What is start-session?

A command for starting a focused learning session inside an agentic-study-environment study project. It helps choose a topic and decide whether to learn through explanation, practice, or another supported session format.

Use it to study a topic, work through an exercise, practise a skill, or begin a domain-specific session such as a simulation or defence exercise.

It gives a study session a clear topic, beginning, and structure instead of leaving learning unplanned. It also loads the project's existing instructions and progress.

start-session — Skill for Claude Code by TimboGP

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.

Any agent

npx skills add TimboGP/timbogp-marketplace --skill start-session

Clone the repo

git clone --depth 1 https://github.com/TimboGP/timbogp-marketplace

Made for: Claude Code.

Or install agentic-study-environment, the plugin that ships this one along with the rest of its 7 skills, 1 command.

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/skills/timbogp/timbogp-marketplace/start-session/github.svg)](https://agentmods.dev/skills/timbogp/timbogp-marketplace/start-session)

Your own site

<a href="https://agentmods.dev/skills/timbogp/timbogp-marketplace/start-session"><img src="https://agentmods.dev/badge/skills/timbogp/timbogp-marketplace/start-session/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/skills/timbogp/timbogp-marketplace/start-session"><img src="https://agentmods.dev/badge/skills/timbogp/timbogp-marketplace/start-session.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 144 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,789 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 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	$0.00144	$0.01789
Opus 5	$0.00072	$0.00894
Sonnet 5	$0.00029	$0.00358
Haiku 4.5	$0.00014	$0.00179

Measured 11d ago against content hash 127fb2408772, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

start-session 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 11d 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.

plugin/agentic-study-environment/skills/start-session/SKILL.md · 79 lines

How it starts

The opening of the file, as written. The whole thing — 79 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Start a learning session

This skill begins a bracketed session inside a learning sub-project. A session is the unit of work in the harness: it has a start (this skill), a focus (one topic, one session type), and an end (stop-session). Progress is recorded at session end.

When to use

The user wants to actively study something. They might say "start session", "let's work on TASEP", "begin a practice session on derivatives", or just "I want to do an exercise on Y". Anything that signals "tutor me through a topic now" should match.

If the user has not bootstrapped a sub-project yet, redirect them to the bootstrap skill first.

What to read before doing anything else

Before proposing or conducting anything, load context:

The harness's optional .studyenv/AGENTS.md if present, otherwise .studyenv/CLAUDE.md if present (for cross-project conventions and any global Language:), and .studyenv/PROGRESS.md (created by bootstrap on first use). Both are optional context; if either is missing, continue without it. Everything the harness generates lives under .studyenv/ — the host project's own files are not read or modified.
The sub-project's .studyenv/<name>/AGENTS.md, falling back to .studyenv/<name>/CLAUDE.md for older projects (for Domain:, Language:, goals, Tools & Materials), and .studyenv/<name>/PROGRESS.md (for what's been covered and at what status).
The sub-project's .studyenv/<name>/ai-agent-materials/ — especially curriculum.md and any concept maps / excerpts. If there are unanalyzed items in .studyenv/<name>/source-materials/, analyze them now and write the intermediate representations into ai-agent-materials/ before proposing a route.
If the sub-project declares Domain:, load the matching overlay at ../../domains/<domain>.md (relative to this SKILL.md). The overlay refines the generic rules in this skill — it does not replace them. If no Domain: is set, or Domain: study, no overlay applies and the neutral defaults stand.

Read the full file on GitHub · 79 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.

11d ago First seen · 79 lines · 144 tokens per session scan A 127fb2408772

Subscribe to this mod's changes

start-session is a skill published in the GitHub repository TimboGP/timbogp-marketplace (3 stars, last pushed 2mo ago), licensed MIT. It adds 144 tokens to every session and 1,789 once invoked, about $0.0007 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.

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