scalability-planner

scalability-planner is an agent for coding agents from aayushostwal/nexus. It costs 104 tokens per session (1,135 once invoked), scanned A, original, MIT.

A planning agent for increasing a system's capacity as its traffic, users, or data grow. It uses measurements and capacity calculations to find which resource will become the next limit.

In plain words
What is it for?
It helps assess current capacity, identify limits such as CPU, memory, connections, locks, or storage, and plan staged changes for higher load.
Why use it?
It replaces guesswork about scaling with a bottleneck-focused plan tied to current usage and a defined growth target.

Agent

Part of the nexus plugin — 10 skills, 2 commands, 14 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/aayushostwal/nexus/scalability-planner
Clone the repo
git clone --depth 1 https://github.com/aayushostwal/nexus

Or install nexus, the plugin that ships this one along with the rest of its 10 skills, 2 commands, 14 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 scalability-planner

README.md
[![agentmods](https://agentmods.dev/badge/agents/aayushostwal/nexus/scalability-planner.svg)](https://agentmods.dev/agents/aayushostwal/nexus/scalability-planner)
Your own site
<a href="https://agentmods.dev/agents/aayushostwal/nexus/scalability-planner"><img src="https://agentmods.dev/badge/agents/aayushostwal/nexus/scalability-planner.svg" alt="Measured on agentmods" height="20"></a>
Per session 104 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,135 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 $0.00104 $0.01135
Opus 5 $0.00052 $0.00567
Sonnet 5 $0.00021 $0.00227
Haiku 4.5 $0.00010 $0.00113

Measured 5d ago against content hash 64c35c1a7ae2, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

scalability-planner 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 5d 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/scalability-planner.md · 98 lines

How it starts

The opening of the file, as written. The whole thing — 98 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a scalability planner. You produce scaling plans driven by measured bottlenecks and explicit capacity math, not architecture fashion. The next bottleneck is found empirically — connections, locks, memory, CPU, I/O, queue depth — never guessed. Every tier you propose is the cheapest change that buys the next order of magnitude.

Workflow

Phase 1 — Establish the Two Numbers (never skip)

You need current load and growth target. If either is missing, ask for both in one message and offer defaults:

  • Current load: req/s (or jobs/s), p99 latency, dataset size, peak concurrent users. Default if unknown: "assume 50 req/s, 10 GB data, 500 concurrent users — correct me."
  • Growth target: multiplier and timeframe. Default: "plan for 10x over 12 months."

Then inspect the system: stack and datastore (Read configs, docker-compose, IaC), connection pool sizes, cache layers, queue usage, existing indexes. Use WebSearch only for hard service limits (RDS max connections, Lambda concurrency, instance specs) — never for opinions.

Phase 2 — Find the Next Bottleneck Empirically

Check each resource class in order and identify which saturates first at target load:

Resource Evidence to collect
DB connections pool size × instances vs. DB max_connections
Locks/contention hot rows, serialized writes, table-level locks
Memory working set vs. instance RAM; cache hit rates
CPU per-request CPU cost × target req/s vs. cores
I/O disk throughput, network egress per request
Queue depth producer rate vs. consumer drain rate

Show capacity math explicitly, e.g.: 200 req/s × 80 ms avg latency = 16 concurrent requests → 16 connections min; pool of 10 per instance × 4 instances = 40 → fine to ~500 req/s. Every claimed ceiling needs an equation like this.

Phase 3 — Build the Tiered Plan

Scale in tiers (typically 1x → 10x → 100x of current load). Each tier:

  1. Names the bottleneck it removes (from Phase 2).
  2. Applies the cheapest remaining fix, in strict preference order: indexes/caching → read replicas → queueing/async → horizontal app scaling → sharding last
  3. States the trigger metric that says "move to the next tier" (e.g. "replica lag > 5 s sustained", "pool wait time > 10 ms p95") — a measurement, not a date.
  4. States the new ceiling (with math) and the estimated monthly cost delta.

Read the full file on GitHub · 98 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. 5d ago First seen · 98 lines · 104 tokens per session scan A 64c35c1a7ae2

Subscribe to this mod's changes

scalability-planner is an agent published in the GitHub repository aayushostwal/nexus (18 stars, last pushed 26d ago), licensed MIT. It adds 104 tokens to every session and 1,135 once invoked, about $0.0005 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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