eng-observability

eng-observability is a skill for Claude Code from tjboudreaux/cc-plugin-engineering-excellence. It costs 31 tokens per session (347 once invoked), scanned A, original, MIT.

A software-engineering guide for adding logs, measurements, and traces that show what a system is doing and why it failed.

In plain words
What is it for?
Use it when changing mobile, web, or web3 systems that need structured diagnostics, error signals, correlation IDs, or on-chain events.
Why use it?
It makes production problems easier to investigate without attaching a debugger, while keeping useful user and environment context.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the engineering-excellence plugin — 13 skills, 4 agents shipped together

Good fit Use it when changing mobile, web, or web3 systems that need structured diagnostics, error signals, correlation IDs, or on-chain events.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/tjboudreaux/cc-plugin-engineering-excellence/eng-observability
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 tjboudreaux/cc-plugin-engineering-excellence --skill eng-observability
Clone the repo
git clone --depth 1 https://github.com/tjboudreaux/cc-plugin-engineering-excellence

Made for: Claude Code.

Or install engineering-excellence, the plugin that ships this one along with the rest of its 13 skills, 4 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 eng-observability

README.md
[![agentmods](https://agentmods.dev/badge/skills/tjboudreaux/cc-plugin-engineering-excellence/eng-observability/github.svg)](https://agentmods.dev/skills/tjboudreaux/cc-plugin-engineering-excellence/eng-observability)
Your own site
<a href="https://agentmods.dev/skills/tjboudreaux/cc-plugin-engineering-excellence/eng-observability"><img src="https://agentmods.dev/badge/skills/tjboudreaux/cc-plugin-engineering-excellence/eng-observability/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 eng-observability

Your own site · 80×15
<a href="https://agentmods.dev/skills/tjboudreaux/cc-plugin-engineering-excellence/eng-observability"><img src="https://agentmods.dev/badge/skills/tjboudreaux/cc-plugin-engineering-excellence/eng-observability.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 31 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 347 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 $0.00031 $0.00347
Opus 5 $0.00015 $0.00173
Sonnet 5 $0.00006 $0.00069
Haiku 4.5 $0.00003 $0.00035

Measured 9d ago against content hash 311fd3b16991, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

eng-observability 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 9d 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.

skills/eng-observability/SKILL.md · 30 lines

What it actually says

Observability and Debugging Discipline

Intent

  • Make it trivial to answer “what is happening” and “why” without attaching a debugger in production.
  • Ensure logs, metrics, events, and traces capture user intent, environment, and failure context while protecting sensitive data.

Guiding Principles

  1. Prefer structured logs + correlation IDs over ad-hoc strings.
  2. Emit signals at every boundary (client, API, worker, contract invocation).
  3. Include context (user/session/network/chain) necessary to reproduce issues.
  4. Keep signal cost reasonable—throttle chatty paths, sample intelligently.
  5. Build fast local debugging loops (trace replay, state inspectors, dev wallets).

Workflow

  1. Identify critical paths affected and define success/error signals per path.
  2. Add/extend tracing spans or log blocks with consistent field names.
  3. Validate observability locally by simulating successes, errors, and timeouts; ensure signals reach the sink (console, APM, analytics, chain explorer).
  4. Document dashboards, queries, or CLI commands useful for post-deploy verification.
  5. For on-chain logic, emit events with canonical schema so downstream indexers can consume them.

Verification

  • Run the code with verbose logging/tracing enabled; inspect outputs for clarity and privacy.
  • Confirm metrics/counters appear where expected (APM, telemetry pipeline, analytics, chain explorer).
  • Dry-run incident response: can you locate a test failure or simulated outage using only emitted signals? If not, iterate.
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. 9d ago First seen · 30 lines · 31 tokens per session scan A 311fd3b16991

Subscribe to this mod's changes

eng-observability is a skill published in the GitHub repository tjboudreaux/cc-plugin-engineering-excellence (4 stars, last pushed 7mo ago), licensed MIT. It adds 31 tokens to every session and 347 once invoked, about $0.0002 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 2026-08-31.

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