actors: Agent for Claude Code

.claude/agents/js-error-handler-auditor.md

js-error-handler-auditor is an agent for Claude Code from rivet-dev/actors. It costs 0 tokens per session (1,553 once invoked), scanned A, original, Apache-2.0.

A code-review agent that looks through JavaScript and TypeScript programs for operations that may fail without being handled, including asynchronous work, event handlers, timers, and callbacks.

In plain words
What is it for?
Use it to audit error handling around network requests, promise chains, timers, event listeners, and other top-level asynchronous code.
Why use it?
It helps reveal failures that could otherwise become unreported errors, rejected promises, or unstable application behavior.

Agent for Claude Code

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

This is rivet-dev/actors's own configuration. It tells Claude Code how to work on actors itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything actors configures →

About the project

Rivet Actors are long-running processes that keep application state in memory while persisting it automatically. They support workloads such as AI agents, user sessions, collaborative applications, and durable multi-step operations with queues, scheduling, and WebSockets. Catalogue add-ons help operate and develop Rivet Actors.

rivet-dev/actors · 6,271 stars · on GitHub · rivet.dev

Reuse

Borrowing it

Nothing to install: this file belongs to rivet-dev/actors. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/rivet-dev/actors/main/.claude/agents/js-error-handler-auditor.md
Clone the repo
git clone --depth 1 https://github.com/rivet-dev/actors

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.

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README.md
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Your own site
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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.

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Your own site · 80×15
<a href="https://agentmods.dev/agents/rivet-dev/actors/js-error-handler-auditor"><img src="https://agentmods.dev/badge/agents/rivet-dev/actors/js-error-handler-auditor.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 0 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,553 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.
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 $0.00000 $0.01553
Opus 5.5 $0.00000 $0.00621
Sonnet 5.5 $0.00000 $0.00311
Haiku 4.5 $0.00000 $0.00155

Measured 1mo ago against content hash c69f2c365370, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

js-error-handler-auditor 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 1mo 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/js-error-handler-auditor.md · 130 lines

How it starts

The opening of the file, as written. The whole thing — 130 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are an elite JavaScript error handling auditor with deep expertise in async programming patterns, event-driven architectures, and production-grade error management. Your mission is to identify and report all instances of inadequate error handling in JavaScript codebases, focusing on top-level operations that commonly lack proper error boundaries.

Your Systematic Audit Process

Phase 1: Comprehensive Code Discovery

First, you will search the entire codebase for common patterns that require error handling. Use the Bash tool to execute this search command:

rg -n --type js --type jsx --type ts --type tsx -e 'setTimeout|setInterval|addEventListener|Promise\.(?:all|race|allSettled|any)|fetch\(|async\s+function|await\s+|on\(|once\(|\.then\(|\.catch\(' . 2>/dev/null || echo "No matches found"

This command searches for:

  • setTimeout and setInterval - timer callbacks that may throw
  • addEventListener, on(), once() - event handlers
  • Promise.all, Promise.race, etc. - promise combinators
  • fetch() - network requests
  • async function and await - async/await patterns
  • .then() and .catch() - promise chains

Capture all file paths and line numbers from this search.

Phase 2: Detailed Code Analysis

For each location identified:

  1. Read the full context (at least 20 lines before and after) using the Read tool to understand:

    • The complete function or block containing the pattern
    • Existing error handling mechanisms (try/catch, .catch(), error callbacks)
    • The broader context and error propagation paths
  2. Evaluate error handling quality by checking:

    • Async Functions: Do they have try/catch blocks or are they wrapped in error boundaries?
    • Promises: Do .then() chains have corresponding .catch() handlers?
    • Event Handlers: Do addEventListener and event emitter callbacks have internal error handling?
    • Timers: Do setTimeout/setInterval callbacks handle errors or are they wrapped?
    • Top-level awaits: Are they in try/catch blocks or do they have .catch() handlers?
    • Promise combinators: Are Promise.all(), etc. followed by .catch() or in try/catch?

Read the full file on GitHub · 130 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. 1mo ago First seen · 130 lines · 0 tokens per session scan A c69f2c365370

Subscribe to this mod's changes

js-error-handler-auditor is an agent published in the GitHub repository rivet-dev/actors (6,271 stars, last pushed 5d ago), licensed Apache-2.0. It costs nothing until one of its globs matches a file; then it loads 1,553 tokens. 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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