cf-optimize

name	cf-optimize
description	Structured optimization workflow — baseline, analyze, optimize, measure, compare. Auto-invoke this skill when the conversation involves performance optimization, speed improvements, or the user mentions something is slow — e.g. "this is slow", "make it faster", "optimize", "performance", "bottleneck", "too many queries", "high latency", "memory leak", "reduce load time", "speed up", "takes too long", "timeout", "O(n²)", "N+1". Do NOT auto-invoke for minor refactors or style changes that are not performance-related.
user-invocable	true
argument-hint	[target to optimize]
created	2026-02-20T00:00:00.000Z
updated	2026-07-04T00:00:00.000Z
model	opus

/cf-optimize

CLI Requirement: OPTIONAL — Uses the memory MCP from coding-friend-cli for fast indexed search and storage. Without the CLI: falls back to grep over docs/memory/ and direct file writes. Full functionality preserved, slower memory recall. See CLI requirements.

Optimize: $ARGUMENTS

Purpose

Structured workflow for optimizing existing features, algorithms, or performance-critical code. Ensures every optimization is measured before and after so you know it actually helped.

Workflow

Step 0: Custom Guide

Custom guide — auto-loaded below (if the raw command shows instead of its output, run it yourself):

bash "${CLAUDE_PLUGIN_ROOT}/lib/load-custom-guide.sh" cf-optimize

If output is not empty, integrate returned sections: ## Before → before first step, ## Rules → apply throughout, ## After → after final step.

Step 1: Detect Available Tools

Run quick availability checks for profiling/benchmarking tools. Store the result for use in later steps.

# Node.js / JavaScript
command -v clinic >/dev/null 2>&1 && echo "TOOL:clinic"
command -v 0x >/dev/null 2>&1 && echo "TOOL:0x"
npx lighthouse --version >/dev/null 2>&1 && echo "TOOL:lighthouse"

# General
command -v hyperfine >/dev/null 2>&1 && echo "TOOL:hyperfine"
command -v perf >/dev/null 2>&1 && echo "TOOL:perf"

# Web / Bundle
command -v webpack-bundle-analyzer >/dev/null 2>&1 && echo "TOOL:webpack-bundle-analyzer"

If no tools are found, note this and proceed in AI-only mode — all profiling will be done via code instrumentation and manual timing. Results in AI-only mode are estimates; flag this clearly in the final report.

Step 2: Understand the Target

1. Read $ARGUMENTS to identify what to optimize
2. If the target is vague, ask the user to clarify what "better" means:
   • Faster execution time?
   • Lower memory usage?
   • Fewer API calls / network requests?
   • Smaller bundle size?
   • Better algorithmic complexity?

Step 3: Gather Context (conditional — based on target complexity)

Assess whether the optimization target is simple (single file/function, clear scope) or complex (cross-module, unclear bottleneck location, system-level):

• Simple target (e.g., "optimize this function"): Search memory only (if memory_search tool is available). Call memory_search with: { "query": "<optimization target keywords — e.g. performance, latency, bottleneck, caching>", "limit": 5 }. Then read the relevant source files directly.

• Complex target (e.g., "API is slow", "reduce page load time", cross-module performance): Launch the cf-explorer agent to map the system context. Use the Agent tool with subagent_type: "coding-friend:cf-explorer". Pass:

  Explore the codebase to understand the performance context for: [optimization target]

  Questions to answer:

  1. What is the call chain / data flow for this operation?
  2. What modules, services, or layers are involved?
  3. Are there existing benchmarks, caching layers, or performance-related code?
  4. What dependencies (DB queries, API calls, I/O) are in the critical path?

  Note: cf-explorer already checks memory internally — do NOT call memory_search separately when using cf-explorer.

Memory and explorer results are hints — always verify against actual code and measurements.

Step 4: Baseline Measurement

1. Identify or create a benchmark/measurement. Prefer detected tools from Step 1:
   • hyperfine → hyperfine --warmup 3 '<command>' (automatic 3-run avg + stats)
   • clinic → clinic doctor -- node <script> (Node.js flamegraph + I/O analysis)
   • 0x → 0x <script> (flamegraph for hot path detection)
   • lighthouse → lighthouse <url> --output json --quiet (web performance audit)
   • perf → perf stat <command> (CPU counters on Linux)
   • No tools → create a simple benchmark (manual timing, console.time(), memory snapshots)
2. Run the baseline measurement 3 times to get stable numbers (hyperfine does this automatically)
3. Record the results clearly:
   • Metric name, value, unit
   • Environment details (if relevant)
   • Which tool was used (or "AI-only" if no tools)
4. Save baseline numbers — you will need them for comparison in Step 8

