jeff-code: Instructions file for Codex

AGENTS.md

jeff-code AGENTS.md is an instructions file for Codex, OpenCode from firelex/jeff-code. It costs 1,972 tokens per session, scanned A, original, MIT.

Repository instructions for the jeff-code project covering coding rules, communication style, dependency safety, and development practices. An AGENTS.md file is a set of local rules for coding agents working in a repository.

In plain words
What is it for?
Use it while modifying the repository to guide code quality, explanations, commands, dependency choices, and responses to user feedback.
Why use it?
It gives the agent project-specific constraints, such as reading files fully, keeping technical answers direct, and avoiding unsafe dependency or code changes.

Instructions file for CodexOpenCode

Written for Codex and OpenCode: the file is AGENTS.md.

This is firelex/jeff-code's own configuration. It tells Codex and OpenCode how to work on jeff-code itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything jeff-code configures →

Reuse

Borrowing it

Nothing to install: this file belongs to firelex/jeff-code. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/firelex/jeff-code/main/AGENTS.md
Clone the repo
git clone --depth 1 https://github.com/firelex/jeff-code

Made for: Codex, OpenCode.

Wrote this? Show the measurements

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Per session 1,972 This file is loaded in full into every session.
When invoked 1,972 The same file — it is already loaded in full.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.01972 $0.01972
Opus 5.5 $0.00789 $0.00789
Sonnet 5.5 $0.00394 $0.00394
Haiku 4.5 $0.00197 $0.00197

Measured 23d ago against content hash fe7c40275593, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

jeff-code 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 23d 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 · 126 lines

How it starts

The opening of the file, as written. The whole thing — 126 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Development Rules

Conversational Style

  • Keep answers short and concise
  • No emojis in commits, issues, PR comments, or code
  • No fluff or cheerful filler text (e.g., "Thanks @user" not "Thanks so much @user!")
  • Technical prose only, be direct
  • Use concise, clear, simple language. Define unavoidable jargon before using it.
  • Explain non-trivial designs and problems as: problem, concrete example or short trace, then solution. State why the solution is necessary and distinguish it from optional complexity.
  • Prefer concrete behavior and small illustrations over abstract summaries, dense terminology, or unexplained lists of changes.
  • When the user asks a question, answer it first before making edits or running implementation commands.
  • When responding to user feedback or an analysis, explicitly say whether you agree or disagree before saying what you changed.

Code Quality

  • Read files in full before wide-ranging changes, before editing files you have not fully inspected, and when asked to investigate or audit. Do not rely on search snippets for broad changes.
  • No any unless absolutely necessary.
  • Inline single-line helpers that have only one call site.
  • Check node_modules for external API types; don't guess.
  • No inline imports (await import(), import("pkg").Type, dynamic type imports). Top-level imports only.
  • In packages/coding-agent, resolve package assets through helpers in src/config.ts. Do not use __dirname directly; the helpers account for source checkouts, npm installations, and standalone binaries.
  • Never remove or downgrade code to fix type errors from outdated deps; upgrade the dep instead.
  • Use only erasable TypeScript syntax (Node strip-only mode) in code checked by the root config (packages/*/src, packages/*/test, packages/coding-agent/examples): no parameter properties, enum, namespace/module, import =, export =, or other constructs needing JS emit. Use explicit fields with constructor assignments.
  • Always ask before removing functionality or code that appears intentional.
  • Do not preserve backward compatibility unless the user asks for it.
  • Never hardcode key checks (e.g. matchesKey(keyData, "ctrl+x")). Add defaults to DEFAULT_EDITOR_KEYBINDINGS or DEFAULT_APP_KEYBINDINGS so they stay configurable.
  • Never modify packages/ai/src/models.generated.ts directly; update packages/ai/scripts/generate-models.ts instead, then regenerate. Including the resulting models.generated.ts diff is always OK, even if regeneration includes unrelated upstream model metadata changes.

Read the full file on GitHub · 126 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. 23d ago First seen · 126 lines · 1,972 tokens per session scan A fe7c40275593

Subscribe to this mod's changes

jeff-code AGENTS.md is an instructions file published in the GitHub repository firelex/jeff-code (32 stars, last pushed 1mo ago), licensed MIT. It adds 1,972 tokens to every session, about $0.0079 per session on Opus 5.5. 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 2026-10-14.

Related

jeff-code AGENTS.md compared with instructions from other repositories

jeff-code AGENTS.md next to 6 instructions from other repositories
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jeff-code AGENTS.mdfirelex/jeff-codeInstructions file321mo agoMITA1,972Codex, OpenCode
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vscode copilot-instructions.mdmicrosoft/vscodeInstructions file195kyesterdayMITA3,093GitHub Copilot
deepseek-harness AGENTS.mddeepseek-ai/deepseek-harnessInstructions file274k2d agoMITA4,313Codex, OpenCode