PortalJS is a framework for building data portals that present searchable datasets through a home page, catalog, and dataset showcase. It is for teams that want to choose a data backend, scaffold a Next.js portal, load CSV or JSON data, connect services such as CKAN, and deploy the result. The catalogue entries are agent commands, skills, instructions, and a plugin that guide portal creation and data loading.
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 skills add datopian/portaljs --skill portaljs-add-dcatgit clone --depth 1 https://github.com/datopian/portaljsWrote 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/datopian/portaljs/portaljs-add-dcat)<a href="https://agentmods.dev/skills/datopian/portaljs/portaljs-add-dcat"><img src="https://agentmods.dev/badge/skills/datopian/portaljs/portaljs-add-dcat/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/datopian/portaljs/portaljs-add-dcat"><img src="https://agentmods.dev/badge/skills/datopian/portaljs/portaljs-add-dcat.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 2 findings, up to medium
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- medium MCP Rug Pull · line 67 npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.Fix: Pin the version: npx @scope/[email protected]
- medium MCP Rug Pull · line 80 npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.Fix: Pin the version: npx @scope/[email protected]
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 | $0.00099 | $0.01970 |
| Opus 5.5 | $0.00040 | $0.00788 |
| Sonnet 5.5 | $0.00020 | $0.00394 |
| Haiku 4.5 | $0.00010 | $0.00197 |
Grade A, and why
portaljs-add-dcat 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 7d 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 — 137 lines — stays where its author put it; the contents beside it link to each section on GitHub.
PortalJS — Add DCAT
Overview
Turn an existing PortalJS (portaljs-catalog) portal into a harvestable data catalog.
PortalJS is Frictionless-native — a dataset is a Data Package (see
portaljs-define-schema) — and DCAT is the serialization + harvest layer on top
(lib/metadata/dcat.ts + lib/metadata/dcat-profiles.ts). This skill selects one or
more DCAT application profiles, maps every dataset's metadata to them, and writes
static feed files at build time — JSON-LD, Turtle, and RDF/XML — so external catalogs
(data.europa.eu, data.gov, national portals) can harvest the datasets automatically,
on any static host, with no runtime.
Prerequisites
- A scaffolded PortalJS portal with
datasets.json,package.json, andlib/metadata/(the metadata-profile contract) present. lib/metadata/dcat.ts(the DCAT-3 core) already in place — profiles augment it.- Node 18+ and npm available in the portal directory.
- For DCAT-AP / DCAT-US: a publishing organization (name + homepage) and a contact
(name + email) — both profiles require
dct:publisheranddcat:contactPoint. - Optional but recommended: network access to run SHACL conformance checks against the
official EU ITB validator or
pyshacl.
Instructions
The canonical, full step-by-step workflow is
.claude/commands/portaljs-add-dcat.md —
the single source of truth. Read and follow it when executing. Summary:
- Gather input from
$ARGUMENTS(interview if thin): portal directory (default.), profiles (default["dcat-3"]), site URL, publisher, contact, license, themes, languages, access level. - Validate the portal directory: confirm
datasets.json,package.json, andlib/metadata/exist; stop with anERROR:if the metadata contract is missing. - Ensure the DCAT profile layer is present —
dcat-profiles.ts,dcat-rdf.ts,dcat-validate.ts— copying canonical versions fromexamples/portaljs-catalogif the portal predates this skill. - Ensure
scripts/generate-dcat.tsis wired topredev/prebuildand emits per-profile x serialization feeds fromdcat.config.json. - Write
dcat.config.jsonwith the gathered profiles, publisher, contact, license, themes, and access level. - Add feed autodiscovery: a
<link rel="alternate" type="application/ld+json">topages/_document.tsxpointing at/catalog.jsonld. - Generate the feeds and check conformance: run
npm run generate:dcatand surface any missing mandatory fields. - Verify the RDF: confirm the JSON-LD parses, and cross-check that JSON-LD, Turtle,
and RDF/XML agree; run SHACL validation (ITB for DCAT-AP,
pyshaclfor DCAT-US) when network/tooling allow. - Verify the build with
npx next build; fix errors before reporting success. - Report the profiles emitted, feed paths, conformance status, and next steps
(register with the harvester, run
portaljs-deploy).
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.
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.
- 7d ago Changed 162867a97591
- 1mo ago First seen · 137 lines · 99 tokens per session scan A dad56c7044f7
portaljs-add-dcat is a skill published in the GitHub repository datopian/portaljs (2,370 stars, last pushed today), licensed MIT. It adds 99 tokens to every session and 1,970 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.
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