Getting it into your agent
It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.
git clone --depth 1 https://github.com/twells89/sigma-migration-skillsnpx agentmods add skills/twells89/sigma-migration-skills/sigma-plugin-authoringWrote 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/twells89/sigma-migration-skills/sigma-plugin-authoring)<a href="https://agentmods.dev/skills/twells89/sigma-migration-skills/sigma-plugin-authoring"><img src="https://agentmods.dev/badge/skills/twells89/sigma-migration-skills/sigma-plugin-authoring/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.
<a href="https://agentmods.dev/skills/twells89/sigma-migration-skills/sigma-plugin-authoring"><img src="https://agentmods.dev/badge/skills/twells89/sigma-migration-skills/sigma-plugin-authoring.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00197 | $0.02629 |
| Opus 5 | $0.00098 | $0.01314 |
| Sonnet 5 | $0.00039 | $0.00526 |
| Haiku 4.5 | $0.00020 | $0.00263 |
Grade A, and why
sigma-plugin-authoring 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 12d 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 — 196 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Sigma Plugin Authoring (Recreate-as-Plugin)
Sigma's native element kinds (bar-chart, kpi-chart, table, pivot-table,
point-map, …) cover most dashboards. Some source vizzes don't map to any of
them — a radial/semicircle gauge, a calendar heatmap, a sankey, a custom
ring/dial. For those, recreate the viz as a Sigma custom plugin
(@sigmacomputing/plugin): a single-file web app Sigma hosts inside a
workbook element, wired to real workbook data through an editor-panel
contract you define.
Scope
The plugin lifecycle: build → register → host → embed → bind → verify.
Building the rest of the workbook around the plugin (the data table it reads
from, KPIs/controls alongside it, page layout, the hidden data page) is the
sigma-workbooks skill's job — this skill only covers the plugin-specific
pieces. Authoring the underlying data model is sigma-data-models.
Decision: does this viz need a plugin at all?
Before reaching for this skill, confirm there's genuinely no native fit:
check the sigma-workbooks skill's chart/KPI/table reference and, if still
unsure, query the OpenAPI's kind enum (see that skill's "Consulting the
shapes" section). Only recreate as a plugin when the native surface is a
confirmed miss — plugins carry real lifecycle cost (hosting, registration,
re-registration on URL change) that a native chart doesn't.
The recipe
1. Build the plugin
Single HTML file, vanilla JS, the SDK loaded via
<script src="https://unpkg.com/@sigmacomputing/plugin">. Declare the data
contract with client.config.configureEditorPanel([...]) — one entry per
variable your embed will bind (an element source, one or more column
bindings sourced from it, optional text/number config). Subscribe to the
data, render, and:
- Attach a
ResizeObserverto the render container that fully recomputes and redraws on every resize (not CSS-only scaling) — seereference/plugin-lifecycle.md§5 for why this is non-negotiable. - Include a synthetic fallback so the file renders sensible demo data
when opened standalone (no Sigma
client, or incomplete bound data) — see §6.
What ships with it
11 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.
- examples/gauge-embed.json 267 B
- generated/cline/sigma-plugin-authoring.md 11 KB
- generated/codex/AGENTS.md 11 KB
- generated/continue/sigma-plugin-authoring.md 11 KB
- generated/cursor/rules/sigma-plugin-authoring.mdc 12 KB
- plugins/gauge/index.html 12 KB
- plugins/gauge/README.md 4.6 KB
- reference/patterns.md 14 KB
- reference/plugin-lifecycle.md 15 KB
- reference/sdk-api.md 15 KB
- scripts/test-gauge-plugin-static.rb 2.9 KB runs code
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.
- 12d ago First seen · 196 lines · 197 tokens per session scan A de66d5265dc7
sigma-plugin-authoring is a skill published in the GitHub repository twells89/sigma-migration-skills (16 stars, last pushed yesterday), licensed MIT. It adds 197 tokens to every session and 2,629 once invoked, about $0.0010 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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