CLI

@tensorcost/cli estimates and compares LLM prompt costs from a terminal or CI job. It ships with bundled, offline pricing data — no API key or network access required to get a number.

This is a standalone estimation tool, not the way you connect an account to TensorCost. For that, see get started. If you want live cost observability for calls your app is already making, see developer tools.

Install

npm install -g @tensorcost/cli
# or run without installing:
npx @tensorcost/cli <subcommand>

Both tensorcost and tc are registered as binary names after a global install:

tensorcost estimate --prompt "Hello" --model openai/gpt-4o
tc estimate --prompt "Hello" --model openai/gpt-4o

`estimate`

Estimate the cost of a single prompt invocation.

tensorcost estimate \
  --prompt "Summarize the following document in three bullet points." \
  --model anthropic/claude-3-haiku \
  --calls-per-day 5000

Estimated cost : $0.0042 / call
Input tokens   : 1,420
Output tokens  : 284
At 1,000 calls/day: $126.00/month

Flag	Description
`--prompt <text>`	Inline prompt text
`--prompt-file <path>`	Path to a prompt file
`--model <id>`	Model identifier (required) — see `tensorcost models`
`--expected-output-tokens <n>`	Override output token estimate (default: `max(64, input/5)`)
`--calls-per-day <n>`	Also print a monthly cost projection
`--json`	Machine-readable output

`compare`

Compare cost between a baseline and a candidate prompt — useful for a “does my prompt-engineering change cost more?” check before you ship it.

tensorcost compare \
  --baseline-file prompts/v1.txt \
  --candidate-file prompts/v2.txt \
  --model openai/gpt-4o \
  --json

Flag	Description
`--baseline <text>` / `--baseline-file <path>`	Baseline prompt
`--candidate <text>` / `--candidate-file <path>`	Candidate prompt
`--model <id>`	Model identifier (required)
`--expected-output-tokens <n>`	Override output token estimate for both sides
`--json`	Machine-readable output

`models`

List every bundled model and its current rate.

tensorcost models
tensorcost models --json

Covers Anthropic, OpenAI, AWS Bedrock, Google Vertex, and Azure OpenAI model IDs. Run tensorcost models --json for the last_updated field per model — a few less-common models are marked in the CLI’s own output as not yet confirmed against the provider’s pricing page, so check there before relying on those specific figures.

Live rates (optional)

By default everything runs offline against the bundled pricing table. Set TENSORCOST_API_KEY and the CLI fetches live rates — including any negotiated discount on your account — on each invocation, cached for an hour at ~/.tensorcost/rates-cache.json. If the key is absent, the network is unreachable, or the request fails, the CLI falls back to the bundled table silently — offline use is never blocked.

Variable	Description
`TENSORCOST_API_KEY`	API key for live rates from your TensorCost account
`TENSORCOST_BASE_URL`	Override the API base URL — defaults to `https://api.tensorcost.com`

Tokenization

Token counts are estimated using ceil(charCount / 4) by default, accurate to within roughly 10% for typical English text. If tiktoken or @anthropic-ai/tokenizer is installed alongside the CLI, it’s used automatically — no configuration needed.

CI usage

Both estimate and compare accept --json:

result=$(tensorcost estimate --prompt-file prompt.txt --model openai/gpt-4o --json)
total=$(echo "$result" | jq '.totalCostUsd')

A common pattern is a Makefile target that fails a PR if a prompt change costs meaningfully more:

.PHONY: cost-check
cost-check:
	tensorcost compare \
	  --baseline-file $(shell git show main:$(PROMPT)) \
	  --candidate-file $(PROMPT) \
	  --model $(MODEL)

Getting Started

Architecture

Setup

Cloud cost accounts

Features

FinOps Console

Reference

CLI

CLI

Install

`estimate`

`compare`

`models`

Live rates (optional)

Tokenization

CI usage

​CLI

​Install

​estimate

​compare

​models

​Live rates (optional)

​Tokenization

​CI usage

CLI

Install

`estimate`

`compare`

`models`

Live rates (optional)

Tokenization

CI usage