supabase-extract-jwt

supabase-extract-jwt is a skill for Claude Code from yoanbernabeu/supabase-pentest-skills. It costs 27 tokens per session (2,439 once invoked), scanned A, original, no licence file.

A procedure for finding and decoding Supabase-related JWTs, which are signed data tokens, in client code, cookies, and browser storage.

In plain words
What is it for?
It is for security reviews of Supabase authentication tokens in frontend code and browser data.
Why use it?
It helps reveal tokens that may be exposed where users or browser code can access them.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the supabase-extraction plugin — 5 skills shipped together , and of supabase-complete

Good fit It is for security reviews of Supabase authentication tokens in frontend code and browser data.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/yoanbernabeu/supabase-pentest-skills/supabase-extract-jwt
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 yoanbernabeu/supabase-pentest-skills --skill supabase-extract-jwt
Clone the repo
git clone --depth 1 https://github.com/yoanbernabeu/supabase-pentest-skills

Made for: Claude Code.

Or install supabase-extraction, the plugin that ships this one along with the rest of its 5 skills.

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 supabase-extract-jwt

README.md
[![agentmods](https://agentmods.dev/badge/skills/yoanbernabeu/supabase-pentest-skills/supabase-extract-jwt/github.svg)](https://agentmods.dev/skills/yoanbernabeu/supabase-pentest-skills/supabase-extract-jwt)
Your own site
<a href="https://agentmods.dev/skills/yoanbernabeu/supabase-pentest-skills/supabase-extract-jwt"><img src="https://agentmods.dev/badge/skills/yoanbernabeu/supabase-pentest-skills/supabase-extract-jwt/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.

agentmods 80×15 button for supabase-extract-jwt

Your own site · 80×15
<a href="https://agentmods.dev/skills/yoanbernabeu/supabase-pentest-skills/supabase-extract-jwt"><img src="https://agentmods.dev/badge/skills/yoanbernabeu/supabase-pentest-skills/supabase-extract-jwt.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 27 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,439 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. Third-party audits
  • Socket pass 18 Mar 2026
  • Snyk fail 15 Feb 2026
How audits are shown
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 $0.00027 $0.02439
Opus 5 $0.00014 $0.01220
Sonnet 5 $0.00005 $0.00488
Haiku 4.5 $0.00003 $0.00244

Measured 12d ago against content hash f3270a31d91a, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

supabase-extract-jwt 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 12d 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.

skills/extraction/supabase-extract-jwt/SKILL.md · 361 lines

The source is not reproduced here

A licence we could not identify

The repository carries a LICENSE file, but it is custom or dual enough that GitHub cannot name it and neither can this catalogue. Unknown terms are not permission, so the body is not copied here. Read the licence at the source and decide for yourself.

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. 12d ago First seen · 361 lines · 27 tokens per session scan A f3270a31d91a

Subscribe to this mod's changes

supabase-extract-jwt is a skill published in the GitHub repository yoanbernabeu/supabase-pentest-skills (69 stars, last pushed 7mo ago), with no licence file. It adds 27 tokens to every session and 2,439 once invoked, about $0.0001 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 2026-08-30.