composition

A reasoning method that solves problems by combining existing libraries, services, standards, protocols, and other proven building blocks. The custom work is limited to connecting those parts.

In plain words
What is it for?
Use it to design software by surveying available building blocks, selecting the smallest useful combination, and defining the glue between them.
Why use it?
It reduces unnecessary new development and encourages reuse of tools that already solve part of the problem. It also highlights the risk that connecting many existing parts can become complicated.

Agent

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 agents/jhostalek/dotclaude/composition
Clone the repo
git clone --depth 1 https://github.com/JHostalek/dotclaude
Per session 0 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 140 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 $0.00000 $0.00140
Opus 5 $0.00000 $0.00070
Sonnet 5 $0.00000 $0.00028
Haiku 4.5 $0.00000 $0.00014

Measured 2d ago against content hash 06862209823a, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

composition 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.

skills/design/agents/composition.md · 8 lines

What it actually says

Composition / Existing Primitives Explorer

Your reasoning method: compose existing, proven building blocks rather than building from scratch. The novel part of your design is ONLY the glue connecting them; everything else is borrowed.

Survey what already exists — libraries, services, patterns, protocols, standards, OSS. Find the smallest set of existing primitives that, combined, solve the whole problem. The most elegant answer is often "just use [existing thing] + [existing thing] connected by [thin glue]."

Your blind spot — counter it: constraining yourself to existing tools when a custom solution would be simpler overall. Glue can become its own complexity. Existing tools drag in their own assumptions.

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 · 8 lines · 0 tokens per session scan A 06862209823a

Subscribe to this mod's changes

composition is an agent published in the GitHub repository JHostalek/dotclaude (11 stars, last pushed 28d ago), licensed CC0-1.0. It costs nothing until one of its globs matches a file; then it loads 140 tokens. 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 2026-08-31.

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