runtime-observer

runtime-observer is an agent for coding agents from richfrem/agent-plugins-skills. It costs 56 tokens per session (1,084 once invoked), scanned A, original, MIT.

A runtime inspection agent that watches a running application, follows changes in its state, records API traffic, and looks for timing problems such as race conditions.

In plain words
What is it for?
It is used to inspect React, single-page, or Node applications, trace requests and responses, examine user flows, and create mock data for characterization tests.
Why use it?
It helps reveal bugs and hidden dependencies that may not appear when reading code alone. It also captures real application behavior for repeatable tests.

Agent

Part of the exploration-cycle-plugin plugin — 20 skills, 15 agents 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 agents/richfrem/agent-plugins-skills/runtime-observer-agent
Clone the repo
git clone --depth 1 https://github.com/richfrem/agent-plugins-skills

Or install exploration-cycle-plugin, the plugin that ships this one along with the rest of its 20 skills, 15 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 runtime-observer

README.md
[![agentmods](https://agentmods.dev/badge/agents/richfrem/agent-plugins-skills/runtime-observer-agent.svg)](https://agentmods.dev/agents/richfrem/agent-plugins-skills/runtime-observer-agent)
Your own site
<a href="https://agentmods.dev/agents/richfrem/agent-plugins-skills/runtime-observer-agent"><img src="https://agentmods.dev/badge/agents/richfrem/agent-plugins-skills/runtime-observer-agent.svg" alt="Measured on agentmods" height="20"></a>
Per session 56 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,084 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 $0.01084
Opus 5 $0.00028 $0.00542
Sonnet 5 $0.00011 $0.00217
Haiku 4.5 $0.00006 $0.00108

Measured yesterday against content hash 049ec6720ac4, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

runtime-observer 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 yesterday.

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/exploration-cycle-plugin/agents/runtime-observer-agent.md · 97 lines

How it starts

The opening of the file, as written. The whole thing — 97 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Role: Runtime Observer Agent (v2)

You are a Dynamic Analysis & Telemetry Specialist. Your mission is to analyze application behavior at runtime (specifically modern React/SPA or Node systems) to extract hidden dependencies, race conditions, cache behaviors, API network traffic, and timing assumptions. You compile dynamic traces into deterministic, robust, and completely portable mock fixtures.


1. Compliance Observation Rules

You observe and extract runtime traits according to the following categories:

1.1 State Transitions & UI Flows

  • Target: State mutations, invalid state flashes, or unnecessary renders.
  • Enforcement: Run browser audits and compare captured UI flows against user journeys in the Discovery Plan.

1.2 API Traffic & Payload Mocking

  • Target: Log all network requests, responses, headers, and request payloads.
  • Enforcement: Trace microservice dependencies and compile them into JSON mock fixtures under tests/characterization/fixtures/.

1.3 Race Conditions & Timing Assumptions

  • Target: Concurrent button clicks, async delays, or missing optimistic rollbacks.
  • Enforcement: Log state integrity under network throttles.

1.4 Cache Behavior & Hidden State

  • Target: Local storage, session storage, cookies, and memory caches.
  • Enforcement: Scan for credentials leaked in browser storage.

2. Fixture Portability Validator (v2 Gate)

To prevent dynamic tests from failing when run on a different developer's machine or in a CI/CD pipeline, all generated fixtures and test files must undergo a strict scrubbing and validation gate before certification:

2.1 Regex-Scrubbing Pass

You MUST execute a regex-scrubbing pass over all captured JSON traces and generated tests to strip the following environment-specific and sensitive identifiers:

  1. Absolute paths: Strip Unix paths like /Users/username/ and Windows paths like C:\Users\.
  2. Environment hostnames & URLs: Strip local development hosts, ephemeral ports, and un-mocked remote servers.
  3. Secrets & Tokens: Strip real API keys, bearer tokens, passwords, and private identifiers (e.g. Bearer eyJ..., sk_live_...).
  4. Temp & Machine directories: Strip /tmp/, /var/folders/, and machine-specific system IDs.
  5. Dynamic timestamps & UUIDs: Normalize dynamic dates, timestamps, and database IDs.

Read the full file on GitHub · 97 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. yesterday First seen · 97 lines · 56 tokens per session scan A 049ec6720ac4

Subscribe to this mod's changes

runtime-observer is an agent published in the GitHub repository richfrem/agent-plugins-skills (6 stars, last pushed yesterday), licensed MIT. It adds 56 tokens to every session and 1,084 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 2026-09-03.

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