update-code-index

A command for scanning a codebase's exported functions, classes, hooks, and components and recording them in CODE_INDEX.md.

In plain words
What is it for?
Building a capability-based code index and checking it before adding new functions, classes, hooks, or components.
Why use it?
The index helps the agent find existing code before creating something new. This reduces duplicate implementations of functions that already exist.

Command 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 commands/brain-bootstrap/claude-code-brain-bootstrap/update-code-index
Clone the repo
git clone --depth 1 https://github.com/brain-bootstrap/claude-code-brain-bootstrap

Made for: Claude Code.

Per session 19 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 689 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 $0.00019 $0.00689
Opus 5 $0.00010 $0.00345
Sonnet 5 $0.00004 $0.00138
Haiku 4.5 $0.00002 $0.00069

Measured 2d ago against content hash af3d2659def3, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

update-code-index 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 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.

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/commands/update-code-index.md · 80 lines

How it starts

The opening of the file, as written. The whole thing — 80 lines — stays where its author put it; the contents beside it link to each section on GitHub.

/update-code-index

Scans source files for all exported functions, classes, hooks, and components. Generates CODE_INDEX.md organized by capability — a "check before write" safety net.

⚠️ Before writing any new function, check CODE_INDEX.md for existing similar ones. Find a match? Use or extend it. Don't create formatDate2() when formatDate() exists.


Instructions

1. Identify source directories

ls -d src/ lib/ app/ core/ 2>/dev/null || true

2. Scan for exports

TypeScript / JavaScript:

grep -rn 'export function\|export const\|export class\|export default' \
  . --include='*.ts' --include='*.tsx' --include='*.js' --include='*.jsx' \
  --exclude-dir=node_modules --exclude-dir=dist --exclude-dir=build --exclude-dir='.next' \
  --exclude-dir=coverage --exclude-dir='.turbo' 2>/dev/null | head -100

Python:

grep -rn '^def \|^async def \|^class ' \
  . --include='*.py' \
  --exclude-dir=__pycache__ --exclude-dir=.venv --exclude-dir=venv --exclude-dir=dist \
  2>/dev/null | head -100

3. Categorize by capability (not by file location)

Group each export by what it does:

Category Match on name or description
Date / Time date, time, format, parse, duration, timestamp
Validation validate, is*, check, verify, sanitize
API clients fetch, get, post, put, delete, request, client
Auth auth, login, logout, session, token, permission
Database db, query, find, create, update, delete, repo
React Hooks use* exports in .tsx files
Components PascalCase exports in .tsx / .jsx
Utilities helper, util, common (catch-all)

4. Write CODE_INDEX.md

Create or overwrite CODE_INDEX.md at the project root:

# Code Index
*Auto-generated by /update-code-index — [TIMESTAMP]*
> Check this before writing new code. Find a match? Use or extend it instead.

## [Category]
- `functionName()` — src/path/to/file.ts:LINE — what it does in one line

Read the full file on GitHub · 80 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 · 80 lines · 19 tokens per session scan A af3d2659def3

Subscribe to this mod's changes

update-code-index is a command published in the GitHub repository brain-bootstrap/claude-code-brain-bootstrap (11 stars, last pushed 4mo ago), licensed MIT. It adds 19 tokens to every session and 689 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 2026-08-30.