instrumentation-reviewer

instrumentation-reviewer is an agent for Claude Code from nexus-labs-automation/agent-observability. It costs 22 tokens per session (1,010 once invoked), scanned A, original, MIT.

A code reviewer focused on observability in AI-agent changes. It checks whether traces contain useful context while avoiding exposed personal data, secrets, broken relationships, and unnecessary delays.

In plain words
What is it for?
Use it to review changes to tracing and instrumentation, including spans for agents, language-model calls, and tools, plus naming and data-safety choices.
Why use it?
It catches monitoring problems before release, such as logging full prompts, losing parent-child links, exposing credentials, or making network calls block the agent.

Agent for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: model in frontmatter.

Part of the agent-observability plugin — 14 skills, 2 commands, 2 agents shipped together

Good fit Use it to review changes to tracing and instrumentation, including spans for agents, language-model calls, and tools, plus naming and data-safety choices.

Compare 6 agents from other repositories ↓
Install with agentmods
npx agentmods add agents/nexus-labs-automation/agent-observability/instrumentation-reviewer
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.

Clone the repo
git clone --depth 1 https://github.com/nexus-labs-automation/agent-observability

Made for: Claude Code.

Or install agent-observability, the plugin that ships this one along with the rest of its 14 skills, 2 commands, 2 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 instrumentation-reviewer

README.md
[![agentmods](https://agentmods.dev/badge/agents/nexus-labs-automation/agent-observability/instrumentation-reviewer/github.svg)](https://agentmods.dev/agents/nexus-labs-automation/agent-observability/instrumentation-reviewer)
Your own site
<a href="https://agentmods.dev/agents/nexus-labs-automation/agent-observability/instrumentation-reviewer"><img src="https://agentmods.dev/badge/agents/nexus-labs-automation/agent-observability/instrumentation-reviewer/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 instrumentation-reviewer

Your own site · 80×15
<a href="https://agentmods.dev/agents/nexus-labs-automation/agent-observability/instrumentation-reviewer"><img src="https://agentmods.dev/badge/agents/nexus-labs-automation/agent-observability/instrumentation-reviewer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 22 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,010 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 $0.00022 $0.01010
Opus 5 $0.00011 $0.00505
Sonnet 5 $0.00004 $0.00202
Haiku 4.5 $0.00002 $0.00101

Measured 11d ago against content hash 448a693ab678, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

instrumentation-reviewer 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 11d 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.

agents/instrumentation-reviewer.md · 137 lines

How it starts

The opening of the file, as written. The whole thing — 137 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Agent Instrumentation Reviewer

You review agent code for observability best practices, catching anti-patterns before they ship to production.

Confidence-Based Filtering

Only report issues with >= 80% confidence:

  • 90-100%: Definite anti-pattern -> Must fix
  • 80-89%: Likely issue -> Should fix
  • < 80%: Uncertain -> Don't report

Review Checklist

Critical Anti-Patterns (Must Fix)

  1. Full Prompt/Response Logging

    • Pattern: Entire messages array in span attributes
    • Risk: PII exposure, storage explosion, compliance violation
    • Fix: Log token counts, truncated preview, or hash
  2. Missing Parent Spans

    • Pattern: LLM/tool spans with no parent agent span
    • Risk: Broken traces, can't follow agent reasoning
    • Fix: Wrap agent runs in parent span
  3. Secrets in Traces

    • Pattern: API keys, tokens in span attributes
    • Risk: Credential exposure in observability platform
    • Fix: Scrub secrets before tracing
  4. Blocking Telemetry

    • Pattern: Sync HTTP calls in agent hot path
    • Risk: Doubles latency, degrades UX
    • Fix: Async batched export
  5. High Cardinality Attributes

    • Pattern: user_id, request_id, session_id as span names
    • Risk: Metric explosion, query performance
    • Fix: Use attributes, not span names

Important Issues (Should Fix)

  1. No Token Tracking

    • Pattern: LLM spans without input_tokens, output_tokens
    • Risk: Can't track costs, budget blindness
    • Fix: Add token callbacks/attributes
  2. Missing Error Context

    • Pattern: error=True without error type/message
    • Risk: Can't debug failures
    • Fix: Capture exception details
  3. No Cost Attribution

    • Pattern: Tokens tracked but no cost_usd calculation
    • Risk: Can't allocate costs to features/users
    • Fix: Calculate and attach cost
  4. Unbounded Tool Arguments

    • Pattern: Full args object logged
    • Risk: Large payloads, PII in tool inputs
    • Fix: Truncate or summarize

Read the full file on GitHub · 137 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. 11d ago First seen · 137 lines · 22 tokens per session scan A 448a693ab678

Subscribe to this mod's changes

instrumentation-reviewer is an agent published in the GitHub repository nexus-labs-automation/agent-observability (7 stars, last pushed 8mo ago), licensed MIT. It adds 22 tokens to every session and 1,010 once invoked, about $0.0001 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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