Earlier this year we started seeing agent traffic in our logs and it looked like coding agents were calling our CLI. But that CLI wasn't designed with coding agents in mind. We went down a philosophical rabbit hole to see if a CLI is even needed anymore given that Claude, Copilot et al. already follow best practices. Ultimately we decided to create a new CLI from the ground up with coding agents in mind for two reasons:

1. We optimized the CLI for agent callers and cut Claude's output token usage by up to 79% and API cost by up to 67% versus a bare-Claude baseline. We wrote a blog documenting our lessons on optimizing user token usage when designing a CLI, e.g. using predicate flags so the agent doesn't compose jq | python | wc pipelines, output format that strips JSON's redundant field names. The blog is here: https://www.infracost.io/resources/blog/we-cut-claude-s-toke...

2. With cloud costs, precision matters. Telling a coding agent "make this Terraform cost-optimized" can be expensive and lossy. You burn tokens loading code and policy context into every conversation. Your agent could make up a price and you wouldn't know because it's difficult to verify that across the ~10M price points that AWS, Azure and Google have. The CLI runs static analysis on the code, uses the latest prices from cloud vendors, and passes that context to the coding agent.

So that's what we're launching today - Cost.dev: https://cost.dev/.

- It runs locally. Your code never leaves your machine, you get a fast feedback loop, and you're not burning API calls per character when you want to fetch prices.

- The CLI does the deterministic work. Fetching price points, scanning the code, validating fixes. The coding agent does the natural-language part. You don't have to trust the LLM to remember the rules, and can verify it called the right CLI command.

- It provides a consistent rule layer across every tool you use. Get cost estimates in your IDE and your coding agent with a single install. We support Claude Code, GitHub Copilot, Cursor, Windsurf, OpenAI Codex, Gemini CLI, as well as IDEs like VS Code and JetBrains

Before we keep building more in that direction, I want to sanity-check with HN: is "agents writing IaC in prod" actually a thing yet, or am I betting on a future that's still a year out? I know software developers are using coding agents heavily, but are platform/infra folks doing that for prod too? Also, if you have any feedback on Cost.dev, I'd love to hear it!

Comments URL: https://news.ycombinator.com/item?id=48397148

Points: 36

# Comments: 22

Then agent traffic started showing up, and it became clear the 1.0 scope was the right idea aimed at the wrong caller. A human reviewer reads a PR comment; an agent runs `infracost inspect --filter` ... and gets the same insight as a tabular row it can pipe into the next step. So we decided to skip our planned 1.0 release and go for 2.0, where we treated agents as a first-class citizen user of the CLI.

Along the way we picked up some interesting lessons on optimizing user token usage when designing a CLI, and we want to share them with the HN community since other CLI builders might benefit.

Comments URL: https://news.ycombinator.com/item?id=46195045

Points: 12

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Comments URL: https://news.ycombinator.com/item?id=45265633

Points: 3

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Comments URL: https://news.ycombinator.com/item?id=43995381

Points: 4

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I think the easier we make it for engineers to fix tagging issues, the more likely it'll be for engineers to take action. Send me an email asking me to read the company's wiki page on tagging policy and I'll delete the email; tell me I have a typo on line 8 as soon as I open my pull request, I'll fix it and move on.

The testing analogy is a good one as this feature also shows the engineers the current "failing policies" on the main branch too, so whilst they could merge the pull request without fixing the tagging issue, it'll just get added to the list. And maybe like tests, they group them into one task and go through to fix them all every so often to get the main branch back to green!

Comments URL: https://news.ycombinator.com/item?id=36410151

Points: 1

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Comments URL: https://news.ycombinator.com/item?id=32984112

Points: 1

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