chain-builder

An agent for finding ways to combine separate security bugs into a larger attack. It looks for chains such as an access-control flaw followed by an authentication bypass.

In plain words
What is it for?
It is for reviewing a bug and identifying possible follow-on weaknesses, such as SSRF reaching cloud metadata or XSS leading to account takeover.
Why use it?
A group of linked bugs can have a more serious combined impact than each bug alone.

Agent for Codex

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/guib1/red-team-docker/chain-builder
Clone the repo
git clone --depth 1 https://github.com/guib1/red-team-docker

Made for: Codex.

Per session 96 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,081 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 2 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 $0.00096 $0.01081
Opus 5 $0.00048 $0.00541
Sonnet 5 $0.00019 $0.00216
Haiku 4.5 $0.00010 $0.00108

Measured 2d ago against content hash 6b2ab42258a9, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade B, and why

chain-builder scanned grade B 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 2d 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.

Cloud metadata endpointmediumServer-side request forgery

One request to 169.254.169.254 can return temporary IAM credentials.

| SSRF DNS callback | 169.254.169.254 cloud metadata | Critical |

Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.

Makes network callslowCapability

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

- Use `curl` for HTTP requests (researcher provides auth headers)
pentest-lab/.agents/skills/bug-bounty/agents/chain-builder.md · 90 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. 2d ago First seen · 90 lines · 96 tokens per session scan B 6b2ab42258a9

Subscribe to this mod's changes

chain-builder is an agent published in the GitHub repository guib1/red-team-docker (1 stars, last pushed 4mo ago), with no licence file. It adds 96 tokens to every session and 1,081 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it B with 2 findings (cloud metadata endpoint, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.