observability

Guidance for observability, the practice of understanding running software through metrics, logs, and traces.

In plain words
What is it for?
Use it when designing monitoring, collecting application data, building dashboards, setting alerts, or reviewing production incidents.
Why use it?
It helps teams find failures, slow requests, and resource problems, then monitor whether services meet reliability targets.

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/saitarrun/devforge-ai/observability
Any agent
npx skills add saitarrun/Devforge-ai --skill observability
Clone the repo
git clone --depth 1 https://github.com/saitarrun/Devforge-ai

Made for: Claude Code, Codex.

Per session 44 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 725 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 $0.00044 $0.00725
Opus 5 $0.00022 $0.00362
Sonnet 5 $0.00009 $0.00145
Haiku 4.5 $0.00004 $0.00072

Measured 2d ago against content hash 5958c25002dd, 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 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.

skills/observability/SKILL.md · 113 lines

How it starts

The opening of the file, as written. The whole thing — 113 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Skill: Observability (Metrics, Logs, Traces)

Three pillars: Metrics (what), Logs (why), Traces (how). Use all three.

Metrics (Time-Series Data)

Key metrics:

  • Request latency (p50, p95, p99)
  • Error rate (%)
  • Throughput (req/s)
  • Resource (CPU, memory, disk)

Collection: Prometheus, StatsD, CloudWatch

api_latency_seconds{service="auth", endpoint="/login"} = 0.042
error_rate{service="api"} = 0.001
db_connections{pool="default"} = 42

Logging (Structured)

Format: JSON for parsing

{
  "timestamp": "2024-01-15T10:30:45Z",
  "level": "ERROR",
  "service": "user-service",
  "message": "Failed to create user",
  "error": "database_error",
  "user_id": "user-123",
  "duration_ms": 150
}

Sampling: Log 100% errors, 1% normal (reduce volume)

Distributed Tracing

Trace request end-to-end:

Request: POST /api/users
├─ Auth span (5ms)
├─ Validate span (2ms)
├─ DB insert span (45ms)
│  ├─ Connection span (1ms)
│  └─ Query span (44ms)
└─ Cache update span (3ms)
Total: 55ms

Tools: Jaeger, Zipkin, Datadog

Dashboards (SLO-Focused)

What to display:

  • SLO % (100% target, 99% actual)
  • Error budget consumed (%)
  • Latency (p95, p99)
  • Errors per minute
  • Active requests
  • Alert status

Tools: Grafana, CloudWatch, Datadog

Alerting

Good alert (actionable):

Alert: DB connection pool > 80%
Severity: CRITICAL
Action: Increase pool size or check for connection leaks
Runbook: https://wiki.example.com/alerts/db-pool-high

Bad alert (not actionable):

Alert: Disk usage > 50%
(What should I do?)

SLO-Driven Alerting

SLO: 99.9% uptime
Error budget: 8.64 hours/month

Alert: If burn rate > 1% → 30 days to fail budget
Alert: If burn rate > 10% → 3 days to fail budget

Monitoring Checklist

  • Latency metrics (p50, p95, p99)
  • Error rate (%)
  • Saturation (CPU, memory, disk)
  • Dependencies (external API uptime)
  • Custom business metrics
  • SLO dashboard
  • Alert rules (with runbooks)

Read the full file on GitHub · 113 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 · 113 lines · 44 tokens per session scan A 5958c25002dd

Subscribe to this mod's changes

observability is a skill published in the GitHub repository saitarrun/Devforge-ai (5 stars, last pushed 19d ago), licensed Apache-2.0. It adds 44 tokens to every session and 725 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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