web-backend-spec

web-backend-spec is a skill for Claude Code, Codex from howar31/magi-workflow. It costs 84 tokens per session (1,682 once invoked), scanned A, original, MIT.

A skill that adds a backend section to a sprint specification, tailored to the project’s detected web framework and programming stack.

In plain words
What is it for?
Use it to document API contracts, data-model changes, authentication and permissions, validation, monitoring, and contract tests, with user confirmation before proceeding.
Why use it?
It fills in backend details that are often missing from a general specification before production coding begins.

Skill for Claude CodeCodex

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 magi plugin — 15 skills, 2 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 skills/howar31/magi-workflow/web-backend-spec
Any agent
npx skills add howar31/magi-workflow --skill web-backend-spec
Clone the repo
git clone --depth 1 https://github.com/howar31/magi-workflow

Made for: Claude Code, Codex.

Or install magi, the plugin that ships this one along with the rest of its 15 skills, 2 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 web-backend-spec

README.md
[![agentmods](https://agentmods.dev/badge/skills/howar31/magi-workflow/web-backend-spec.svg)](https://agentmods.dev/skills/howar31/magi-workflow/web-backend-spec)
Your own site
<a href="https://agentmods.dev/skills/howar31/magi-workflow/web-backend-spec"><img src="https://agentmods.dev/badge/skills/howar31/magi-workflow/web-backend-spec.svg" alt="Measured on agentmods" height="20"></a>
Per session 84 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,682 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 $0.00084 $0.01682
Opus 5 $0.00042 $0.00841
Sonnet 5 $0.00017 $0.00336
Haiku 4.5 $0.00008 $0.00168

Measured 4d ago against content hash 792e0914042f, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

web-backend-spec 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.

skills/web-backend-spec/SKILL.md · 191 lines

How it starts

The opening of the file, as written. The whole thing — 191 lines — stays where its author put it; the contents beside it link to each section on GitHub.

/magi:web-backend-spec — backend elaboration

You are the coordinator. Add a backend-specific section to a sprint's SPEC.md. You do not write production code. Read references/domain/web/backend.md before starting.

0. Preflight

PLUGIN_ROOT="${CLAUDE_PLUGIN_ROOT:-}"
[[ -z "$PLUGIN_ROOT" ]] && PLUGIN_ROOT="$(cd "$(dirname "$BASH_SOURCE[0]")/../.." 2>/dev/null && pwd)"
USER_CONFIG="$HOME/.config/magi-workflow/config.json"

If config missing → tell user to run /magi:setup.

0.5. State preflight (auto-refuse if not allowed)

STATE_JSON=$(bash "$PLUGIN_ROOT/scripts/shared/detect-state.sh")
blocked=$(jq -r '.disallowed_skills["web-backend-spec"] // empty' <<<"$STATE_JSON")
if [[ -n "$blocked" ]]; then
  reason=$(jq -r '.disallowed_skills["web-backend-spec"].reason' <<<"$STATE_JSON")
  suggest=$(jq -r '.disallowed_skills["web-backend-spec"].suggest' <<<"$STATE_JSON")
  echo "Cannot run /magi:web-backend-spec: $reason"
  echo "Suggested: $suggest"
  exit 1
fi

--force skips preflight (advanced/recovery only).

1. Locate sprint + spec

Find the sprint folder (default: most recent; or --sprint <num>-<slug>). The folder must contain a plan-equivalent file. Identify which exists (priority order):

  • If SPEC.md exists → use SPEC.md as the target.
  • If only PLAN.md exists → use PLAN.md as the target. Do NOT rename or "upgrade" PLAN.md to SPEC.md — that is a separate decision the user makes via /magi:plan, not forced by web-* skills.
  • If only TICKET.md exists → use TICKET.md as the target.
  • If none exists → abort and tell the user to run /magi:plan first.

2. Detect stack

Per references/domain/web/backend.md "Stack discovery". Capture:

  • Web framework (Express / Fastify / Next route handlers / FastAPI / Django / Rails / Go net/http / etc.)
  • Language (TS / Python / Go / Rust / Ruby)
  • ORM (Prisma / TypeORM / SQLAlchemy / GORM / Active Record)
  • DB (Postgres / MySQL / SQLite / Mongo / Redis)
  • Auth scheme (JWT / session / OAuth proxy)
  • API style (REST / GraphQL / gRPC / tRPC)
  • Background jobs (BullMQ / Sidekiq / Celery / Cloud Tasks / k8s CronJob)

Read the full file on GitHub · 191 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 · 191 lines · 84 tokens per session scan A 792e0914042f

Subscribe to this mod's changes

web-backend-spec is a skill published in the GitHub repository howar31/magi-workflow (2 stars, last pushed 5d ago), licensed MIT. It adds 84 tokens to every session and 1,682 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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