sdlc-spike

sdlc-spike is a command for coding agents from MCKRUZ/claude-code-sdlc. It costs 0 tokens per session (1,213 once invoked), scanned A, original, MIT.

A command for opening a short research task when a software requirement depends on an answer nobody has verified yet. The result is a written finding, not production code.

In plain words
What is it for?
It is for checking unknown integration behavior, testing design assumptions, or resolving conflicting acceptance criteria before development starts.
Why use it?
It prevents teams from writing detailed specifications based on guesses and discovering the missing information only during implementation.

Command

Installs and runs on its own, but its text points at files inside its plugin — anything it tells you to read at a ${CLAUDE_PLUGIN_ROOT} path is only there once the plugin is installed. Installing the plugin gets both.

Part of the claude-code-sdlc plugin — 9 skills, 28 commands, 20 agents 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 commands/mckruz/claude-code-sdlc/sdlc-spike
Clone the repo
git clone --depth 1 https://github.com/MCKRUZ/claude-code-sdlc

Or install claude-code-sdlc, the plugin that ships this one along with the rest of its 9 skills, 28 commands, 20 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-spike

README.md
[![agentmods](https://agentmods.dev/badge/commands/mckruz/claude-code-sdlc/sdlc-spike.svg)](https://agentmods.dev/commands/mckruz/claude-code-sdlc/sdlc-spike)
Your own site
<a href="https://agentmods.dev/commands/mckruz/claude-code-sdlc/sdlc-spike"><img src="https://agentmods.dev/badge/commands/mckruz/claude-code-sdlc/sdlc-spike.svg" alt="Measured on agentmods" height="20"></a>
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 1,213 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 $0.01213
Opus 5 $0.00000 $0.00607
Sonnet 5 $0.00000 $0.00243
Haiku 4.5 $0.00000 $0.00121

Measured 4d ago against content hash df42402dde02, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

sdlc-spike 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 4d 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.

commands/sdlc-spike.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.

/sdlc-spike — Run a Bounded Spike When the Answer Isn't Known Yet

Open a spike (spikes/NNNN-name.md) for a question the pod cannot yet answer. This is the escape hatch for the one situation /sdlc-spec cannot serve: a story that fails the Definition of Ready not because it is badly written, but because nobody knows the answer.

Writing a confident spec about an unknown is the expensive mistake. It reads as ready, the grader grades it against fiction, and the pod finds out at merge. A spike finds out first.

The spike's deliverable is a written finding, not code. The code is thrown away; the finding is committed and outlives the branch.

When this command applies

Use it when an acceptance check cannot be written because the behavior is unverified:

  • An integration's real response is undocumented ("does the carrier API deduplicate on our idempotency key, or do retries create duplicate claims?").
  • A design decision rests on an assumption nobody has tested.
  • Two people at triage wrote two different acceptance lines for the same requirement — the vague-line test failing out loud because the ground truth is missing.

Do not use it as a way to start building without a spec. If the answer is known and the work just feels large, that is a spec (possibly several).

Steps

  1. Confirm it is genuinely an unknown, not a vague line. Ask which acceptance check cannot be written, and why. If the answer is "we know, it just needs wording," stop and run /sdlc-spec instead. Say so plainly rather than opening a spike to avoid the harder conversation.

  2. Get the box and the opener from a human. Both are required, and neither is yours to decide.

    "How long should this be boxed — a time box or a token box? And who is opening it: the Pod Lead at triage, or the Architect on a design decision?"

    A spike with no box is unsupervised building. Claude never decides to spike instead of build.

  3. Name what it unblocks. A decision-list item id, the story that cannot be made ready, or the ADR whose assumption is under test. A spike that unblocks nothing is tinkering.

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. 4d ago First seen · 90 lines · 0 tokens per session scan A df42402dde02

Subscribe to this mod's changes

sdlc-spike is a command published in the GitHub repository MCKRUZ/claude-code-sdlc (4 stars, last pushed 6d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 1,213 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.