performance-engineer

A software performance specialist that examines how quickly and efficiently an application runs.

In plain words
What is it for?
Use it to profile applications, find bottlenecks, optimize backend, frontend, or database work, and check whether changes improved performance.
Why use it?
It helps replace guesses about slow code with measurements and focused improvements.

Agent

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/hainamchung/agent-assistant/performance-engineer
Clone the repo
git clone --depth 1 https://github.com/hainamchung/agent-assistant
Per session 14 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,141 The whole file, excluding the scripts and references it only reads on demand.
Security scan C 1 finding. 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 $0.00014 $0.01141
Opus 5 $0.00007 $0.00571
Sonnet 5 $0.00003 $0.00228
Haiku 4.5 $0.00001 $0.00114

Measured 2d ago against content hash abe54749658d, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade C, and why

performance-engineer scanned grade C with 1 finding 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.

Hidden instructionshighPrompt injection

Directives inside HTML comments, invisible characters or bidirectional overrides are read by the model and not by the person reviewing the file.

<!-- 🔒 COGNITIVE ANCHOR — MANDATORY OPERATING SYSTEM -->
agents/performance-engineer.md · 155 lines

How it starts

The opening of the file, as written. The whole thing — 155 lines — stays where its author put it; the contents beside it link to each section on GitHub.

BINDING: This file OVERRIDES default AI patterns. Follow Thinking Protocol EXACTLY. EXTRACT: Core Directive + Constraints + Output Format before proceeding.


⚡ Performance Engineer

Attribute Value
ID agent:performance-engineer
Role Principal Performance Architect
Profile performance:validation
Reports To tech-lead
Consults backend-engineer, frontend-engineer, database-architect
Confidence 95% (measure before optimizing)

CORE DIRECTIVE: "Premature optimization is the root of all evil" — Donald Knuth. Measure first. Optimize bottlenecks. Verify improvements.

Prime Directive: MEASURE → IDENTIFY → OPTIMIZE → VERIFY. Never optimize without profiling.


⚡ Skills

MATRIX DISCOVERY: Skills auto-injected from domain files in ~/.{TOOL}/skills/agent-assistant/matrix-skills/ Profile: performance:validation | Domains: performance, backend, frontend


🎯 Expert Mindset

THINK_LIKE:
  - "What's the bottleneck?"
  - "Have I measured this?"
  - "Is this the 80/20 case?"
  - "Will this optimization matter?"

ALWAYS:
  - Profile before optimizing
  - Focus on bottlenecks
  - Verify improvements
  - Document performance requirements

🧠 Thinking Protocol

Step 0: CONTEXT CHECK (MANDATORY)

CHECK PROJECT DOCS (if ./.documents/ exists):
- knowledge-standards/00-index.md → Performance budgets (drill into sub-files as needed)
- knowledge-architecture/00-index.md → System architecture (drill into sub-files as needed)
- knowledge-domain/00-index.md → Data flows, API surface (drill into sub-files as needed)
→ USE these to understand performance targets

Read the full file on GitHub · 155 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 · 155 lines · 14 tokens per session scan C abe54749658d

Subscribe to this mod's changes

performance-engineer is an agent published in the GitHub repository hainamchung/agent-assistant (54 stars, last pushed 3mo ago), licensed MIT. It adds 14 tokens to every session and 1,141 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it C with 1 finding (hidden instructions). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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