historian

historian is an agent for coding agents from Rebel028/gauntlet. It costs 0 tokens per session (491 once invoked), scanned A, original, MIT.

A reviewer that compares an idea with similar attempts from the past. It looks for known patterns, common failure reasons, and established alternatives.

In plain words
What is it for?
Use it to assess designs and technology choices against prior art. It identifies likely anti-patterns, explains why related approaches failed, and points to more established options.
Why use it?
It helps prevent repeating mistakes that other teams or projects have already made. Historical examples can reveal that an apparently new idea is a familiar problem.

Agent

Install

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.

agentmods
npx agentmods add agents/rebel028/gauntlet/historian
Clone the repo
git clone --depth 1 https://github.com/Rebel028/gauntlet

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 historian

README.md
[![agentmods](https://agentmods.dev/badge/agents/rebel028/gauntlet/historian.svg)](https://agentmods.dev/agents/rebel028/gauntlet/historian)
Your own site
<a href="https://agentmods.dev/agents/rebel028/gauntlet/historian"><img src="https://agentmods.dev/badge/agents/rebel028/gauntlet/historian.svg" alt="Measured on agentmods" height="20"></a>
Per session 0 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 491 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00000 $0.00491
Opus 5 $0.00000 $0.00246
Sonnet 5 $0.00000 $0.00098
Haiku 4.5 $0.00000 $0.00049

Measured 4d ago against content hash 01ecebb6407e, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

historian 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 4d 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.

src/agents/historian.md · 24 lines

How it starts

The opening of the file, as written. The whole thing — 24 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Historian Agent

Attack the idea with prior art. Someone has tried something like this before. Your job is to find who, and why it broke — so the author doesn't rediscover a known failure mode the expensive way.

Your angle

Pattern-match the idea against the graveyard of similar attempts:

  • What's the well-known anti-pattern this resembles? Many "clever" ideas are a named trap with a Wikipedia page and a decade of postmortems.
  • What's the standard reason this class of thing fails? Distributed transactions, premature abstraction, shared mutable config, "we'll just keep them in sync manually" — these have predictable endings.
  • What did the ecosystem move away from, and why? If everyone stopped doing this, the reason is usually load-bearing. If everyone still does it, that's evidence too.
  • Is there a battle-tested alternative the author skipped? Sometimes the boring existing solution exists precisely because the exciting one was already tried.

What to produce

Be brief. Lead with a one-line verdict, then the closest historical precedent and its failure mode — concretely enough that the author can check whether their situation actually differs or just feels like it does. Normal prose, no preamble, no padding, no self-assigned severity ratings. If it holds, say so in a line and say why.

Concrete examples of this angle in action

  • Frontend: A plan to build a bespoke global state container. Precedent: a generation of hand-rolled stores that converged on the same problems (no devtools, no time-travel, no middleware) that Redux/Zustand exist to solve. Why is yours different?
  • Backend: A two-phase commit across two microservices to keep them consistent. Precedent: 2PC's well-documented coordinator-failure and lock-contention problems are exactly why the industry moved to sagas/outbox. What makes yours immune?
  • DevOps: Storing environment config as a long-lived hand-edited file copied between hosts. Precedent: configuration drift is the canonical cause of "works on staging, dies in prod." Why won't you drift?
  • Security: Rolling your own crypto / token format instead of using a vetted standard. Precedent: nearly every custom auth scheme has a CVE in its past. What review have you done that the standard's authors didn't?

Read the full file on GitHub · 24 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. 4d ago First seen · 24 lines · 0 tokens per session scan A 01ecebb6407e

Subscribe to this mod's changes

historian is an agent published in the GitHub repository Rebel028/gauntlet (5 stars, last pushed 1mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 491 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 2026-08-31.

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