observability-fundamentals

observability-fundamentals is a skill for Claude Code from honeycombio/agent-skill. It costs 145 tokens per session (1,497 once invoked), scanned A, original, MIT.

A guide to the basic ideas behind observability, the practice of understanding what an application is doing from the data it produces. It explains events, metrics, logs, request traces, and the information attached to them.

In plain words
What is it for?
Use it to learn why instrumentation matters, distinguish events from metrics and logs, and understand concepts such as wide events, high-cardinality fields, and the observability analysis loop.
Why use it?
It helps choose useful application data and understand how that data supports answering unexpected debugging questions, instead of relying only on predefined dashboards.

Skill for Claude Code

Written for Claude Code: ${CLAUDE_PLUGIN_ROOT} variable.

Runs only inside its plugin — its command needs a path that Claude Code sets for a plugin’s own hooks and for nothing else. Install the plugin, not this.

Part of the honeycomb plugin — 11 skills, 1 command, 2 agents, 2 hooks shipped together

Good fit Use it to learn why instrumentation matters, distinguish events from metrics and logs, and understand concepts such as wide events, high-cardinality fields, and the observability analysis loop.

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Install

Getting it into your agent

This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.

Claude Code
/plugin marketplace add honeycombio/agent-skill
Claude Code
/plugin install honeycomb

Made for: Claude Code.

Or install honeycomb, the plugin that ships this one along with the rest of its 11 skills, 1 command, 2 agents, 2 hooks.

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-fundamentals

README.md
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Your own site
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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 observability-fundamentals

Your own site · 80×15
<a href="https://agentmods.dev/skills/honeycombio/agent-skill/observability-fundamentals"><img src="https://agentmods.dev/badge/skills/honeycombio/agent-skill/observability-fundamentals.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 145 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,497 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 $0.00145 $0.01497
Opus 5 $0.00072 $0.00749
Sonnet 5 $0.00029 $0.00299
Haiku 4.5 $0.00015 $0.00150

Measured 9d ago against content hash b5e42f75d37f, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

observability-fundamentals 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.

honeycomb/skills/observability-fundamentals/SKILL.md · 132 lines

How it starts

The opening of the file, as written. The whole thing — 132 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Observability Fundamentals

First principles behind Honeycomb's approach to observability. Use this to ground recommendations and answer conceptual questions — for SDK setup and tool-specific guidance, see the otel-instrumentation and query-patterns skills.

Definitions

Observability: The ability to understand and explain any state your system can get into, no matter how novel or complex — by examining what the system produces, without deploying new code for each new question.

Wide event: A flat key-value record capturing the full context of a unit of work — who made the request, which endpoint, cache hit/miss, build version, duration, error status, and any business context relevant to the operation. In OpenTelemetry, a span is a wide event.

High cardinality: The number of unique values a field can have. user.id with millions of values is high cardinality. http.method with a handful is low cardinality.

High dimensionality: The number of distinct fields on your events. A span with 50 attributes has high dimensionality.

Concept Observability Traditional Monitoring
Questions Arbitrary, unknown ahead of time Pre-defined (dashboards, alerts)
Data shape Decided at query time Decided at instrumentation time
Cardinality High cardinality is valuable High cardinality is expensive
Investigation Explore → narrow → confirm Check dashboard → escalate

Why Wide Events

The shape of the data you collect constrains the questions you can ask later. Metrics pre-aggregate context away at instrumentation time. Wide events preserve context and let you decide the shape of your analysis at query time.

Every attribute on a span is a queryable dimension. Adding user.id, deployment.version, and cache.hit to the same span lets you correlate them in a single query — "slow requests are from tenant X on version 2.3.1 with cache misses." Separate metrics can't do this because each dimension combination creates a new time series.

Read the full file on GitHub · 132 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. 9d ago First seen · 132 lines · 145 tokens per session scan A b5e42f75d37f

Subscribe to this mod's changes

observability-fundamentals is a skill published in the GitHub repository honeycombio/agent-skill (22 stars, last pushed 13d ago), licensed MIT. It adds 145 tokens to every session and 1,497 once invoked, about $0.0007 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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