SessionStart

A hook that runs when a coding-agent session starts. It executes the project's `install.sh` script with a format option.

In plain words
What is it for?
Starting a session by running `install.sh --format`.
Why use it?
It automates the setup step needed at the beginning of a session.

Hook

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 hooks/twowells/catenary/session-start
Clone the repo
git clone --depth 1 https://github.com/TwoWells/Catenary
Per session not measured What this adds to a session before it is invoked.
When invoked not measured Not applicable: nothing here is loaded into a session.
Security scan C 2 findings. Scan, not verified.
Origin unknown No closer match found in the catalogue.
Security

Grade C, and why

SessionStart scanned grade C with 2 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 yesterday.

A static scan of the commands this hook runs, not an audit. A hook is shell that executes on your machine at the event it names, which is why every command in it is printed with what was found.

Downloads and executes remote codehighSupply chain

curl | sh runs whatever the server returns today, which is not necessarily what it returned when this was reviewed.

"command": "catenary hook session-start --format=claude || { (notify-send Catenary 'catenary binary not found on PATH. Install it, then start a new session.' || osascript -e 'display notification \"catenary binary not fo

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

"command": "catenary hook session-start --format=claude || { (notify-send Catenary 'catenary binary not found on PATH. Install it, then start a new session.' || osascript -e 'display notification \"catenary binary not fo
plugins/catenary/hooks/hooks.json · 13 lines

The source is not reproduced here

Licensed AGPL-3.0

The repository is licensed AGPL-3.0, which this catalogue does not treat as permission to reproduce the file. Read it at the source.

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. yesterday First seen · 13 lines scan C 222ccddf0d8f

Subscribe to this mod's changes

SessionStart is a hook published in the GitHub repository TwoWells/Catenary (8 stars, last pushed 26d ago), licensed AGPL-3.0. Its token cost is not measured: a hook is shell that never enters the context. A static security scan graded it C with 2 findings (downloads and executes remote code, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.