problem-first-impl

problem-first-impl is a skill for Claude Code, Codex from lensapp/lens-sandbox. It costs 83 tokens per session (1,555 once invoked), scanned A, original, Apache-2.0.

An implementation hand-off skill that continues a problem-first requirements session. Gherkin is a plain-language format for describing software behavior in test scenarios.

In plain words
What is it for?
Use it after agreeing on a problem, scenarios, target code area, solution direction, alternatives, and constraints; it writes the scenarios to a feature file and starts technical planning.
Why use it?
It confirms the requested scope against product documentation and existing specifications before technical work begins.

Skill for Claude CodeCodex

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/lensapp/lens-sandbox/problem-first-impl
Any agent
npx skills add lensapp/lens-sandbox --skill problem-first-impl
Clone the repo
git clone --depth 1 https://github.com/lensapp/lens-sandbox

Made for: Claude Code, Codex.

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 problem-first-impl

README.md
[![agentmods](https://agentmods.dev/badge/skills/lensapp/lens-sandbox/problem-first-impl.svg)](https://agentmods.dev/skills/lensapp/lens-sandbox/problem-first-impl)
Your own site
<a href="https://agentmods.dev/skills/lensapp/lens-sandbox/problem-first-impl"><img src="https://agentmods.dev/badge/skills/lensapp/lens-sandbox/problem-first-impl.svg" alt="Measured on agentmods" height="20"></a>
Per session 83 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,555 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 $0.00083 $0.01555
Opus 5 $0.00042 $0.00777
Sonnet 5 $0.00017 $0.00311
Haiku 4.5 $0.00008 $0.00155

Measured today against content hash a702846bbf04, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

problem-first-impl 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 today.

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/skills/problem-first-impl/SKILL.md · 90 lines

How it starts

The opening of the file, as written. The whole thing — 90 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Spec — Problem-First → Implementation

Take the agreed problem + Gherkin scenarios from /problem-first and move to technical planning. This skill does two things: (1) a final scope confirmation against the product docs and existing specs, and (2) hand-off — writing the .feature file and entering plan mode.

This skill is the "code path" continuation. If the goal is to file an issue for someone else to pick up, use /problem-first-issue instead.

Inputs

You need the full output of a /problem-first session, or a GitHub issue carrying the same content:

  1. A problem statement (1-2 sentences).
  2. An agreed set of Gherkin scenarios.
  3. A target crate in this monorepo.
  4. An agreed approach — one-paragraph solution direction from /problem-first Phase 3.
  5. Alternatives considered and their rejection reasons (1-3).
  6. Optionally: assumptions / constraints, non-goals, open questions.

Invocation modes

Mode A — Continuation in the same session as /problem-first. If /problem-first just ran in this conversation, read the full output (problem, scenarios, target crate, approach, alternatives, assumptions) directly from conversation context. Doc-level alignment was confirmed at intake — do not re-run that check. Briefly confirm: "Using the problem, N scenarios, target crate <crate>, and chosen approach from the /problem-first session above (doc-alignment confirmed) — proceeding to code-level check."

Mode B — Standalone (picking up a GitHub issue, or resuming cold). If there is no prior /problem-first output in the session, the user is likely picking up work that was planned earlier. Either:

  • Ask for the source: "Do you have a /problem-first-issue GitHub issue for this? Paste the number or URL and I'll read it (gh issue view <n>), or paste the problem + scenarios + approach directly."
  • Or elicit all six input items above.

In Mode B, product docs may have changed since the issue was filed. Re-run the doc-level alignment check from /problem-first Phase 4 before the code-level check — cheap insurance against silently implementing against stale direction.

Read the full file on GitHub · 90 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. today Changed · -9 lines a702846bbf04
  2. 4d ago First seen · 99 lines · 83 tokens per session scan A 19ed18de9e7b

Subscribe to this mod's changes

problem-first-impl is a skill published in the GitHub repository lensapp/lens-sandbox (10 stars, last pushed yesterday), licensed Apache-2.0. It adds 83 tokens to every session and 1,555 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 2026-08-31.

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