logging-patterns

logging-patterns is a skill for Claude Code from Jartan-LLC/grimoire. It costs 16 tokens per session (456 once invoked), scanned A, original, MIT.

A set of conventions for writing application logs, which are records of what a program is doing. It covers logger setup, message formatting, severity levels, and where output should go.

In plain words
What is it for?
Use it when adding logs to Python modules, command-line programs, filters, pipelines, or services that send logs to monitoring systems.
Why use it?
It prevents inconsistent or hard-to-search logs and makes it clearer which messages are routine, recoverable, or serious.

Skill for Claude Code

Written for Claude Code: user-invocable in frontmatter.

Part of the praxis plugin — 16 skills, 7 agents shipped together

Good fit Use it when adding logs to Python modules, command-line programs, filters, pipelines, or services that send logs to monitoring systems.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/jartan-llc/grimoire/logging-patterns
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 Jartan-LLC/grimoire --skill logging-patterns
Clone the repo
git clone --depth 1 https://github.com/Jartan-LLC/grimoire

Made for: Claude Code.

Or install praxis, the plugin that ships this one along with the rest of its 16 skills, 7 agents.

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 logging-patterns

README.md
[![agentmods](https://agentmods.dev/badge/skills/jartan-llc/grimoire/logging-patterns/github.svg)](https://agentmods.dev/skills/jartan-llc/grimoire/logging-patterns)
Your own site
<a href="https://agentmods.dev/skills/jartan-llc/grimoire/logging-patterns"><img src="https://agentmods.dev/badge/skills/jartan-llc/grimoire/logging-patterns/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 logging-patterns

Your own site · 80×15
<a href="https://agentmods.dev/skills/jartan-llc/grimoire/logging-patterns"><img src="https://agentmods.dev/badge/skills/jartan-llc/grimoire/logging-patterns.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 16 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 456 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 $0.00016 $0.00456
Opus 5.5 $0.00006 $0.00182
Sonnet 5.5 $0.00003 $0.00091
Haiku 4.5 $0.00002 $0.00046

Measured 1mo ago against content hash 4c130f7d7418, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

logging-patterns 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.

plugins/praxis/skills/logging-patterns/SKILL.md · 52 lines

What it actually says

Logging Conventions

Setup

One logger per module, at module level:

import logging

logger = logging.getLogger(__name__)

Formatting

Use %s-style formatting arguments, not f-strings -- the message template is preserved for structured aggregator queries:

logger.info("Cleaned up %d expired sessions", count)  # yes
logger.exception("SMTP send failed for %s", email)    # yes (in an except handler)
logger.info(f"Cleaned up {count} expired sessions")   # no

%s deferral is stdlib-specific -- structlog uses kwargs, not %s. See pythonica:python-observability.

Level Conventions

Level Use for
DEBUG Cache hit/miss, slow-path internals (opt-in only)
INFO Startup/shutdown, admin bootstrap, cleanup counts, rate limit hits
WARNING Recoverable anomalies, swallowed exceptions, degraded operation
ERROR Unexpected exceptions on operational paths -- use logger.exception(...)
CRITICAL Reserved for unusable state

Output

Log to stderr when stdout carries the program's own output -- the common case: CLIs, filters, pipeline stages (also Python's logging.StreamHandler default). Use stdout only for pure log-shipping services that emit nothing else. One record per line either way. Container runtimes (Docker, k8s) capture both streams, so the choice isolates logs from program output, not runtime visibility -- no file sinks or log rotation in-app.

Support two formats via config:

  • plain -- Readable for local dev
  • json -- Stable single-line object per record for log aggregators (Loki, Datadog, ELK, CloudWatch)

Timestamps in UTC in both formats.

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 · 52 lines · 16 tokens per session scan A 4c130f7d7418

Subscribe to this mod's changes

logging-patterns is a skill published in the GitHub repository Jartan-LLC/grimoire (2 stars, last pushed yesterday), licensed MIT. It adds 16 tokens to every session and 456 once invoked, about $0.0001 per session on Opus 5.5. 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 2026-08-31.