observability

observability is a skill for Claude Code, Codex from xobotyi/cc-foundry. It costs 56 tokens per session (5,037 once invoked), scanned A, original, MIT.

A guide to observability, the practice of understanding a running system from its external signals. It explains logs for events, metrics for measured trends, and traces for following work across services.

In plain words
What is it for?
Adding or reviewing structured logs, metrics, distributed traces, alerts, and connections between signals during debugging or system design.
Why use it?
It helps choose the right signal for a question instead of treating all monitoring data alike. That makes failures, performance problems, and system behavior easier to investigate.

Skill for Claude CodeCodex

Part of the backend plugin — 4 skills shipped together

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/xobotyi/cc-foundry/observability
Any agent
npx skills add xobotyi/cc-foundry --skill observability
Clone the repo
git clone --depth 1 https://github.com/xobotyi/cc-foundry

Made for: Claude Code, Codex.

Or install backend, the plugin that ships this one along with the rest of its 4 skills.

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 observability

README.md
[![agentmods](https://agentmods.dev/badge/skills/xobotyi/cc-foundry/observability.svg)](https://agentmods.dev/skills/xobotyi/cc-foundry/observability)
Your own site
<a href="https://agentmods.dev/skills/xobotyi/cc-foundry/observability"><img src="https://agentmods.dev/badge/skills/xobotyi/cc-foundry/observability.svg" alt="Measured on agentmods" height="20"></a>
Per session 56 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 5,037 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 $0.00056 $0.05037
Opus 5 $0.00028 $0.02518
Sonnet 5 $0.00011 $0.01007
Haiku 4.5 $0.00006 $0.00504

Measured 4d ago against content hash 3d1afe33ecc0, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

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 4d 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/backend/skills/observability/SKILL.md · 530 lines

How it starts

The opening of the file, as written. The whole thing — 530 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Observability

If you cannot ask arbitrary questions about your system's behavior from the outside, your system is not observable — it is merely monitored.


The Three Pillars

Logs — What Happened

Logs are timestamped, discrete event records. They capture what happened at a specific moment: an error thrown, a user action, a configuration loaded, a connection refused.

Use logs when you need:

  • Rich diagnostic context for a specific event
  • Debugging information with full error details and stack traces
  • Audit trails of who did what and when
  • Record of discrete state transitions

Logs are poor at:

  • Showing aggregate system health (use metrics)
  • Tracing request flow across services (use traces)
  • High-frequency numeric trends (too expensive at volume)

Metrics — How Is It Doing

Metrics are numeric measurements aggregated over time. They capture how the system is performing as quantitative time series: request rates, error percentages, latencies, queue depths, resource utilization.

Use metrics when you need:

  • Real-time health signals and alerting
  • Trend analysis over hours, days, weeks
  • Capacity planning and saturation monitoring
  • Pre-aggregated data that scales cheaply regardless of traffic

Metrics are poor at:

  • Explaining why something is broken (use logs)
  • Showing the path of a single request (use traces)
  • Storing per-event detail (cardinality explosion)

Traces — How Did It Flow

Traces record the causal chain of operations that make up a single request as it propagates through distributed components. A trace is a tree of spans, where each span represents one unit of work (an HTTP call, a database query, a queue publish).

Use traces when you need:

  • End-to-end latency breakdown across services
  • Dependency mapping and bottleneck identification
  • Understanding the path a failing request took
  • Correlating work across process and network boundaries

Traces are poor at:

  • Aggregate health monitoring (use metrics)
  • Detailed per-event diagnostics on a single node (use logs)
  • Cheap, long-term trend storage (traces are expensive at 100% sampling)

Read the full file on GitHub · 530 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 4d ago First seen · 530 lines · 56 tokens per session scan A 3d1afe33ecc0

Subscribe to this mod's changes

observability is a skill published in the GitHub repository xobotyi/cc-foundry (20 stars, last pushed yesterday), licensed MIT. It adds 56 tokens to every session and 5,037 once invoked, about $0.0003 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.

Related

Other skills, from other repositories

systematic-debugging

Use when encountering any bug, test failure, or unexpected behavior, before proposing fixes.

obra/superpowers · 21 tokens

brainstorming

You MUST use this before any creative work - creating features, building components, adding functionality, or modifying behavior. Explores user intent, requirements and design before implementation.

obra/superpowers · 37 tokens

auto-perf-optimize

Run agent-driven VS Code performance or memory investigations. Use when asked to launch Code OSS, automate a VS Code scenario, run the Chat memory smoke runner, capture renderer heap snapshots, take workflow screenshots, compare run summaries, or drive a repeatable scenario before heap-snapshot analysis.

microsoft/vscode · 62 tokens

chat-perf

Run chat perf benchmarks and memory leak checks against the local dev build or any published VS Code version. Use when investigating chat rendering regressions, validating perf-sensitive changes to chat UI, or checking for memory leaks in the chat response pipeline.

microsoft/vscode · 51 tokens

chat-pet-sprite-creation

Use when creating or changing VS Code chat pet sprite art, sprite sheets, state animations, eye treatments, Stable/Insiders variants, or pet transitions under src/vs/workbench/contrib/chat/browser/widget/media/chatPet.

microsoft/vscode · 53 tokens

cpu-profile-analysis

Analyze V8/Chrome CPU profiles (.cpuprofile) and DevTools trace files (Trace-.json). Use when: profiling performance, investigating slow functions, comparing code paths, finding bottlenecks, analyzing timeToRequest, understanding call trees from sampling profiler data, analyzing layout/paint/rendering, investigating…

microsoft/vscode · 71 tokens