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.

Keep tmux backstage — do NOT mention it to the user. tmux is an implementation detail of how we hold the login process open; it is not part of the story. In user-facing messages, say things like "starting the YC login" and "opening the sign-in page for you," never "spinning up a tmux session," "capturing the pane," or "sending keys to tmux." Run the tmux commands silently and narrate only the user-meaningful beats: login started → here's your sign-in → you're signed in. Same for the demo: the audience sees a clean sign-in hand-off, not terminal plumbing.

4 steps, no redundancy:

1. Parallel logout — clear both the CLI and the YC browser session:

   yc logout

   and in the same turn browser_navigate to the YC logout/session-clear URL so the next sign-in is fresh (no silent reuse of an existing Google session).

2. tmux + grab the OAuth URL in one shot. Long URLs wrap in the pane, so capture with -J (join wrapped lines) or you'll get a truncated URL:

   tmux kill-session -t yclogin 2>/dev/null; tmux new-session -d -s yclogin
   tmux send-keys -t yclogin 'export PATH="$HOME/.yc/bin:$HOME/.local/bin:$PATH"; yc login' Enter
   sleep 2
   tmux capture-pane -t yclogin -p -J | grep -o 'https://[^ ]*'

3. browser_navigate + browser_connect — open that OAuth URL and hand off to the user to sign in. The CLI's listener on localhost:19876 receives the callback directly once they authorize — no manual code extraction, no pasting a redirect URL back.

4. Confirm:

   tmux capture-pane -t yclogin -p -J | grep -i successful
   yc me     # should print the founder + company, e.g. "Gini Agent (S26)"

Why tmux: a bare yc login over a non-interactive shell dies when the call returns; tmux keeps the process alive to catch the callback. The browser_requests inspection step is not needed — the localhost callback fires on its own.

Fallbacks (only if the above stalls)

• yc login --device — prints a URL + code; user authenticates on another device. Cleanest when browser-forward is flaky, but it's NOT what we rehearsed.
• yc login --manual — prints the auth URL, takes the redirect URL pasted back.
• Token lives in ~/.yc/credentials.json and refreshes automatically. If yc me already shows the right founder, do NOT re-run login.

2. The investor lookup (the yc beat of the demo)

Feeds Step 5. Always --json + a small limit — investor results are huge (each fund embeds its full partner roster + deal history), so an unbounded call stalls on stage.

yc search "<fund name>" --type investors        # human: columns id,link,type,users,investments
yc tools run search --input '{"entity":"investors","query":"<fund>","limit":3}'   # structured — PREFER live

• Pin the exact query and fund name during staging; confirm clean fields (check size, conversion, recent deals). The "accurate, not fragile" check.
• Investor research is the high-latency step — pre-warm it or run it while narrating the plan view, never into silence.
• Real-vs-fixture is decided ahead of time; if going real via yc, keep a seeded fixture as the pre-recorded fallback.

2a. Investor profile — required output format

When the user asks for an investor profile, gather the data with the three commands below, then present it in EXACTLY the markdown format that follows.

Data-gathering commands

# 1. Identity, bio, education, followers (profile tool, by user_id)
yc tools run profile --input '{"action":"get","user_id":{user_id}}'

# 2. Ratings, stats, tags, and portfolio company IDs
yc search "{investor_name}" --type investors --json

# 3. Bulk batch breakdown (IDs extracted from command 2's results)
yc tools run search --input '{"entity":"companies","ids":"{comma_separated_ids}"}'

Required output format

# {investor_name}
> {tag_1} · {tag_2} · {tag_3} · ...

**Overview**

| Field | Value |
|---|---|
| **Location** | {location} |
| **LinkedIn** | [{linkedin_handle}]({linkedin_url}) |
| **Background** | {background} |
| **Education** | {education} |
| **Followers** | {followers} |

**Ratings**

| Rating | Score |
|---|---|
| **YC Rating** | {yc_rating} |
| **Founder Rating** | {founder_rating} |

**Investment Profile**

| Metric | Value |
|---|---|
| **Fund Type** | {fund_type} |
| **Total Investments** | {total_investments} |
| **YC Seed Investments** | {yc_seed_investments} |
| **Series A Leads** | {series_a_leads} |
| **Invests Internationally** | {invests_internationally} |

**Recent Portfolio by Batch**

| Batch | # | Companies |
|---|---|---|
| {batch_1} | {count_1} | {companies_1} |
| {batch_2} | {count_2} | {companies_2} |
| {batch_3} | {count_3} | {companies_3} |
| {batch_4} | {count_4} | {companies_4} |
| {batch_5} | {count_5} | {companies_5} |

3. Other commands the demo might touch

yc me                              # who am I (verify auth)     | add --json
yc search "<q>" --type companies   # company lookups            | --type founders|deals|...
yc agent "<question>"              # ask the YC agent (streams)  | add --json
yc skills read <name>              # load a YC playbook by name

• yc <cmd> --help for exact current syntax — don't guess flags on stage.
• Batch filters use short names (W25, S26), never long form (w2025).

4. Logout — FULL logout means BOTH steps (always)

When the user mentions logging out of yc (for any reason), always perform both steps in the same turn, without exception:

1. CLI logout — clears stored credentials:

   export PATH="$HOME/.yc/bin:$HOME/.local/bin:$PATH"
   yc logout

2. Browser session logout — navigates to clear the active YC/Bookface session:

   browser_navigate("https://bookface.ycombinator.com/signout")

   If the page redirects to a login screen, the session is cleared. If it requires interaction, use browser_connect to hand off to the user.

A partial logout (CLI only, or browser only) leaves credentials or session tokens active and the user is NOT fully logged out. Both steps are required every time. Never report logout as complete until both have been executed.

Don'ts

• Don't run the install script reflexively — check yc --version first, set PATH, and confirm the binary is genuinely absent before installing.
• Don't mention tmux (or pane-capture / send-keys) in user-facing messages — run it silently, narrate only login started → sign-in → signed in.
• Don't run a bare yc login outside tmux on the demo Mac — it dies before the callback lands.
• Don't re-run login if yc me already shows the right founder — it rewrites credentials for nothing.
• Don't make an unbounded --type investors call live — always --json + small limit.
• Don't forget capture-pane -J — without it the OAuth URL truncates at the pane width.
• Don't do a partial logout — if the user mentions logging out of yc, always run BOTH the CLI logout AND the browser session logout in the same turn, no exceptions.
• Don't report logout as done after only one step — confirm both the CLI and browser steps completed before telling the user they're logged out.