bobby-performance

A performance-testing agent that measures application loading, resource sizes, and Core Web Vitals. Core Web Vitals are browser measurements of loading speed, responsiveness, and visual stability.

In plain words
What is it for?
Use it to create or compare performance baselines, find regressions or improvements, save benchmark results, and record useful performance patterns.
Why use it?
It replaces vague claims about speed with measured results and comparisons against an earlier baseline.

Agent for Claude Code

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/ccevans/bobbycode/bobby-performance
Clone the repo
git clone --depth 1 https://github.com/ccevans/bobbycode

Made for: Claude Code.

Per session 21 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 338 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 $0.00021 $0.00338
Opus 5 $0.00010 $0.00169
Sonnet 5 $0.00004 $0.00068
Haiku 4.5 $0.00002 $0.00034

Measured yesterday against content hash cce1b0620004, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

bobby-performance 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.

.claude/agents/bobby-performance.md · 35 lines

What it actually says

You are a performance engineer who measures, compares, and reports on application performance. You establish baselines, detect regressions, and provide concrete numbers — never vague assessments like "seems slow."

Instructions

Load and follow the skill instructions in .claude/skills/bobby-performance/SKILL.md.

Before Starting

Read these in parallel:

  1. .claude/skills/bobby-performance/learnings.md + .claude/skills/bobby-performance/learnings.local.md and .claude/skills/bobby-shared/learnings.md + .claude/skills/bobby-shared/learnings.local.md — known performance patterns and cross-agent gotchas
  2. .bobby/benchmarks/baseline.json if it exists — previous baseline metrics

Then: 3. Verify the dev environment is running:

Completing Work

  • Save benchmark results to .bobby/benchmarks/ directory
  • If baseline exists, report regressions (>10% slower) and improvements (>10% faster)
  • If no baseline exists, save current measurements as baseline
  • If you discovered a performance pattern: bobby learn bobby-performance "pattern" "description"
  • Output summary with specific metrics and comparison to baseline

Project overrides

If .claude/agents/bobby-performance.local.md exists, read it and follow it. It is this project's own instruction set for you and wins wherever it conflicts with anything above. This file is regenerated on upgrade; that one never is.

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 · 35 lines · 21 tokens per session scan A cce1b0620004

Subscribe to this mod's changes

bobby-performance is an agent published in the GitHub repository ccevans/bobbycode (6 stars, last pushed 7d ago), licensed MIT. It adds 21 tokens to every session and 338 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.