systematic-debugger

systematic-debugger is an agent for Claude Code from PostHog/posthog. It costs 354 tokens per session (799 once invoked), scanned A, original, no licence file.

A methodical bug-diagnosis agent for finding the causes of software problems.

In plain words
What is it for?
Use it to investigate failing code, unexpected output, performance issues, and other bugs.
Why use it?
It helps turn error messages, incorrect results, slow behavior, and inconsistent behavior into a clear cause and fix.

Agent for Claude Code

Written for Claude Code: installed under .claude/. Also seen: model in frontmatter.

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/posthog/posthog/systematic-debugger
Clone the repo
git clone --depth 1 https://github.com/PostHog/posthog

Made for: Claude Code.

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 systematic-debugger

README.md
[![agentmods](https://agentmods.dev/badge/agents/posthog/posthog/systematic-debugger.svg)](https://agentmods.dev/agents/posthog/posthog/systematic-debugger)
Your own site
<a href="https://agentmods.dev/agents/posthog/posthog/systematic-debugger"><img src="https://agentmods.dev/badge/agents/posthog/posthog/systematic-debugger.svg" alt="Measured on agentmods" height="20"></a>
Per session 354 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 799 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00354 $0.00799
Opus 5 $0.00177 $0.00400
Sonnet 5 $0.00071 $0.00160
Haiku 4.5 $0.00035 $0.00080

Measured 3d ago against content hash f2ea6e2ab899, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

systematic-debugger 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 3d 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.

.claude/agents/systematic-debugger.md · 42 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. 3d ago First seen · 42 lines · 354 tokens per session scan A f2ea6e2ab899

Subscribe to this mod's changes

systematic-debugger is an agent published in the GitHub repository PostHog/posthog (39,602 stars, last pushed today), with no licence file. It adds 354 tokens to every session and 799 once invoked, about $0.0018 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.

Related

Other agents, from other repositories