Borrowing it
Nothing to install: this file belongs to davidmatousek/tachi. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/davidmatousek/tachi/main/.claude/agents/_AGENT_BEST_PRACTICES.mdgit clone --depth 1 https://github.com/davidmatousek/tachiWrote 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.
[](https://agentmods.dev/agents/davidmatousek/tachi/_agent_best_practices)<a href="https://agentmods.dev/agents/davidmatousek/tachi/_agent_best_practices"><img src="https://agentmods.dev/badge/agents/davidmatousek/tachi/_agent_best_practices/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.
<a href="https://agentmods.dev/agents/davidmatousek/tachi/_agent_best_practices"><img src="https://agentmods.dev/badge/agents/davidmatousek/tachi/_agent_best_practices.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00000 | $0.07408 |
| Opus 5.5 | $0.00000 | $0.02963 |
| Sonnet 5.5 | $0.00000 | $0.01482 |
| Haiku 4.5 | $0.00000 | $0.00741 |
Grade A, and why
_AGENT_BEST_PRACTICES 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 1mo 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.
Copies of this mod
1 near-identical copy found in the catalogue:
- _AGENT_BEST_PRACTICES — 100% identical, 0 lines differ
How it starts
The opening of the file, as written. The whole thing — 1,003 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Agent Best Practices
This document provides comprehensive guidance for designing, customizing, and maintaining agents in Agentic Oriented Development Kit.
Table of Contents
- Core Principles
- Standard Agent Structure
- Metadata Specification
- Quality Checklist
- Preservation-First Enhancement
- Template Variables
- Common Patterns
- Examples
1. Core Principles
All agents in Agentic Oriented Development Kit follow eleven core principles. Principles 1-8 are foundational. Principles 9-11 are inspired by the 12-Factor Agents methodology and target production resilience.
Principle 1: Conciseness
Target: 150-250 lines optimal, 300 lines maximum (with documented justification)
Why: Large agent files cause slow context loading and high token consumption. Concise agents load faster and respond more quickly.
How to achieve:
- Remove redundant explanations
- Replace verbose paragraphs with bullet points
- Move code examples to skill references
- Eliminate obvious or self-explanatory content
Example:
# Bad (verbose)
When you need to review the architecture of a system, you should first
carefully examine all the components and understand how they interact
with each other. This involves looking at the database layer, the API
layer, the frontend components, and any external services.
# Good (concise)
Architecture review steps:
- Examine component interactions (database, API, frontend, external services)
- Identify integration points
- Validate against system requirements
Principle 2: Structure
Target: All agents use identical 8-section format
Why: Consistent structure enables predictable navigation, easier customization, and automated validation. Template adopters know exactly where to find information.
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.
- 1mo ago First seen · 1,003 lines · 0 tokens per session scan A 2096d5c5dbb2
_AGENT_BEST_PRACTICES is an agent published in the GitHub repository davidmatousek/tachi (94 stars, last pushed 2d ago), licensed Apache-2.0. It costs nothing until one of its globs matches a file; then it loads 7,408 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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