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.
npx agentmods add skills/rubenzarroca/sdd-plugin/sdd-plannpx skills add rubenzarroca/sdd-plugin --skill sdd-plangit clone --depth 1 https://github.com/rubenzarroca/sdd-pluginWrote 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.
[](https://agentmods.dev/skills/rubenzarroca/sdd-plugin/sdd-plan)<a href="https://agentmods.dev/skills/rubenzarroca/sdd-plugin/sdd-plan"><img src="https://agentmods.dev/badge/skills/rubenzarroca/sdd-plugin/sdd-plan.svg" alt="Measured on agentmods" height="20"></a>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 | $0.00067 | $0.02901 |
| Opus 5 | $0.00034 | $0.01451 |
| Sonnet 5 | $0.00013 | $0.00580 |
| Haiku 4.5 | $0.00007 | $0.00290 |
Grade A, and why
sdd-plan 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 6d 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.
How it starts
The opening of the file, as written. The whole thing — 255 lines — stays where its author put it; the contents beside it link to each section on GitHub.
/sdd:plan — Design the technical approach
You are designing the technical approach for a feature that has been fully specified and clarified. Follow these steps exactly, in order. Do NOT skip steps. Do NOT read source code — only spec.md, constitution.md, and state.json. Source code analysis belongs to the tasks phase.
Coaching Layer
In sdd-plan, the user shifts from input provider to output consumer — they must evaluate a technical document they didn't write. Claude must bridge this gap.
Rules for presenting technical content:
- Translate to business impact — calibrated to experience. Read
.sdd/state.jsonfieldcompleted_features. On the first feature (0), translate every technical concept to business impact: not "SSR has better SEO" but "Server-side rendering means Google can read your pages." On subsequent features, translate only novel or complex concepts — the user has built vocabulary through previous features. Never re-explain concepts the user has already engaged with. - Explain trade-offs in functional terms. Not "higher coupling" but "these two pieces depend on each other, so changing one means changing both."
- Give the user evaluation criteria — calibrated. Read
.sdd/state.jsonfieldcompleted_features.0: Full evaluation criteria: "When reviewing this plan, focus on three things: (1) Does the data flow match how you described the feature? (2) Are there risks that feel too high for this stage? (3) Is there anything you don't understand? It's better to ask now than to discover a misunderstanding during implementation." Then add: "The more you engage here — catching risks, questioning decisions, suggesting changes — the more I calibrate to your level and move faster in future features."1: Brief reminder: "Same three things to check — data flow, risks, and anything unclear."2+: Skip the criteria. Just ask: "Does this match what you had in mind?"
- Explain what an ADR is on the user's first feature. Check
.sdd/state.jsonfieldmilestones.adr_explained. Iffalse, explain: "An ADR (Architecture Decision Record) is a short document that records why we chose this approach. It's useful when someone asks 'why was it built this way?' six months from now." Then setmilestones.adr_explainedtotruein state.json. If alreadytrue, skip the explanation.
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.
- 6d ago First seen · 255 lines · 67 tokens per session scan A 247196b986d7
sdd-plan is a skill published in the GitHub repository rubenzarroca/sdd-plugin (6 stars, last pushed 6mo ago), licensed MIT. It adds 67 tokens to every session and 2,901 once invoked, about $0.0003 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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