d3k

d3k is a skill for Claude Code, Codex from varandrew/moor. It costs 12 tokens per session (1,252 once invoked), scanned A, original, Apache-2.0.

A developer tool for collecting browser and server logs, inspecting errors, crawling application URLs, and controlling a browser session.

In plain words
What is it for?
Use it to view logs, investigate build or application errors, discover pages, click and fill browser elements, take screenshots, or start a fresh browser profile.
Why use it?
It brings related browser and server information into one place, making it easier to trace failures and reproduce what happened before an error.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: installed under .agents/ (shared by several agents); mentions 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 skills/varandrew/moor/d3k
Any agent
npx skills add varandrew/moor --skill d3k
Clone the repo
git clone --depth 1 https://github.com/varandrew/moor

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 d3k

README.md
[![agentmods](https://agentmods.dev/badge/skills/varandrew/moor/d3k.svg)](https://agentmods.dev/skills/varandrew/moor/d3k)
Your own site
<a href="https://agentmods.dev/skills/varandrew/moor/d3k"><img src="https://agentmods.dev/badge/skills/varandrew/moor/d3k.svg" alt="Measured on agentmods" height="20"></a>
Per session 12 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,252 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. 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 5.1 $0.00012 $0.01252
Opus 5 $0.00006 $0.00626
Sonnet 5 $0.00002 $0.00250
Haiku 4.5 $0.00001 $0.00125

Measured 6d ago against content hash 4a434b081cce, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

d3k scanned grade A with 1 finding 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 6d 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.

Makes network callslowCapability

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

curl -I http://127.0.0.1:3000
.agents/skills/d3k/SKILL.md · 155 lines

How it starts

The opening of the file, as written. The whole thing — 155 lines — stays where its author put it; the contents beside it link to each section on GitHub.

d3k Commands

d3k captures browser and server logs in a unified log file. Use these commands:

Viewing Errors and Logs

d3k errors              # Show recent errors (browser + server combined)
d3k errors --context    # Show errors + user actions that preceded them
d3k errors -n 20        # Show last 20 errors

d3k logs                # Show recent logs (browser + server combined)
d3k logs --type browser # Browser logs only
d3k logs --type server  # Server logs only

Other Commands

d3k fix                 # Deep analysis of application errors
d3k fix --focus build   # Focus on build errors

d3k crawl               # Discover app URLs
d3k crawl --depth all   # Exhaustive crawl

Browser Interaction

d3k agent-browser auto-connects to the active session's browser via CDP:

d3k agent-browser open http://localhost:3000/page
d3k agent-browser snapshot -i    # Get element refs (@e1, @e2)
d3k agent-browser click @e2
d3k agent-browser fill @e3 "text"
d3k agent-browser screenshot /tmp/shot.png

To target a different browser, run d3k agent-browser connect <port> first.

Codex Fresh Browser/Profile Startup

Use this workflow when the user asks Codex to start d3k with a fresh browser/profile.

  1. Close any stale agent-browser daemon before launching with --profile. Otherwise agent-browser will reuse the existing daemon and print --profile ignored.

    d3k agent-browser close --all
    
  2. Start the app through d3k in servers-only mode and keep that command running. In Codex, this is more reliable than asking d3k to launch the browser itself when a fresh profile is required.

    d3k --no-agent --no-skills --servers-only --command "npm run dev -- -H 127.0.0.1 -p 3000" --port 3000 --startup-timeout 90 --no-tui
    

    Adjust the package-manager command and port for the project. Prefer --command over --script when passing framework flags. For npm scripts, put flags after --; otherwise tools like Next.js can interpret the port as a project directory.

Read the full file on GitHub · 155 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. 6d ago First seen · 155 lines · 12 tokens per session scan A 4a434b081cce

Subscribe to this mod's changes

d3k is a skill published in the GitHub repository varandrew/moor (199 stars, last pushed 4d ago), licensed Apache-2.0. It adds 12 tokens to every session and 1,252 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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