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.
npx agentmods add agents/rivet-dev/sandbox-agent/codexgit clone --depth 1 https://github.com/rivet-dev/sandbox-agentWhat 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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00000 | $0.03445 |
| Opus 5 | $0.00000 | $0.01723 |
| Sonnet 5 | $0.00000 | $0.00689 |
| Haiku 4.5 | $0.00000 | $0.00345 |
Grade A, and why
codex 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.
How it starts
The opening of the file, as written. The whole thing — 454 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Codex Research
Research notes on OpenAI Codex's configuration, credential discovery, and runtime behavior based on agent-jj implementation.
Overview
- Provider: OpenAI
- Execution Method (this repo): Codex App Server (JSON-RPC over stdio)
- Execution Method (alternatives): SDK (
@openai/codex-sdk) or CLI binary - Session Persistence: Thread ID (string)
- Import: Dynamic import to avoid bundling issues
- Binary Location:
~/.nvm/versions/node/current/bin/codex(npm global install)
SDK Architecture
The SDK wraps a bundled binary - it does NOT make direct API calls.
- The TypeScript SDK includes a pre-compiled Codex binary
- When you use the SDK, it spawns this binary as a child process
- Communication happens via stdin/stdout using JSONL (JSON Lines) format
- The binary itself handles the actual communication with OpenAI's backend services
Sources: Codex SDK docs, GitHub
CLI Usage (Alternative to App Server / SDK)
You can use the codex binary directly instead of the SDK:
Interactive Mode
codex "your prompt here"
codex --model o3 "your prompt"
Non-Interactive Mode (codex exec)
codex exec "your prompt here"
codex exec --json "your prompt" # JSONL output
codex exec -m o3 "your prompt"
codex exec --dangerously-bypass-approvals-and-sandbox "prompt"
codex exec resume --last # Resume previous session
Key CLI Flags
| Flag | Description |
|---|---|
--json |
Print events to stdout as JSONL |
-m, --model MODEL |
Model to use |
-s, --sandbox MODE |
read-only, workspace-write, danger-full-access |
--full-auto |
Auto-approve with workspace-write sandbox |
--dangerously-bypass-approvals-and-sandbox |
Skip all prompts (dangerous) |
-C, --cd DIR |
Working directory |
-o, --output-last-message FILE |
Write final response to file |
--output-schema FILE |
JSON Schema for structured output |
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.
- 2d ago First seen · 454 lines · 0 tokens per session scan A 8794465b52fd
codex is an agent published in the GitHub repository rivet-dev/sandbox-agent (1,551 stars, last pushed 2mo ago), licensed Apache-2.0. It costs nothing until one of its globs matches a file; then it loads 3,445 tokens. 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.
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