Project Surface Scan

Purpose / When to Activate

Activate:

• As Stage 1 of the /gaai:bootstrap workflow (before LLM synthesis)
• When the bootstrap orchestrator needs quantitative project baseline
• When re-running bootstrap after major structural changes

Produces surface_scan_result — a structured object consumed by Stage 2 LLM synthesis.

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Exclusions (always skip)

node_modules/   .git/   dist/   build/   .next/   .nuxt/
out/            .cache/ coverage/ .turbo/ .wrangler/
__pycache__/    .venv/  venv/   target/ vendor/
*.lock          *.log

Additionally: respect any .gitignore present at the project root. Use the Glob tool with explicit exclusion patterns — do NOT use find or rg (permission-error-safe tools only).

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Process

Step 1 — Timed scan start

Record wall-clock start time before any file operations:

scan_start_ms = Date.now()   # conceptual — note the start time

Log: [project-surface-scan] scan started at {ISO timestamp}

Step 2 — File tree walk

Use the Glob tool with pattern **/* from the project root.

Apply exclusion filter: skip any path segment matching the exclusion list above.

Build per-directory count map:

dir_counts: { "<directory>": <file_count> }

Aggregate at depth-1 and depth-2 only (to avoid noise from deep nesting). If a directory has > 500 files, record "<dir>": ">500" and do not recurse further.

Permission errors: if the Glob tool returns an error for a path, log the error as a warning and continue. Never abort on permission errors. Partial scan is acceptable.

Step 3 — Extension frequency map

From the file list obtained in Step 2, build:

ext_counts: { ".ts": 42, ".md": 18, ".json": 12, ... }

Exclude paths without extension (binaries, lock files, dotfiles) from this map.

Step 4 — Language detection

Map extensions to languages using this heuristic table:

Extension(s)	Language
.ts, .tsx	TypeScript
.js, .mjs, .cjs, .jsx	JavaScript
.py	Python
.go	Go
.rs	Rust
.java	Java
.kt, .kts	Kotlin
.rb	Ruby
.php	PHP
.cs	C#
.cpp, .cc, .cxx, .c, .h	C/C++
.swift	Swift
.sh, .bash, .zsh	Shell
.sql	SQL
.yaml, .yml	YAML
.json	JSON
.md, .mdx	Markdown
.html, .htm	HTML
.css, .scss, .sass, .less	CSS/SCSS
.toml	TOML
.graphql, .gql	GraphQL

Aggregate by language (sum all matching extensions). Produce a ranked list:

languages: [
  { language: "TypeScript", file_count: 42, rank: 1 },
  { language: "Markdown",   file_count: 18, rank: 2 },
  ...
]

Include only languages with ≥ 2 files. Unknown extensions are grouped as "Other".

Step 5 — LOC estimation

For the top 5 languages by file count (up to 20 files each, sampled uniformly if more), use the Read tool to count lines. Sum line counts across all sampled files.

Project total LOC = (sampled_lines / sampled_files) × total_files

Permission errors on individual files: log as warning, skip file, do not abort.

Size class determination:

if total_estimated_loc < 10_000:    size_class = "small"
elif total_estimated_loc < 100_000: size_class = "medium"
else:                                size_class = "large"

Step 6 — Observability summary

Record:

scan_duration_ms = Date.now() - scan_start_ms   # conceptual

Log (stdout):

[project-surface-scan] done in {scan_duration_ms}ms
  files: {total_file_count}
  languages: {len(languages)} detected
  estimated LOC: {total_estimated_loc} ({size_class})
  errors: {permission_error_count} permission errors skipped

---

Output Schema (surface_scan_result)

surface_scan_result:
  scanned_at: "2026-04-29T12:00:00Z"       # ISO timestamp
  scan_duration_ms: 1234
  total_file_count: 247
  permission_errors: 0                       # count of skipped paths
  size_class: "medium"                       # small | medium | large
  estimated_loc: 42800
  dir_counts:                                # depth-1 directories
    src: 183
    tests: 41
    docs: 23
  languages:                                 # ranked by file count
    - language: TypeScript
      file_count: 142
      rank: 1
    - language: Markdown
      file_count: 38
      rank: 2
  ext_counts:                                # raw extension map
    .ts: 142
    .md: 38
    .json: 27

---

Quality Checks

• total_file_count > 0 (non-empty scan)
• At least 1 language detected
• scan_duration_ms is recorded (non-zero)
• size_class is one of small | medium | large
• Permission errors logged but did not abort scan

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Non-Goals

This skill must NOT:

• Interpret architecture decisions (use architecture-extract)
• Read file contents beyond LOC sampling
• Write to memory directly (use memory-ingest after Stage 2 synthesis)
• Make recommendations about the codebase

Scans the terrain quantitatively. Does not interpret it.