demo-4-review-swarm

demo-4-review-swarm is a skill for Claude Code, Codex from decodingai-magazine/building-a-coding-agent-from-scratch-course. It costs 50 tokens per session (751 once invoked), scanned A, original, Apache-2.0.

A demonstration of parallel code review using three read-only reviewers, each examining a different part of a codebase. The reviewers inspect permissions, sandbox execution, or session context, then combine their findings.

In plain words
What is it for?
Use it to inspect the three decode modules, identify correctness and error-handling risks, rank findings by severity, assign health scores, and write one verdict file.
Why use it?
It shows how to review several modules at the same time while preventing the reviewers from changing files.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions subagents.

Good fit Use it to inspect the three decode modules, identify correctness and error-handling risks, rank findings by severity, assign health scores, and write one verdict file.

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Install with agentmods
npx agentmods add skills/decodingai-magazine/building-a-coding-agent-from-scratch-course/demo-4-review-swarm
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 decodingai-magazine/building-a-coding-agent-from-scratch-course --skill demo-4-review-swarm
Clone the repo
git clone --depth 1 https://github.com/decodingai-magazine/building-a-coding-agent-from-scratch-course

Made for: Claude Code, Codex.

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 demo-4-review-swarm

README.md
[![agentmods](https://agentmods.dev/badge/skills/decodingai-magazine/building-a-coding-agent-from-scratch-course/demo-4-review-swarm/github.svg)](https://agentmods.dev/skills/decodingai-magazine/building-a-coding-agent-from-scratch-course/demo-4-review-swarm)
Your own site
<a href="https://agentmods.dev/skills/decodingai-magazine/building-a-coding-agent-from-scratch-course/demo-4-review-swarm"><img src="https://agentmods.dev/badge/skills/decodingai-magazine/building-a-coding-agent-from-scratch-course/demo-4-review-swarm/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 demo-4-review-swarm

Your own site · 80×15
<a href="https://agentmods.dev/skills/decodingai-magazine/building-a-coding-agent-from-scratch-course/demo-4-review-swarm"><img src="https://agentmods.dev/badge/skills/decodingai-magazine/building-a-coding-agent-from-scratch-course/demo-4-review-swarm.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 50 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 751 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
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 5.1 $0.00050 $0.00751
Opus 5 $0.00025 $0.00376
Sonnet 5 $0.00010 $0.00150
Haiku 4.5 $0.00005 $0.00075

Measured 11d ago against content hash 44c1d832b0d3, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

demo-4-review-swarm 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 11d 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.

.decode/skills/demo-4-review-swarm/SKILL.md · 59 lines

How it starts

The opening of the file, as written. The whole thing — 59 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Run a parallel code-review swarm over decode's own source: three read-only Explore subagents review three modules at once, and you fold their reports into a single severity-ranked verdict with a health scorecard.

This is a showcase of the agent tool's native parallel fan-out (ADR-0013): N agent(...) calls in one response run concurrently, each an Explore subagent whose toolset is read-only by construction (read / glob / grep / lsp — no write, edit, or bash). Nothing the subagents do mutates the repo.

Fan out — three subagents in ONE response

Spawn all three Explore subagents in a single model turn (so they run in parallel, not one after the other), one per module:

  • Subagent A → src/decode/permissions/ — the allow/ask/deny gate, rules, and permission modes.
  • Subagent B → src/decode/sandbox/ — the executor seam, docker/modal backends, workspace, and hand-back.
  • Subagent C → src/decode/context/ — compaction and the JSONL session log.

Give each subagent the same brief: read every file in its module and report, as a read-only reviewer, on correctness, clarity, error handling, and any risky edges. Ask each one to return:

  1. A short prose summary of what the module does and how its files fit together.
  2. A text-based diagram of the module's structure — a Mermaid flowchart showing the files and how they call each other.
  3. A flat list of findings, each tagged with a severity: Critical, Major, or Minor — each naming the file:line it refers to.
  4. A health score from 1 to 10 with a one-sentence justification.

Merge — one severity-ranked verdict

When all three reports come back, fold them into ONE verdict — do NOT paste the three reports verbatim:

  • A health scorecard up top: one row per module with its score /10 and the one-line justification.
  • A single findings table across all three modules, ranked by severity: every Critical first, then every Major, then every Minor — each row naming the module and the file:line it refers to.
  • The three modules' Mermaid diagrams, one per module, each under its own heading.
  • A two-or-three-line closing judgement: is the reviewed code healthy, and what is the single most important thing to fix first?

Read the full file on GitHub · 59 lines

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. 11d ago First seen · 59 lines · 50 tokens per session scan A 44c1d832b0d3

Subscribe to this mod's changes

demo-4-review-swarm is a skill published in the GitHub repository decodingai-magazine/building-a-coding-agent-from-scratch-course (383 stars, last pushed yesterday), licensed Apache-2.0. It adds 50 tokens to every session and 751 once invoked, about $0.0003 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.