Hammock

Hammock is a skill for Claude Code, Codex from adrianleb/hammock-skill. It costs 87 tokens per session (1,740 once invoked), scanned A, original, MIT.

A deliberate design and planning method based on Rich Hickey’s Hammock Driven Development. It encourages understanding the problem before writing code.

In plain words
What is it for?
Use it for new features, difficult bugs, architecture choices, refactors, and detailed plan reviews.
Why use it?
It helps prevent bugs and rework caused by incorrect assumptions about the problem or system design.

Skill for Claude CodeCodex

Part of the hammock plugin — 1 skill shipped together

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 skills/adrianleb/hammock-skill/hammock
Any agent
npx skills add adrianleb/hammock-skill --skill hammock
Clone the repo
git clone --depth 1 https://github.com/adrianleb/hammock-skill

Made for: Claude Code, Codex.

Or install hammock, the plugin that ships this one along with the rest of its 1 skill.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for Hammock

README.md
[![agentmods](https://agentmods.dev/badge/skills/adrianleb/hammock-skill/hammock.svg)](https://agentmods.dev/skills/adrianleb/hammock-skill/hammock)
Your own site
<a href="https://agentmods.dev/skills/adrianleb/hammock-skill/hammock"><img src="https://agentmods.dev/badge/skills/adrianleb/hammock-skill/hammock.svg" alt="Measured on agentmods" height="20"></a>
Per session 87 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,740 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 5.1 $0.00087 $0.01740
Opus 5 $0.00044 $0.00870
Sonnet 5 $0.00017 $0.00348
Haiku 4.5 $0.00009 $0.00174

Measured 5d ago against content hash 5da89b634e50, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, from the pricing page.

Security

Grade A, and why

Hammock 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 5d 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/hammock/SKILL.md · 261 lines

How it starts

The opening of the file, as written. The whole thing — 261 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Hammock Driven Development

A methodology for solving hard problems through deliberate thinking. Most bugs come from misconception, not typos. The cheapest place to fix bugs is during design.

Interactive Process

Use AskUserQuestion tool throughout this process to gather information efficiently. Batch related questions together (max 4 per call). This creates a structured dialogue rather than free-form back-and-forth.

Quick Start

Use AskUserQuestion to determine mode and project type:

Question 1: "What type of design work is this?"
Header: "Project type"
Options:
- New project: "Starting something from scratch"
- New feature: "Adding new capability to existing system"
- Bug investigation: "Finding root cause of an issue"
- Architecture decision: "Significant structural change"
- Refactor: "Improving existing code structure"
- Plan review: "Review an existing design or proposal"

Question 2: "How deep should we go?"
Header: "Mode"
Options:
- Quick: "Problem → Understand → Tradeoffs (time pressure)"
- Standard (Recommended): "Full process without hammock pauses"
- Deep: "Include hammock time prompts for major decisions"

The Process

Phase 1: State the Problem

Use AskUserQuestion:

Question: "What problem are we actually solving? (Describe the pain, not the feature)"
Header: "Problem"
Options:
- [Let user type - use "Other" flow]

Question: "How will we know this is solved?"
Header: "Success"
Options:
- [Let user type - use "Other" flow]

If user gives a feature instead of a problem, probe deeper:

Question: "You mentioned [feature]. What pain or issue does this address?"
Header: "Root problem"

Write the problem statement explicitly before proceeding.

Phase 2: Understand the Problem

First, explore the codebase silently using Glob, Grep, Read tools. Then use AskUserQuestion to fill gaps:

Question: "What constraints must we respect?"
Header: "Constraints"
Options:
- Performance critical: "Has latency/throughput requirements"
- Security sensitive: "Handles auth, PII, or secrets"
- Backward compatible: "Must not break existing clients"
- Time constrained: "Has a deadline"
multiSelect: true

Question: "What's unclear that we should research?"
Header: "Unknowns"
Options:
- [Based on exploration findings, offer specific unknowns discovered]
- [Or let user type]

Read the full file on GitHub · 261 lines

Files

What ships with it

7 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 5d ago First seen · 261 lines · 87 tokens per session scan A 5da89b634e50

Subscribe to this mod's changes

Hammock is a skill published in the GitHub repository adrianleb/hammock-skill (11 stars, last pushed 6mo ago), licensed MIT. It adds 87 tokens to every session and 1,740 once invoked, about $0.0004 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.