heygen-cli AGENTS.md

A set of project instructions for developing the HeyGen command-line tool, a Go program for using HeyGen’s video API from a terminal.

In plain words
What is it for?
It is for contributors working on the HeyGen CLI, especially when changing commands, running tests, or updating it from an OpenAPI specification.
Why use it?
It keeps generated code separate from hand-written code and explains the correct commands for building, testing, linting, and regenerating the command interface.

Instructions file for CodexOpenCode

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 instructions/heygen-com/heygen-cli/agents-md
Clone the repo
git clone --depth 1 https://github.com/heygen-com/heygen-cli

Made for: Codex, OpenCode.

Per session 1,750 This file is loaded in full into every session.
When invoked 1,750 The same file — it is already loaded in full.
Security scan A 0 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 $0.01750 $0.01750
Opus 5 $0.00875 $0.00875
Sonnet 5 $0.00350 $0.00350
Haiku 4.5 $0.00175 $0.00175

Measured 2d ago against content hash 2c524c4df124, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

heygen-cli AGENTS.md scanned grade A with 0 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 2d 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.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

AGENTS.md · 91 lines

How it starts

The opening of the file, as written. The whole thing — 91 lines — stays where its author put it; the contents beside it link to each section on GitHub.

HeyGen CLI

Go CLI wrapping HeyGen's v3 API. Built on Cobra, command surface auto-generated from OpenAPI spec.

Build & Test

make build    # → bin/heygen
make test     # all tests are mocked, no API key needed
make lint     # golangci-lint
make clean
make generate SPEC=path/to/spec.json  # regenerate gen/ from OpenAPI spec

Smoke test against real API: HEYGEN_API_KEY=<key> ./bin/heygen video list --limit 2

For project layout and development guide, see CONTRIBUTING.md. For branch names, commit messages, and PR titles, see .github/GIT_CONVENTIONS.md.

Key Rules

gen/ is generated — never hand-edit

Files in gen/ are deleted and regenerated by make generate. Never put hand-written logic there. Hand-written enhancements (column definitions, flag constraints, custom commands) go in cmd/heygen/.

command.Spec is immutable

Spec is a generated, read-only definition. Never mutate it at runtime. Column definitions, poll configs, and other runtime enhancements are external lookup data in cmd/heygen/, passed to the formatter or builder as separate arguments.

Cobra command tree is single-use

newRootCmd() builds a fresh Cobra command tree for each CLI invocation. Command instances are never reused across executions — each main() call and each test creates a new tree. This is load-bearing: the builder's PreRunE mutates Cobra flag annotations to bypass required-flag validation for --request-schema / --response-schema.

Codegen requires examples

make generate warns if any command lacks examples but still generates the code. Use make generate STRICT=1 locally to fail on missing examples. A test in cmd/heygen/generated_examples_test.go enforces that every generated command has at least one example, so make test (and CI) will fail if examples are missing. Examples live in codegen/examples/{group}.yaml.

Codegen command naming

A command name is the path segments after the group root plus a terminal verb derived from the HTTP method. A group has at most one primary root — the one that restates the group name — and only that root is dropped. Every other root stays as a sub-group, minus the group prefix, which is why one OpenAPI tag can span several resources without any override: Brand covers both /v3/brand-kits and /v3/brand-glossaries, giving brand kits list and brand glossaries get. An umbrella group like that has no primary root, which is correct — don't add one to groupPrimaryRoots to force it.

Read the full file on GitHub · 91 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. 2d ago First seen · 91 lines · 1,750 tokens per session scan A 2c524c4df124

Subscribe to this mod's changes

heygen-cli AGENTS.md is an instructions file published in the GitHub repository heygen-com/heygen-cli (113 stars, last pushed 3d ago), licensed Apache-2.0. It adds 1,750 tokens to every session, about $0.0088 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.