session-historian

session-historian is an agent for Claude Code from George-RD/claude-next-level. It costs 317 tokens per session (1,751 once invoked), scanned A, original, no licence file.

An agent for reading Claude Code session files in JSONL format, where each line stores part of a coding session.

In plain words
What is it for?
Use it in retrospective audits to analyze session history and identify explanations for development gaps.
Why use it?
It helps explain what happened during past sessions by examining their recorded interactions.

Agent for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: model in frontmatter.

Part of the ralph-wiggum-toolkit plugin — 1 skill, 1 command, 4 agents shipped together

Good fit Use it in retrospective audits to analyze session history and identify explanations for development gaps.

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Install with agentmods
npx agentmods add agents/george-rd/claude-next-level/session-historian
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.

Clone the repo
git clone --depth 1 https://github.com/George-RD/claude-next-level

Made for: Claude Code.

Or install ralph-wiggum-toolkit, the plugin that ships this one along with the rest of its 1 skill, 1 command, 4 agents.

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 session-historian

README.md
[![agentmods](https://agentmods.dev/badge/agents/george-rd/claude-next-level/session-historian.svg)](https://agentmods.dev/agents/george-rd/claude-next-level/session-historian)
Your own site
<a href="https://agentmods.dev/agents/george-rd/claude-next-level/session-historian"><img src="https://agentmods.dev/badge/agents/george-rd/claude-next-level/session-historian.svg" alt="Measured on agentmods" height="20"></a>
Per session 317 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,751 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin unknown 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 $0.00317 $0.01751
Opus 5 $0.00159 $0.00875
Sonnet 5 $0.00063 $0.00350
Haiku 4.5 $0.00032 $0.00175

Measured 4d ago against content hash 283cca4ef2e1, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

session-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.

ralph-wiggum-toolkit/recipes/retrospective/agents/session-historian.md · 171 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

Read it on GitHub

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 · 171 lines · 317 tokens per session scan A 283cca4ef2e1

Subscribe to this mod's changes

session-historian is an agent published in the GitHub repository George-RD/claude-next-level (12 stars, last pushed 2mo ago), with no licence file. It adds 317 tokens to every session and 1,751 once invoked, about $0.0016 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 2026-09-03.