudePluginHub (one command — adds the marketplace and installs the plugin):

npx claudepluginhub danielkremen818/ultracost --plugin ultracost

First command, in Claude Code: /ultracost:check ./path/to/workflow.js — flag any agent() stage that would silently inherit Opus. Every verb is also a slash command, so plugin users need nothing on PATH.

The problem

When ultracode is on, Claude Code runs the session on Opus @ xhigh (the only model that supports xhigh) and auto-orchestrates dynamic workflows that fan out to dozens — up to 1,000 — subagents. Two defaults compound:

1. Subagents inherit the session model. No per-stage override → every stage runs on the session's Opus.
2. The built-in workflow guidance tells Claude to omit the per-agent model. So inheritance wins.

The documented result: one prompt spawning 46 Opus subagents and ~3M tokens with no warning. A grep sweep and a per-file verifier do not need Opus. (Why ultracode makes this worse →)

The evidence: nobody pins a stage

This is the default behavior, not user error. In a scan of ~22 real ultracode workflow scripts, almost none pinned model: on any stage — even Anthropic's own bundled deep-research workflow pins zero. Reproduce it on your own history in one command:

npx ultracost audit ~/.claude/projects

What ultracost does