explain

A command for explaining a file, function, or concept in the context of a codebase. It locates definitions and callers, then summarizes what the code is, how it works, and why it matters.

In plain words
What is it for?
Use it to explain paths, symbols, public APIs, callers, contracts, and versioning concerns in an existing codebase.
Why use it?
It reduces the time needed to understand unfamiliar code and makes the explanation evidence-based with file-and-line references. It also identifies related files worth reading next.

Command

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/juliusbrussee/caveman-code/explain
Clone the repo
git clone --depth 1 https://github.com/JuliusBrussee/caveman-code
Per session 16 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 245 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 $0.00016 $0.00245
Opus 5 $0.00008 $0.00122
Sonnet 5 $0.00003 $0.00049
Haiku 4.5 $0.00002 $0.00024

Measured yesterday against content hash 841b02812c97, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

explain 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.

packages/coding-agent/commands/explain.md · 28 lines

What it actually says

Explain $ARGUMENTS in the context of this codebase.

  1. If the argument looks like a path, read it. If it looks like a symbol, use grep to locate definitions and call sites.
  2. Summarise the answer in three layers:
    • What it is — one sentence.
    • How it works — bullet list, ≤ 6 items, with concrete file:line references.
    • Why it matters / who calls it — list upstream callers and the contract they rely on.
  3. If the symbol is part of a public API, also mention versioning concerns.
  4. End with a short list of "Things to read next" — adjacent files the user would benefit from skimming.

Avoid speculation: if you can't find the symbol or file, say so explicitly and suggest a grep query that might find it.

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 · 28 lines · 16 tokens per session scan A 841b02812c97

Subscribe to this mod's changes

explain is a command published in the GitHub repository JuliusBrussee/caveman-code (929 stars, last pushed 17d ago), licensed MIT. It adds 16 tokens to every session and 245 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.