sequences

A documentation tool that draws Mermaid sequence diagrams showing how a request moves between parts of a system, including successful and failed paths. Mermaid is a text-based format for creating diagrams.

In plain words
What is it for?
Use it to document critical feature flows in a software architecture document, including user stories, error branches, and persistence steps.
Why use it?
It makes runtime interactions easier to review and reveals which data reads and writes the design needs. It also connects the written design to database indexing decisions.

Skill for Claude CodeCodex

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/genkovich/sdd/sequences
Any agent
npx skills add genkovich/sdd --skill sequences
Clone the repo
git clone --depth 1 https://github.com/genkovich/sdd

Made for: Claude Code, Codex.

Per session 172 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,752 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 $0.00172 $0.03752
Opus 5 $0.00086 $0.01876
Sonnet 5 $0.00034 $0.00750
Haiku 4.5 $0.00017 $0.00375

Measured 3d ago against content hash 858a094db58a, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

sequences 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 3d 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/sequences/SKILL.md · 87 lines

How it starts

The opening of the file, as written. The whole thing — 87 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Skill: sequences

Draws the runtime view of an already-designed feature: for each critical flow it produces a Mermaid sequenceDiagram block — generic participants, happy path plus the error branches the spec demands — and writes them into docs/features/<slug>/sad.md §6. One flow at a time, user confirms each. The diagrams are the bridge between the static design (§5 building blocks) and the data layer: every persist/read step you draw becomes a hint for the indexes data-model will need.

Diagram labels + §6 prose follow artifact_language — but the existing sad.md's language wins over the setting; Mermaid keywords (sequenceDiagram, participant, alt/else/end) and participant names that name real modules stay English → ../_shared/artifact-language.md.

This skill keeps only its own machinery. Question phrasing is shared../_shared/ask-style.md. Flow count is driven by the spec, not a cap — every §4 user story / §5 acceptance criterion is covered (size may collapse detail, never coverage) → ../_shared/size-matrix.md. Each diagram is confirmed in prose, never as raw Mermaid../_shared/diagram-presentation.md; whether each flow is confirmed per-diagram or written-and-summarized follows the interview-depth setting → ../_shared/interview-depth.md.

Owner

Tech Lead (drives the runtime decomposition). The PM confirms that each drawn flow matches a real user story; a backend engineer flags persist steps that imply a new index.

Inputs

  • <slug> — same feature slug used by every earlier stage.
  • Gate (hard-refuse if missing): docs/features/<slug>/sad.md. The §5 building-block view names the participants; §6 is where flows are written. If sad.md is absent → STOP and point: «run design <slug> first — sequences are written into its §6».
  • (Expected) sad.md frontmatter target_surfaces — picks the participant vocabulary (UI-driven flows for a UI surface). Absent or empty → warn («surfaces undeclared — re-run design, or proceeding as backend-service») and treat as [backend-service] (→ ../_shared/surfaces.md); never silently guess a UI surface.
  • (Optional) docs/features/<slug>/ux-flows.md — when it exists, the UI-driven flows drawn here agree with it: the <ui> steps follow the same screen path, and a flow may reference the SCR-NN id in a note; a divergence between a §6 flow and a ux-flow is surfaced, never silently drawn over.
  • Strongly expected: docs/features/<slug>/spec.md — §4 user stories tell you which flows exist; §5 acceptance criteria are the coverage floor — every AC must be shown by a flow, a branch, or an explicit non-runtime N/A (the step-7 coverage check). Present by this stage in the normal pipeline; if genuinely absent, fall back to §6/§5 of sad.md for the flow list and note that AC-coverage can't be verified.
  • (Optional) docs/features/<slug>/.size — depth hint for detail (XS/S may collapse a flow's internal steps), never for coverage. Absent → default to M and say so loudly in the handoff — «size M (default — no .size; run /sdd:classify-size <slug>)».
  • (Optional) .claude/sdd.local.md interview_depth (else medium) — governs only the diagram-confirmation UX (per-diagram prose+ask vs. write+summarize-and-proceed); sequences does not open its own depth question (it honors the setting, or a --depth= arg if passed).

Read the full file on GitHub · 87 lines

Files

What ships with it

1 file 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. 3d ago First seen · 87 lines · 172 tokens per session scan A 858a094db58a

Subscribe to this mod's changes

sequences is a skill published in the GitHub repository genkovich/sdd (118 stars, last pushed 14d ago), licensed MIT. It adds 172 tokens to every session and 3,752 once invoked, about $0.0009 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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