A Story Driven Development workflow that keeps product and system documentation synchronized with application code. SDD uses Git, a version-control system, to track specification changes.

Use it in projects with a .sdd/config.yaml file to find pending bugs and change requests, update the documented requirements, implement work, and mark it synchronized.

It gives teams a defined way to handle bugs, requested specification changes, implementation work, and synchronization without losing track of what changed.

How sifter-ai/sifter configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to sifter-ai/sifter. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/sifter-ai/sifter/main/.agents/skills/sdd/SKILL.md

Clone the repo

git clone --depth 1 https://github.com/sifter-ai/sifter

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/sifter-ai/sifter/sdd/github.svg)](https://agentmods.dev/skills/sifter-ai/sifter/sdd)

Your own site

<a href="https://agentmods.dev/skills/sifter-ai/sifter/sdd"><img src="https://agentmods.dev/badge/skills/sifter-ai/sifter/sdd/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/sifter-ai/sifter/sdd"><img src="https://agentmods.dev/badge/skills/sifter-ai/sifter/sdd.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 98 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,258 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.

Model	Per session	Once invoked
Fable 5.1	$0.00098	$0.01258
Opus 5.5	$0.00039	$0.00503
Sonnet 5.5	$0.00020	$0.00252
Haiku 4.5	$0.00010	$0.00126

Measured 2mo ago against content hash e4ae532fbf6d, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

sdd 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 2mo 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.

.agents/skills/sdd/SKILL.md · 93 lines

How it starts

The opening of the file, as written. The whole thing — 93 lines — stays where its author put it; the contents beside it link to each section on GitHub.

SDD — Story Driven Development

What this is

SDD keeps documentation (product/, system/) and code (code/) in sync. Specs change → sdd sync surfaces what's pending → agent implements → sdd mark-synced commits the state → repeat.

The engine behind it is git: SDD uses git diff on the doc files to know what changed since the last sync. That's why committing immediately after every mark-synced is non-negotiable — skip a commit and the next sync will see phantom changes.

Detection

This project uses SDD if .sdd/config.yaml exists in the project root.

The core loop

Every session on an SDD project starts the same way — clear the backlog from highest priority down, then move new work forward:

Bugs first. Run sdd bug open. If there are open bugs, fix the code/docs and run sdd mark-bug-resolved. Bugs block everything else.
Then Change Requests. Run sdd cr pending. If there are pending CRs, apply them to the docs in product//system/ (this flips docs to new/changed/deleted), then run sdd mark-cr-applied. CRs are the intended way to modify specs — never edit docs arbitrarily to reflect user requests; turn them into CRs first if scope justifies it.
Then sync. Run sdd sync. It returns a structured prompt listing every pending file and (for changed files) the exact git diff of what changed in the spec. Read only what the prompt tells you to read.
Implement. Write code inside code/ matching what each doc describes. For deleted files, remove the corresponding code — the doc itself gets deleted automatically on mark-synced.
Mark synced + commit. This is one atomic step:

sdd mark-synced                     # or sdd mark-synced <specific files>
git add -A && git commit -m "sdd sync: <what you implemented>"

Every mark-synced MUST be followed by a commit in the same turn. No exceptions. See "Why the commit is mandatory" below.

Publish (if remote configured). If .sdd/config.yaml has a remote: section and an API key is set, remind the user they can push with sdd push.

Read the full file on GitHub · 93 lines

Files

What ships with it

3 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.

2mo ago First seen · 93 lines · 98 tokens per session scan A e4ae532fbf6d

Subscribe to this mod's changes

sdd is a skill published in the GitHub repository sifter-ai/sifter (54 stars, last pushed 1mo ago), licensed MIT. It adds 98 tokens to every session and 1,258 once invoked, about $0.0004 per session on Opus 5.5. 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.

Git and workflow Planning

sdd next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
sddsifter-ai/sifter	Skill	54	1mo ago	MIT	A	98	Claude Code
merge-batchdiegosouzapw/OmniRoute	Skill	83k	5d ago	MIT	A	46	Claude Code
prowler-commitprowler-cloud/prowler	Skill	15k	yesterday	Apache-2.0	A	44	Claude Code, Codex
gh-auth-isolationgithub/gh-aw	Skill	5.6k	yesterday	MIT	A	20	Claude Code, Codex
github-skillzeenie-ai/OpenCompany	Skill	1.1k	yesterday	MIT	A	51	Claude Code
comet-githubrpamis/comet	Skill	3.3k	yesterday	MIT	A	72	Claude Code, Codex
release-helperSahir619/fable-method	Skill	2.3k	1mo ago	MIT	A	43	Claude Code

sifter: Skill for Claude Code