roundel/terminal

Two questions about the terminal that are not colour, and that three packages in the family were each answering by hand (R12).

• Is anybody there to type? caique/decide asked isTTY.stdin && !CI and missed the agent case entirely: under Claude Code a prompt has a terminal and no person, and a prompt that waits there hangs the agent that ran it. burgee's own detectAgent knew that; caique did not ask it.
• Can it draw a tick? flagstaff/ora carried is-unicode-supported whole, and caique/inquirer a four-condition subset that answered differently on the Linux console and on half the Windows terminals the full table names.

Both read a runtime passed in, never the process (R9), and neither reaches another module, so roundel/terminal costs only itself. It is its own subpath rather than more of roundel/policy because ./chalk stands on policy.js and R8 caps that whole graph at chalk 6.0.0's own bytes, with 7 of them to spare.

import { unicode, AGENTS, interactive } from 'roundel/terminal';

FunctionsCopy Anchor Link

unicodeCopy Anchor Link

Whether the terminal can be expected to draw non-ASCII glyphs — is-unicode-supported 2.1.0, condition for condition. Everything but Windows is yes, except the Linux console (TERM=linux), whose font has no ticks; on Windows only the terminals the incumbent names.

This is the one place roundel reads TERM_PROGRAM and the platform. The refusal in the spec is about colour — the level is decided by the user's instruction and TERM, never an emulator allow-list — and a glyph table is not a colour level.

function unicode({ env, platform }: Glyphs): boolean;

Returns boolean

ConstantsCopy Anchor Link

AGENTSCopy Anchor Link

The variables whose presence says an agent is driving the process — the list burgee/src/agent.ts probes (N12), after @vercel/detect-agent. AI_AGENT is the generic one any agent can set.

const AGENTS: readonly ["AI_AGENT", "CLAUDECODE", "CURSOR_AGENT", "CODEX_THREAD_ID", "GEMINI_CLI"];

interactiveCopy Anchor Link

Whether a person can be asked something and be expected to answer.

FORCE_TTY=1 says yes outright, as it does to burgee's detectAgent: it is the one explicit instruction, and a caller who pipes answers into a prompt on purpose sets it. Otherwise it takes a terminal on stdin, no CI, and no agent variable. An agent may well have a terminal; what it does not have is a person.

const interactive: ({ env, isTTY }: Terminal) => boolean;

InterfacesCopy Anchor Link

GlyphsCopy Anchor Link

The slice unicode reads: the environment and the platform, process.platform's spelling.

interface Glyphs {
    env: Record<string, string | undefined>;
    platform?: string;
}

TerminalCopy Anchor Link

The slice of a runtime interactive reads. burgee's and caique's runtimes both satisfy it.

interface Terminal {
    env: Record<string, string | undefined>;
    isTTY: {
        stdin: boolean;
    };
}