yc-cli

yc-cli is a skill for Claude Code, Codex from Open-Curiosity/gini-agent. It costs 69 tokens per session (2,679 once invoked), scanned C, original, MIT.

An operator's guide to the YC command-line tool, which accesses Y Combinator's private Bookface service after login. In this demo, Bookface supplies investor and fund research.

In plain words
What is it for?
Use it when staging or running the Gini batch demo, especially its investor-research step. It covers checking the installation, login, and retrieving fund details used by the demo.
Why use it?
It explains how to check, install, and log in to the command-line tool without assuming the user knows YC, Bookface, or the browser-based authentication process.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/open-curiosity/gini-agent/yc-cli
Any agent
npx skills add Open-Curiosity/gini-agent --skill yc-cli
Clone the repo
git clone --depth 1 https://github.com/Open-Curiosity/gini-agent

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for yc-cli

README.md
[![agentmods](https://agentmods.dev/badge/skills/open-curiosity/gini-agent/yc-cli.svg)](https://agentmods.dev/skills/open-curiosity/gini-agent/yc-cli)
Your own site
<a href="https://agentmods.dev/skills/open-curiosity/gini-agent/yc-cli"><img src="https://agentmods.dev/badge/skills/open-curiosity/gini-agent/yc-cli.svg" alt="Measured on agentmods" height="20"></a>
Per session 69 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,679 The whole file, excluding the scripts and references it only reads on demand.
Security scan C 2 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00069 $0.02679
Opus 5 $0.00034 $0.01340
Sonnet 5 $0.00014 $0.00536
Haiku 4.5 $0.00007 $0.00268

Measured 4d ago against content hash 5d3622930611, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade C, and why

yc-cli scanned grade C with 2 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 4d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Downloads and executes remote codehighSupply chain

curl | sh runs whatever the server returns today, which is not necessarily what it returned when this was reviewed.

curl -fsSL https://bookface.ycombinator.com/cli/install.sh | bash

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

curl -fsSL https://bookface.ycombinator.com/cli/install.sh | bash
skills/integrations/yc-cli/SKILL.md · 232 lines

How it starts

The opening of the file, as written. The whole thing — 232 lines — stays where its author put it; the contents beside it link to each section on GitHub.

YC CLI (yc) — demo operator's guide

yc is the Y Combinator CLI; it talks to Bookface over an authenticated API. In our demo it's the investor-research source behind Step 5: pulling a fund's track record (check size, YC conversion, recent deals) from the terminal. This guide covers only the parts the demo touches.

0. Install + PATH (do this first)

Before using yc, check whether it's installed and decide whether to install it — you (the agent) own this judgment; don't blindly run an install.

  1. Check if it's available. Put the usual install locations on PATH first, since the binary often isn't there in a non-interactive shell, then look:

    export PATH="$HOME/.yc/bin:$HOME/.local/bin:$PATH"
    yc --version   # or: ycp --version
    

    If that prints a version, it's installed — skip to login. If it errors with "command not found", continue.

  2. Confirm it's genuinely missing, not just off PATH. A bare yc can fail just because PATH wasn't set. Before installing, verify the binary truly isn't on disk (e.g. check ~/.yc/bin/yc and ~/.local/bin/yc). Only if it's actually absent do you install.

  3. Install only when missing:

    curl -fsSL https://bookface.ycombinator.com/cli/install.sh | bash
    

    Then re-export PATH (step 1) so the current shell sees the new binary, and re-run yc --version to confirm.

Notes:

  • If an existing yc command was detected at install time, the CLI may be installed as ycp instead — try ycp if yc is absent.
  • Non-interactive SSH shells don't source ~/.zshrc, so set the export PATH=... line at the top of any script before calling yc.

1. The optimal login flow (VALIDATED — use this)

We are NOT logged in yet. This is the flow we rehearsed to convergence — it's the demo's Step 5 trust beat: the agent forwards its browser to the user, the user signs in on their own device, the agent never sees the password. yc login spins a local callback listener on localhost:19876; the agent's forwarded browser can't reach that localhost, so we keep yc login alive in tmux and let the CLI catch the callback directly while the user signs in.

Read the full file on GitHub · 232 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 4d ago First seen · 232 lines · 69 tokens per session scan C 5d3622930611

Subscribe to this mod's changes

yc-cli is a skill published in the GitHub repository Open-Curiosity/gini-agent (1,869 stars, last pushed 1mo ago), licensed MIT. It adds 69 tokens to every session and 2,679 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it C with 2 findings (downloads and executes remote code, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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