codex-history: Instructions file for Codex

AGENTS.md

codex-history AGENTS.md is an instructions file for Codex, OpenCode from nishantdesai/codex-history. It costs 500 tokens per session, scanned A, original, MIT.

Repository instructions for codex-history, a Rust command-line tool that reads and searches locally stored Codex session history. They define the project's boundaries and design choices.

In plain words
What is it for?
Building and maintaining local session-history parsing, optional indexing, tests, typed errors, and narrowly focused Rust modules.
Why use it?
They keep the tool read-only and stop changes from depending on private interfaces or real personal history data. They also guide architecture and testing decisions.

Instructions file for CodexOpenCode

Written for Codex and OpenCode: the file is AGENTS.md. Also seen: mentions AGENTS.md; mentions Codex.

This is nishantdesai/codex-history's own configuration. It tells Codex and OpenCode how to work on codex-history 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 codex-history configures →

Reuse

Borrowing it

Nothing to install: this file belongs to nishantdesai/codex-history. 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/nishantdesai/codex-history/main/AGENTS.md
Clone the repo
git clone --depth 1 https://github.com/nishantdesai/codex-history

Made for: Codex, OpenCode.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for codex-history AGENTS.md

README.md
[![agentmods](https://agentmods.dev/badge/instructions/nishantdesai/codex-history/agents-md.svg)](https://agentmods.dev/instructions/nishantdesai/codex-history/agents-md)
Your own site
<a href="https://agentmods.dev/instructions/nishantdesai/codex-history/agents-md"><img src="https://agentmods.dev/badge/instructions/nishantdesai/codex-history/agents-md.svg" alt="Measured on agentmods" height="20"></a>
Per session 500 This file is loaded in full into every session.
When invoked 500 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 $0.00500 $0.00500
Opus 5 $0.00250 $0.00250
Sonnet 5 $0.00100 $0.00100
Haiku 4.5 $0.00050 $0.00050

Measured 7d ago against content hash e89ebda7718e, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

codex-history 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 7d 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 · 66 lines

How it starts

The opening of the file, as written. The whole thing — 66 lines — stays where its author put it; the contents beside it link to each section on GitHub.

AGENTS.md

Purpose

This repository builds codex-history, a Rust CLI for querying locally accessible Codex session history.

Source of truth

When making architectural or scope decisions, follow:

  1. docs/SPEC.md
  2. README.md
  3. docs/RELEASING.md

If these documents conflict, prefer the more conservative interpretation and do not widen scope.

Core implementation decision

Use direct local Codex history/session-log parsing as the primary source of truth.

Do not implement the App Server adapter in the initial build. Keep the code structure compatible with a later adapter, but defer that work until after the local-first tool is working.

Working rules

  • Keep the tool read-only
  • Do not add any feature that mutates Codex history
  • Do not depend on undocumented private endpoints
  • Prefer local backend first and primary
  • Keep App Server integration deferred until later
  • Keep the index opt-in
  • Use synthetic fixtures only
  • Do not check in real history data, indexes, or machine-specific paths

Code quality rules

  • prefer small, reviewable commits
  • add tests for each feature
  • keep modules narrowly scoped
  • use explicit errors and typed results
  • avoid introducing async complexity unless clearly necessary
  • preserve unknown item/event variants instead of discarding them

Output and UX rules

  • stdout for successful command output
  • stderr for diagnostics and errors
  • never mix prose into --json output
  • make --help text concise and accurate
  • keep --json and --ndjson as the machine-facing interfaces for search/grep
  • keep human-readable search/grep output aligned with the implemented modes: default output is grouped by thread with per-hit full text blocks, and --compact is a markdown-table-style one-line view that should not deliberately truncate thread name, cwd, or preview text

Packaging rules

  • binary name must remain codex-history
  • repository license is MIT unless the user explicitly changes it
  • release artifacts must be compatible with the Homebrew tap at github.com/nishantdesai/homebrew-tap

Read the full file on GitHub · 66 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. 7d ago First seen · 66 lines · 500 tokens per session scan A e89ebda7718e

Subscribe to this mod's changes

codex-history AGENTS.md is an instructions file published in the GitHub repository nishantdesai/codex-history (9 stars, last pushed 5mo ago), licensed MIT. It adds 500 tokens to every session, about $0.0025 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 2026-08-31.

Related

Other instructions, from other repositories

next.js AGENTS.md

AGENTS.md instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.

vercel/next.js · 7,296 tokens

codex AGENTS.md

AGENTS.md instructions for openai/codex, covering rust/codex-rs, the codex-core crate, code review rules, crate api surface and model visible context.

openai/codex · 5,182 tokens

vscode buildNext.instructions.md

Working notes and architecture documentation for the new esbuild-based build system in build/next. Use when making changes to the new build pipeline (transpile/bundle commands, NLS plugin, source-map handling, resource copying, or self-hosting watch tasks).

microsoft/vscode · 6,785 tokens

vscode oss-third-party-notices.instructions.md

Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, applying the notice (cutover) and fallback chain (never fail the build).

microsoft/vscode · 5,001 tokens

langchain AGENTS.md

AGENTS.md instructions for langchain-ai/langchain, covering global development guidelines for the langchain monorepo, corridor security analysis, project architecture and context, monorepo structure and development tools & commands.

langchain-ai/langchain · 4,469 tokens

spec-kit AGENTS.md

AGENTS.md instructions for github/spec-kit, covering agents.md, about spec kit and specify, quickstart — add a new integration in 5 steps, integration architecture and integrationmanifest — file tracking.

github/spec-kit · 7,104 tokens