Step 5: Analyze Bottlenecks

1. Profile the code path (add timing, use profiler if available)
2. Identify the actual bottleneck — do NOT guess:
   • Where is time spent?
   • What allocations are excessive?
   • What operations are redundant?
3. Rank bottlenecks by impact (fix the biggest one first)

Step 6: Plan the Optimization

1. For the top bottleneck, propose 1-2 optimization approaches
2. For each approach, state:
   • What changes: specific files and functions
   • Expected improvement: rough estimate
   • Risk: what could break
3. Present the plan to the user and wait for confirmation before proceeding
4. Do NOT optimize multiple things at once — one change at a time

Step 7: Implement (via cf-implementer agent)

Dispatch the cf-implementer agent to implement the optimization test-first. Use the Agent tool with subagent_type: "coding-friend:cf-implementer".

Prompt template:

Implement the following optimization:

Optimization: [approach confirmed in Step 6] Target: [specific files and functions] Bottleneck: [from Step 5 analysis] Baseline: [measurements from Step 4] Existing tests: [test file paths] Test framework: [framework and conventions]

Requirements:

1. If tests exist for the target code, verify they pass before changing anything
2. If no tests exist, write tests first that verify current behavior
3. Implement the optimization — one change at a time
4. Run all tests — no regressions allowed
5. Report: what was changed, test results, any concerns

Review the cf-implementer's report. If tests failed or the agent reported concerns, address them before proceeding. Then load the cf-verification skill and run the full checklist before measuring.

Capturing out-of-scope side-effects

While optimizing, if you notice a problem unrelated to the performance target that is non-trivial (fixing it inline would muddy the before/after measurement or expand scope), do NOT fix it now. Record it for later, then continue:

bash "${CLAUDE_PLUGIN_ROOT}/lib/capture-later.sh" \
  --name "<short title>" --description "<what & where — enough to act on cold>" \
  --source cf-optimize [--slug <task slug, if one exists>] [--problem "<the optimization target>"]

This writes <docsDir>/later/YYYY-MM-DD-<name>.md with frontmatter (slug, problem, conversation_id). This is an in-repo audit trail, independent of the spawn_task tool.

Step 8: Measure After

1. Run the exact same benchmark from Step 4 (same tool, same parameters)
2. Run it 3 times for stable numbers
3. Record the results

Step 9: Compare and Report

1. Present a before/after comparison:

Metric	Before	After	Change
metric	value	value	% or absolute change

2. If improvement is < 5%, note that it may be within noise — consider if the added complexity is worth it
3. If performance regressed, revert and try a different approach (go back to Step 6)
4. Summarize what was changed and why it helped
5. If running in AI-only mode (no profiling tools), add a disclaimer: "Measurements are code-instrumented estimates — install hyperfine or clinic for precise benchmarks."

Step 10: Auto-Review

Automatically invoke /cf-review — use the Skill tool with skill name coding-friend:cf-review. Do NOT ask the user first, just run it.

If review.withCodex: true is set in the config, cf-review automatically runs a Codex second-opinion review alongside Claude's and merges both — no flag needed here (cf-review reads the config itself).

Completion Protocol

• DONE — Optimization verified with measurements. Show: before/after comparison table, % improvement, files changed.
• DONE_WITH_CONCERNS — Optimization applied but improvement is marginal (< 5%) or has trade-offs. Show: numbers + trade-off analysis.
• BLOCKED — Cannot optimize. Show: why (can't measure, no clear bottleneck, would require architectural change). Suggest next action.

Rules

• ALWAYS measure before AND after — no "it should be faster" claims
• One optimization at a time — never batch multiple changes
• Tests must pass throughout — run existing tests after every change
• Get user confirmation before implementing (Step 6)
• If you cannot measure it, ask the user how to measure it before proceeding
• Revert if the optimization makes things worse or breaks tests
• Prefer real profiling tools over AI estimation when available

Tool Integration

Tool	Domain	Install	Used For
hyperfine	General	brew install hyperfine / cargo install hyperfine	Precise CLI benchmarking with warmup and statistical analysis
clinic	Node.js	npm i -g clinic	Flamegraphs, I/O profiling, bubbleprof
0x	Node.js	npm i -g 0x	Lightweight flamegraph generation
lighthouse	Web	npm i -g lighthouse	Web performance audit (LCP, FID, CLS)
perf	Linux	System package	CPU counters, cache misses, syscall profiling
webpack-bundle-analyzer	JS bundles	npm i -D webpack-bundle-analyzer	Bundle size visualization

When no tools are detected, cf-optimize falls back to AI-only mode: manual console.time(), process.memoryUsage(), and code-level instrumentation. Results are clearly marked as estimates.