sdd-architecture-scan

sdd-architecture-scan is a command for Claude Code from GregorBiswanger/featherspec. It costs 24 tokens per session (4,259 once invoked), scanned A, original, MIT.

A command for mapping the architecture of an existing codebase by scanning its files in stages. It can pause and continue using saved worklists and reports.

In plain words
What is it for?
Use it to scan the whole project or a selected folder, process pending parts, and merge the findings into an architecture fingerprint.
Why use it?
It turns a large, unfamiliar codebase into an organized record of its structure and design instead of requiring one lengthy manual review.

Command for Claude Code

Written for Claude Code: disable-model-invocation in frontmatter. Also seen: reads .claude/ paths; mentions Claude Code; mentions AGENTS.md.

Good fit Use it to scan the whole project or a selected folder, process pending parts, and merge the findings into an architecture fingerprint.

Compare 6 commands from other repositories ↓
Install with agentmods
npx agentmods add commands/gregorbiswanger/featherspec/sdd-architecture-scan
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.

Clone the repo
git clone --depth 1 https://github.com/GregorBiswanger/featherspec

Made for: Claude Code.

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 sdd-architecture-scan

README.md
[![agentmods](https://agentmods.dev/badge/commands/gregorbiswanger/featherspec/sdd-architecture-scan.svg)](https://agentmods.dev/commands/gregorbiswanger/featherspec/sdd-architecture-scan)
Your own site
<a href="https://agentmods.dev/commands/gregorbiswanger/featherspec/sdd-architecture-scan"><img src="https://agentmods.dev/badge/commands/gregorbiswanger/featherspec/sdd-architecture-scan.svg" alt="Measured on agentmods" height="20"></a>
Per session 24 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 4,259 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. 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 $0.00024 $0.04259
Opus 5 $0.00012 $0.02129
Sonnet 5 $0.00005 $0.00852
Haiku 4.5 $0.00002 $0.00426

Measured 8d ago against content hash 9133e6fd01c2, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

sdd-architecture-scan 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 8d 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.

.claude/commands/sdd-architecture-scan.md · 280 lines

How it starts

The opening of the file, as written. The whole thing — 280 lines — stays where its author put it; the contents beside it link to each section on GitHub.

/sdd-architecture-scan — Deep Architecture Scan

The user may name a focus path after the command; then every phase below applies to that subtree only, and the final merge touches only its entries.

Speak plainly, in DocLanguage, throughout: assume the user has never seen this workflow. Every question and every gate opens with one short line saying why it is asked and what the answer changes, and every term of art (worklist, unit, tier, scout) gets a one-clause introduction on first use. Minimal and precise — one line of why, never a lecture.

Where am I? (state router — the files decide, not the conversation)

  • No .sdd-scan/_worklist.md → run Phase A, then stop at the worklist gate.
  • Worklist exists with pending units → run Phase B on pending units only.
  • All units done but the update merge not yet confirmed → run Phase C. The user saying "distill what we have" also runs Phase C — a full re-distillation from the reports, even after a confirmed merge; refreshing dates or markers alone is not a distillation. Otherwise, after a confirmed merge, a re-invocation has nothing left but the cleanup question.

On a fresh start — say what this buys and costs (once, in DocLanguage)

On a fresh start (no worklist yet) this briefing is the first visible output — before any question and before Phase A runs, and equally when /sdd-setup routed here. Three short, plain points (~6 lines total), then proceed:

  • Value: the fingerprint replaces exploration. Agents in every later session — in both tools — jump straight to the right place instead of searching, and technical planning (specs, reviews, onboarding) starts from a shared, verified map.
  • Cost: the scan is token-intensive — scouts read code in isolated contexts. Name a planning figure (~50k tokens per analysis unit; large repositories multiply), say that cost scales with the models in use and can get expensive, and that a capable model pays off for synthesis while the scouts inherit the session model — choosing a cheaper model for the scan session, or pinning one locally in the scout agent files, is the biggest cost lever.
  • Levers: the worklist gate is the cost dial — defer units (they stay visible under unmapped:), set shallow tiers for periphery, rescan later with a focus path; the scan resumes from its files at any point.

Read the full file on GitHub · 280 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. 8d ago First seen · 280 lines · 24 tokens per session scan A 9133e6fd01c2

Subscribe to this mod's changes

sdd-architecture-scan is a command published in the GitHub repository GregorBiswanger/featherspec (48 stars, last pushed 8d ago), licensed MIT. It adds 24 tokens to every session and 4,259 once invoked, about $0.0001 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.

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