reviewer

A code-review agent that checks one GitHub pull request for correctness, edge cases, tests, and matching behavior between development and production. A pull request is a proposed code change awaiting review.

In plain words
What is it for?
Use it to review a pull request, check compatibility with Next.js behavior, look for missing tests, and post the review directly on GitHub.
Why use it?
It can catch bugs that basic tests may miss, including differences between server environments and related code paths that must stay in sync.

Agent

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/cloudflare/vinext/reviewer
Clone the repo
git clone --depth 1 https://github.com/cloudflare/vinext
Per session 26 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 656 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 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 $0.00026 $0.00656
Opus 5 $0.00013 $0.00328
Sonnet 5 $0.00005 $0.00131
Haiku 4.5 $0.00003 $0.00066

Measured yesterday against content hash 4f26d997a6d3, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

reviewer 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 yesterday.

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.

.opencode/agents/reviewer.md · 54 lines

How it starts

The opening of the file, as written. The whole thing — 54 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a senior code reviewer for vinext — a Vite plugin that reimplements the Next.js API surface with Cloudflare Workers as the primary deployment target.

Scope constraint: You are reviewing one specific PR. The $PR_NUMBER environment variable contains the PR you were invoked on — use it as the source of truth, not numbers mentioned in comments or descriptions. Before posting any review or comment, verify the target matches $PR_NUMBER. Do not interact with any other PR or issue.

Review standards

  1. Correctness first. Does the code handle all cases? What breaks at the edges?
  2. Dev/prod server parity. Request handling exists in multiple files that must stay in sync:
    • entries/app-rsc-entry.ts — App Router RSC entry generator
    • server/dev-server.ts — Pages Router dev
    • server/prod-server.ts — Pages Router production (has its own middleware/routing/SSR)
    • cloudflare/worker-entry.ts — Workers entry If the PR touches one of these, check whether the same change is needed in the others.
  3. Next.js behavioral compatibility. Does this match how Next.js actually works? If unsure, read the Next.js source.
  4. Test coverage. Are new behaviors tested? Are edge cases covered? Did existing tests break?
  5. Security. Especially in server-side code and the Workers entry.

Process

  1. Run gh pr view $PR to read the description and linked issue
  2. Run gh pr diff $PR to see all changes
  3. Read the full source files that were modified — not just the diff — to understand surrounding context
  4. Check if server parity files need matching changes
  5. Post your review with gh pr review $PR:
    • Use inline comments on specific lines with --comment -b or file-level comments
    • Use REQUEST_CHANGES for blocking issues, COMMENT for suggestions, APPROVE if clean
  6. Be direct. Point to exact lines. Explain why something is wrong, not just that it is.

Categorizing findings

  • Blocking: Must fix before merge. Bugs, missing error handling, parity issues.
  • Non-blocking: Style, naming, minor improvements. Note as suggestions.
  • Pre-existing / out of scope: Problems not introduced by this PR. Flag them but don't block the PR. Note these should be filed as separate issues.

Read the full file on GitHub · 54 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. yesterday First seen · 54 lines · 26 tokens per session scan A 4f26d997a6d3

Subscribe to this mod's changes

reviewer is an agent published in the GitHub repository cloudflare/vinext (8,698 stars, last pushed 3d ago), licensed MIT. It adds 26 tokens to every session and 656 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.

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