/nw-hotspot

name: nw-hotspot
description: "Git change frequency hotspot analysis — find the most-changed files in your codebase"
user-invocable: true
argument-hint: '[--top=N] [--since=6m] [--json] [--rank report.md] [--detail file]'

NW-HOTSPOT: Code Crime Scene Hotspot Lens

**Wave**: CROSS_WAVE **Execution**: Inline (no agent — Claude executes git commands directly) **Inspiration**: Adam Tornhill's "Your Code as a Crime Scene"

Overview

Analyze git change frequency to identify the most-changed files in a codebase. Pure git churn — no complexity metrics. Use as a **pre-filter** to scope analysis or a **post-filter** to prioritize existing findings.

How It Works

Run `git log --name-only` over the configured time period, count commits per file, rank by frequency.

Modes

1. Analyze (default)

Show the most-changed files in the repo. Output is inline only — no files persisted.

/nw-hotspot
/nw-hotspot --top=20
/nw-hotspot --since=12m

**Steps:** 1. Run: `git log --since={since} --format=format: --name-only | sort | uniq -c | sort -rn` 2. Exclude deleted files (verify each file still exists with `test -f`) 3. For each file, get last changed date: `git log -1 --format="%ar" -- {file}` 4. Display ranked table (top N):

 Rank │ Commits │ Last Changed │ File
──────┼─────────┼──────────────┼─────────────────────────
    1 │      87 │ 2 days ago   │ src/services/payment.ts
    2 │      64 │ 1 week ago   │ src/api/controllers/user.ts
    3 │      51 │ 3 days ago   │ src/models/order.ts

5. Show summary: total files changed in period, time period, top N shown

**Defaults:** `--top`: 15, `--since`: 6 months

2. Rank (post-filter)

Overlay churn data on an existing analysis report to prioritize findings.

/nw-hotspot --rank code-smell-detector-report.md

**Steps:** 1. Run the same git churn analysis 2. Read the specified report file 3. Extract file paths mentioned in the report 4. Annotate each file with its commit count 5. Re-sort findings by churn (highest first). Findings without extractable file paths go at the bottom. 6. Show noise reduction: "X of Y findings are in low-churn files (< 20 commits)"

3. Detail (deep-dive)

Deep-dive into a single file's change history.

/nw-hotspot --detail src/services/payment.ts

**Steps:** 1. Monthly commit breakdown over the period 2. Top contributors to the file 3. Co-change coupling: top 5 files that frequently change alongside this one 4. Last 10 commit messages for context

4. JSON export (pre-filter composition)

/nw-hotspot --top=10 --json

Output: `[{"path": "src/services/payment.ts", "commits": 87, "last_changed": "2 days ago"}, ...]`

Parameters

| Flag | Default | Description | |------|---------|-------------| | `--top` | 15 | Number of files to show | | `--since` | 6m | Time period (e.g., 3m, 12m, 2024-01-01) | | `--json` | false | Output as JSON array | | `--rank` | - | Path to existing report to re-rank by churn | | `--detail` | - | Path to single file for deep-dive |

Edge Cases

• **No commits in period**: Display "No commits found since {date}" rather than an empty table
• **File renames**: Counted as separate files (no `--follow`; keeps it simple and fast)
• **Empty repo / not a git repo**: Display error and exit

Usage from Other Skills

Pre-filter (scope downstream analysis)

Run `/nw-hotspot --top=10 --json` first, then pass the file list to:

• **code-smell-detector**: "Analyze only these files: {hotspot list}"
• **cognitive-load-analyzer**: "Focus analysis on these files: {hotspot list}"
• **refactoring-expert**: "Prioritize recommendations for these files"

Post-filter (rank existing findings)

Run `/nw-hotspot --rank {report.md}` after any analysis to prioritize by churn.

In nWave workflows

• Before `/nw-refactor` — identify which files to refactor first
• Before `/nw-review` — focus review effort on high-churn areas
• Before `/nw-root-why` — check if the problematic area is a known hotspot

Next Wave

**Usage Context**: Inline utility, composable with any analysis skill **Handoff To**: Invoking context (no sequential handoff)

Examples

Example 1: Quick scan of a legacy codebase

/nw-hotspot

Example 2: Scope a code smell analysis to hotspots

/nw-hotspot --top=10 --json

Example 3: Prioritize an existing refactoring report

/nw-hotspot --rank code-refactoring-report.md

Example 4: Investigate a specific troubled file

/nw-hotspot --detail src/services/payment.ts

Expected Outputs

No persistent files. Output is displayed inline. JSON mode outputs a JSON array for composition with other tools.