daemon-debug

A troubleshooting guide for background processes, automatic startup, proxy connections, ports, and recovery problems. A daemon is a program that runs in the background, while a proxy forwards requests to another process.

In plain words
What is it for?
Use it when a daemon will not start, a proxy is missing or unhealthy, a port is occupied, or automatic recovery is not working.
Why use it?
It provides an ordered way to find whether the process, configuration, URL detection, port, or proxy is causing the failure.

Skill for Claude CodeCodex

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/standardbeagle/agnt/daemon-debug
Any agent
npx skills add standardbeagle/agnt --skill daemon-debug
Clone the repo
git clone --depth 1 https://github.com/standardbeagle/agnt

Made for: Claude Code, Codex.

Per session 24 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,356 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 $0.00024 $0.01356
Opus 5 $0.00012 $0.00678
Sonnet 5 $0.00005 $0.00271
Haiku 4.5 $0.00002 $0.00136

Measured 2d ago against content hash 748b68c5ed0c, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

daemon-debug 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 2d 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/skills/daemon-debug/SKILL.md · 138 lines

How it starts

The opening of the file, as written. The whole thing — 138 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Daemon Debugging

Use this skill when diagnosing why processes aren't starting, proxies are missing, ports are occupied, or the autostart flow isn't working.

Diagnostic Checklist

Work through these in order. Each step either finds the problem or rules out a category.

1. Verify Daemon State

# Is the daemon running?
agnt daemon status

# What processes does the daemon know about?
printf 'PROC LIST\n;;\n' | socat - UNIX-CONNECT:/tmp/devtool-mcp-$(id -u).sock

# What proxies exist?
printf 'PROXY LIST\n;;\n' | socat - UNIX-CONNECT:/tmp/devtool-mcp-$(id -u).sock

Decode base64 JSON responses. Check:

  • Are expected processes listed?
  • What state are they in? (running / failed / etc.)
  • Do running processes have urls populated?
  • Are any warnings present (rogue processes)?

2. Check Config

# Read the project config
cat /path/to/project/.agnt.kdl

For each proxy with script set:

  • Does the linked script exist in scripts {}?
  • Does the script have url-matchers? Do they match actual output format?
  • Does the proxy have fallback-port? (safety net if URL detection fails)

3. Verify URL Detection

URL detection is the #1 failure point for script-linked proxies.

Common URL matcher mismatches:

Dev server Actual output Correct matcher
dotnet Now listening on: http://localhost:6111 "Now listening on: {url}"
Vite Local: http://localhost:5173/ "Local:\\s+{url}"
Next.js - Local: http://localhost:3000 "Local:\\s+{url}"
Flask Running on http://127.0.0.1:5000 "Running on {url}"

How to test: Check process output for the URL line, then verify the matcher pattern (with {url} removed) matches as a regex substring.

4. Check Port Bindings

# Linux: what's listening on expected ports?
ss -tlnp | grep -E ':(6111|6112|3000|5173)\b'

# Compare against daemon's tracked processes
# If port is occupied by a PID the daemon doesn't own → rogue process

Read the full file on GitHub · 138 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. 2d ago First seen · 138 lines · 24 tokens per session scan A 748b68c5ed0c

Subscribe to this mod's changes

daemon-debug is a skill published in the GitHub repository standardbeagle/agnt (19 stars, last pushed 3d ago), licensed Apache-2.0. It adds 24 tokens to every session and 1,356 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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