What is kit AGENTS.md?

A set of coding instructions for the Kit project, including build and test commands, code style, architecture, and rules for its public Go library.

Use it when developing Kit to run builds, tests, linting, and formatting, and to follow its conventions for errors, logging, JSON, contexts, providers, tools, extensions, and the terminal interface.

It gives contributors consistent practices for checking, formatting, structuring, and extending the Kit codebase.

How mark3labs/kit configures Codex and OpenCode

Reuse

Borrowing it

Nothing to install: this file belongs to mark3labs/kit. 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/mark3labs/kit/master/AGENTS.md

Clone the repo

git clone --depth 1 https://github.com/mark3labs/kit

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.

README.md

[![agentmods](https://agentmods.dev/badge/instructions/mark3labs/kit/agents-md/github.svg)](https://agentmods.dev/instructions/mark3labs/kit/agents-md)

Your own site

<a href="https://agentmods.dev/instructions/mark3labs/kit/agents-md"><img src="https://agentmods.dev/badge/instructions/mark3labs/kit/agents-md/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/instructions/mark3labs/kit/agents-md"><img src="https://agentmods.dev/badge/instructions/mark3labs/kit/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 2,222 This file is loaded in full into every session.

When invoked 2,222 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.

Model	Per session	Once invoked
Fable 5.1	$0.02222	$0.02222
Opus 5.5	$0.00889	$0.00889
Sonnet 5.5	$0.00444	$0.00444
Haiku 4.5	$0.00222	$0.00222

Measured 20d ago against content hash 9e7eab833660, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

kit 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 20d 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 · 145 lines

How it starts

The opening of the file, as written. The whole thing — 145 lines — stays where its author put it; the contents beside it link to each section on GitHub.

KIT Agent Guidelines

Always talk in ASD-STE100 Simplified Technical English

Build/Test Commands

Build: go build -o output/kit ./cmd/kit
Test all: go test -race ./...
Test single: go test -race ./cmd -run TestScriptExecution
Lint: go vet ./...
Format: go fmt ./...
Nix: nix build .#default builds the pinned release (see flake.nix); nix develop gives go/gopls/golangci-lint. After a release, bump the pin with scripts/bump-flake-release-pin.sh vX.Y.Z, then scripts/update-flake-vendor-hash.sh if dependencies moved.

Code Style

Imports: stdlib → third-party → local (blank lines between)
Naming: camelCase (unexported), PascalCase (exported)
Errors: Always check, wrap with fmt.Errorf("context: %w", err)
Logging: Use github.com/charmbracelet/log structured logging
Types: Prefer any over interface{}
JSON: snake_case tags with omitempty where appropriate
Context: First parameter for blocking operations

Architecture

Multi-provider LLM support via llm.Provider interface
MCP client-server for tool integration
Builtin servers: bash, fetch, todo, fs
Extension system (internal/extensions/): Yaegi-interpreted Go, 13 lifecycle events, custom tools/commands/widgets/overlays/editor interceptors
TUI (internal/ui/): Bubble Tea v2 parent-child model (AppModel → InputComponent, StreamComponent, etc.)
Decoupling pattern: cmd/root.go has converter functions (e.g. widgetProviderForUI()) that bridge internal/extensions/ types to internal/ui/ types — the UI never imports extensions directly
Public SDK (pkg/kit/): The public-facing Go SDK for embedding Kit as a library. See rules below.
Code mode (internal/codemode/ engine, internal/core/codemode.go tool): default-on codemode core tool runs model-written JavaScript in goja. It implements core.ToolSetObserver: Agent.composeModelTools() hands it the full wrapped tool set each step (so nested calls pass through extension/SDK hooks) and drops tools whose exposure hides them from the model. Never use Yaegi for model-written code (see gotchas below).

Read the full file on GitHub · 145 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.

20d ago Changed 9e7eab833660
1mo ago Changed · +4 lines · +84 tokens per session 7a18e138ee38
1mo ago Changed · +1 lines · +100 tokens per session 4c987b3fb4f5
2mo ago Changed · +11 lines · +247 tokens per session 92ec558fce25
2mo ago First seen · 129 lines · 1,791 tokens per session scan A d345be63612d

Subscribe to this mod's changes

kit AGENTS.md is an instructions file published in the GitHub repository mark3labs/kit (152 stars, last pushed 4d ago), licensed MIT. It adds 2,222 tokens to every session, about $0.0089 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 2026-08-30.

kit AGENTS.md next to 6 instructions from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
kit AGENTS.mdmark3labs/kit	Instructions file	152	4d ago	MIT	A	2,222	Codex, OpenCode
vscode buildNext.instructions.mdmicrosoft/vscode	Instructions file	195k	today	MIT	A	9,719	GitHub Copilot
next.js AGENTS.mdvercel/next.js	Instructions file	143k	today	MIT	A	7,461	Codex, OpenCode
vscode oss-third-party-notices.instructions.mdmicrosoft/vscode	Instructions file	195k	today	MIT	A	5,516	GitHub Copilot
langchain AGENTS.mdlangchain-ai/langchain	Instructions file	149k	yesterday	MIT	A	4,680	Codex, OpenCode
vscode copilot-instructions.mdmicrosoft/vscode	Instructions file	195k	today	MIT	A	3,093	GitHub Copilot
vscode ai-customization.instructions.mdmicrosoft/vscode	Instructions file	195k	today	MIT	A	1,907	GitHub Copilot

kit: Instructions file for Codex