buildkite-plugin-security

buildkite-plugin-security is a skill for Claude Code, Codex from hasithaishere/buildkite-developer-toolkit. It costs 133 tokens per session (1,193 once invoked), scanned C, original, MIT.

A security review workflow for Buildkite plugins, which are extensions that run as part of Buildkite's software delivery pipelines. It checks plugins written in Bash, Docker, or Go for common security problems.

In plain words
What is it for?
It scans for command and argument injection, secret leakage, unsafe eval, missing quoting, and supply-chain risks, with additional checks when tools such as ShellCheck or Gosec are installed.
Why use it?
It helps find issues that could let untrusted pipeline settings run commands, expose secrets, or compromise a build agent.

Skill for Claude CodeCodex

Part of the buildkite-developer-toolkit plugin — 7 skills shipped together

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 skills/hasithaishere/buildkite-developer-toolkit/buildkite-plugin-security
Any agent
npx skills add hasithaishere/buildkite-developer-toolkit --skill buildkite-plugin-security
Clone the repo
git clone --depth 1 https://github.com/hasithaishere/buildkite-developer-toolkit

Made for: Claude Code, Codex.

Or install buildkite-developer-toolkit, the plugin that ships this one along with the rest of its 7 skills.

Per session 133 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,193 The whole file, excluding the scripts and references it only reads on demand.
Security scan C 3 findings. Scan, not verified.
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.

ModelPer sessionOnce invoked
Fable 5 $0.00133 $0.01193
Opus 5 $0.00067 $0.00596
Sonnet 5 $0.00027 $0.00239
Haiku 4.5 $0.00013 $0.00119

Measured 3d ago against content hash 913f43147b4a, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade C, and why

buildkite-plugin-security scanned grade C with 3 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.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/scan-plugin.sh), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

Downloads and executes remote codemediumSupply chain

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

tag, an unverified download, or a `curl | bash` is RCE on their agents.

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

Recursive force deletemediumDestructive command

rm -rf with a variable or a broad path is one typo away from removing the wrong tree.

| Filesystem | predictable temp paths (not `mktemp`), `rm -rf` on unguarded vars |

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.

quoting, supply-chain (unpinned images/deps, unverified downloads, curl|bash),
skills/buildkite-plugin-security/SKILL.md · 93 lines

How it starts

The opening of the file, as written. The whole thing — 93 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Buildkite plugin security review

You are a security engineer auditing a Buildkite plugin. Plugin hooks run on the agent with the agent's privileges, and their configuration comes from pipeline YAML that may be influenced by less-trusted contributors — so a plugin bug is often an agent-level RCE or secret-exfiltration bug. Be thorough and skeptical.

Threat model (assume the worst)

  • Plugin config is attacker-influenceable. BUILDKITE_PLUGIN_* values come from pipeline YAML; on a repo that accepts PRs, a contributor may control them. Treat every config value as untrusted input.
  • Hooks run with agent privileges — often able to reach secrets, the Docker daemon, cloud metadata, and other jobs' state on the same agent.
  • The plugin is a supply-chain dependency for everyone who uses it: a moved tag, an unverified download, or a curl | bash is RCE on their agents.

How to run the scan

Run the bundled scanner against the plugin repo:

bash "${CLAUDE_SKILL_DIR}/scripts/scan-plugin.sh" <plugin-dir>

It performs static checks (below) and, when those tools are installed, also runs shellcheck, hadolint (Dockerfile), gitleaks (committed secrets), gosec + govulncheck (Go), and trivy (deps/secrets/IaC). It prints findings as SEVERITY [ID] message -> file:line and exits non-zero if any HIGH finding is present (pass --no-fail to report-only). Wire it into the plugin's own CI so regressions are caught.

Then manually review anything the scanner can't see (see the catalog) and confirm/triage each finding — static patterns over-report; judge each in context.

What the scanner checks (categories)

Category Examples
Injection / RCE eval of config, curl|bash, building shell strings from BUILDKITE_PLUGIN_*
Secret handling password on the command line (use --password-stdin), echo/set -x of secrets, secrets committed
Supply chain unpinned base image / :latest, ADD from URL, downloads without checksum, vulnerable Go deps
Privilege --privileged, Docker socket mount, never dropping root
Transport TLS verification disabled (curl -k)
Filesystem predictable temp paths (not mktemp), rm -rf on unguarded vars
Robustness hooks missing set -euo pipefail / shebang

Read the full file on GitHub · 93 lines

Files

What ships with it

2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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 · 93 lines · 133 tokens per session scan C 913f43147b4a

Subscribe to this mod's changes

buildkite-plugin-security is a skill published in the GitHub repository hasithaishere/buildkite-developer-toolkit (2 stars, last pushed 1mo ago), licensed MIT. It adds 133 tokens to every session and 1,193 once invoked, about $0.0007 per session on Opus 5. A static security scan graded it C with 3 findings (downloads and executes remote code, recursive force delete, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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