sdlc-brief

sdlc-brief is a skill for Claude Code from Jarroslav/agentic-os. It costs 210 tokens per session (4,259 once invoked), scanned C, original, Apache-2.0.

A lightweight software-development workflow for tasks already sized as extra-small, small, or medium. TDD means writing or considering tests as part of development; this workflow also includes planning, review, and checks.

In plain words
What is it for?
Use it for brainstorming, writing a specification, planning, inline TDD, one code-review round, and running checks on the current feature branch.
Why use it?
It gives moderately sized tasks a consistent process without the heavier audit trail and isolated workspaces of a larger workflow.

Skill for Claude Code

Written for Claude Code: Claude Code plugin machinery. Also seen: mentions subagents; names the TodoWrite tool.

Part of the agentic-sdlc plugin — 27 skills, 5 agents shipped together

Good fit Use it for brainstorming, writing a specification, planning, inline TDD, one code-review round, and running checks on the current feature branch.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/jarroslav/agentic-os/sdlc-brief
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.

Any agent
npx skills add Jarroslav/agentic-os --skill sdlc-brief
Clone the repo
git clone --depth 1 https://github.com/Jarroslav/agentic-os

Made for: Claude Code.

Or install agentic-sdlc, the plugin that ships this one along with the rest of its 27 skills, 5 agents.

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 sdlc-brief

README.md
[![agentmods](https://agentmods.dev/badge/skills/jarroslav/agentic-os/sdlc-brief/github.svg)](https://agentmods.dev/skills/jarroslav/agentic-os/sdlc-brief)
Your own site
<a href="https://agentmods.dev/skills/jarroslav/agentic-os/sdlc-brief"><img src="https://agentmods.dev/badge/skills/jarroslav/agentic-os/sdlc-brief/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for sdlc-brief

Your own site · 80×15
<a href="https://agentmods.dev/skills/jarroslav/agentic-os/sdlc-brief"><img src="https://agentmods.dev/badge/skills/jarroslav/agentic-os/sdlc-brief.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 210 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,259 The whole file, excluding the scripts and references it only reads on demand.
Security scan C 1 finding. A grade says what 26 rules found in the file — not that it is safe.
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 $0.00210 $0.04259
Opus 5 $0.00105 $0.02129
Sonnet 5 $0.00042 $0.00852
Haiku 4.5 $0.00021 $0.00426

Measured 9d ago against content hash 8c4272c43978, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade C, and why

sdlc-brief scanned grade C with 1 finding 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 9d 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.

Tells the agent never to refusehighAnti-refusal

Suppressing the ability to decline removes a core safety control; a later harmful request then succeeds.

and continue — never refuse.
plugins/agentic-sdlc/skills/sdlc-brief/SKILL.md · 297 lines

How it starts

The opening of the file, as written. The whole thing — 297 lines — stays where its author put it; the contents beside it link to each section on GitHub.

sdlc-brief

Lightweight orchestrator for tasks a human has already sized as XS/S/M. Picking this skill is the complexity classification — there is no classifier inside it. Everything runs inline, in the current conversation, on the current feature branch.

Cost tradeoff: the full pipeline (sdlc-engine, invoked via sdlc-guided / sdlc-auto) buys audit depth with subagents-per-plan-task, an evidence trail, and worktree isolation. sdlc-brief spends none of that budget. If a task turns out to need it mid-flow, stop and hand it back rather than bolting the heavy machinery on partway through.

Entry points into the parent plugin

Use case Entry point
Ticket-sized, ambiguity expected, full audit trail sdlc-guided
Ticket-sized, low-touch automation, audit trail sdlc-auto
Pre-classified XS/S/M, minimum ceremony sdlc-brief (this skill)
Simple/clear, research-first, no spec sdlc-direct

When the project owns implementation

Before any implementation, read .agentic/agentic-sdlc/config.json if it is there. Where it declares project orchestrators, this skill owns intake, research, spec, plan, review and QA — and nothing that writes code. Route the code-writing to the selected project orchestrator and consume only its summary and gate results. Do not invoke the project's fleet workers yourself, and do not open a competing orchestration state file; the project's own is authoritative for the work it is running.

Non-goals

  • No effort-sizing step of its own — sizing-analyst only returns a routing verdict, never a gate.
  • No meta.json, no per-phase status slots.
  • No run ledger beyond the optional decisions.jsonl / events.jsonl that gate-arbiter writes on its own.
  • No git worktrees under any host.
  • No load of the heavy-pipeline memory directory (.agents/memory/sdlc/) — never read by this skill, in any stage, in any mode.
  • No autonomous or stand-in approval at any judgment gate — HITL only, always.
  • No per-task evidence/*.json — the conversation transcript is the record.
  • No feature verification unless the ui input is explicitly true.

Read the full file on GitHub · 297 lines

Files

What ships with it

2 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. 9d ago First seen · 297 lines · 210 tokens per session scan C 8c4272c43978

Subscribe to this mod's changes

sdlc-brief is a skill published in the GitHub repository Jarroslav/agentic-os (0 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 210 tokens to every session and 4,259 once invoked, about $0.0011 per session on Opus 5. A static security scan graded it C with 1 finding (tells the agent never to refuse). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.