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-define-schemagit 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-define-schema)<a href="https://agentmods.dev/skills/datopian/portaljs/portaljs-define-schema"><img src="https://agentmods.dev/badge/skills/datopian/portaljs/portaljs-define-schema/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-define-schema"><img src="https://agentmods.dev/badge/skills/datopian/portaljs/portaljs-define-schema.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 3 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 Rogue Agent · line 3 Skill establishes unauthorized persistence across sessions via cron jobs, startup scripts, or state files. Session persistence allows an attacker to maintain access beyond the current interaction.Fix: Remove any persistence mechanisms (cron jobs, startup scripts, state files). Skills should not maintain state across sessions without explicit user consent.
- medium MCP Rug Pull · line 71 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 81 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 | $0.00079 | $0.01630 |
| Opus 5 | $0.00039 | $0.00815 |
| Sonnet 5 | $0.00016 | $0.00326 |
| Haiku 4.5 | $0.00008 | $0.00163 |
Grade A, and why
portaljs-define-schema 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 9d 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 — 126 lines — stays where its author put it; the contents beside it link to each section on GitHub.
PortalJS — Define Schema
Overview
Define a dataset's metadata profile — the authoring skill for the metadata-profile
contract (lib/metadata). Where portaljs-add-dataset registers that a dataset exists,
this skill describes what its data means: infer a Frictionless Table Schema (fields,
types, constraints) from sampled data, add the Data Package fields a catalog surfaces
(title, licenses, sources, keywords), and write them onto the dataset's entry in
datasets.json. The showcase at /@<namespace>/<slug> then renders a typed field table
instead of a bare preview. The model is Frictionless-native; DCAT is a serialization layer
built on top later, not authored here.
The skill runs on a profile ladder — reach for higher levels only when needed:
| Level | What it is | When |
|---|---|---|
| L0 | Default frictionless-tabular profile; declare schema + metadata. |
Default. Standard tabular CSV/TSV. |
| L1 | L0 plus extra descriptive package fields. | Extra metadata, standard validation is fine. |
| L2 | Fully custom profile (own schema template + validate()). |
A dataset type needing custom validation rules. |
| L3 | Multiple registered profiles, resolved per dataset. | A portal mixing dataset types. |
The skill is interactive and never dead-ends: if input is thin it interviews in short rounds, infers defaults from the data, echoes the schema for confirmation, and accepts "use defaults" to proceed with the inferred schema as-is.
Prerequisites
- A scaffolded PortalJS portal with the metadata contract (
lib/metadata/types.ts,pages/[owner]/[slug].tsx); seeportaljs-new-portal. - The target dataset already registered in
datasets.json(seeportaljs-add-dataset). - For tabular schema inference, the dataset's CSV/TSV file present under
PORTAL_DIR/public/data/. JSON/GeoJSON datasets get package metadata only — nofields. - Node 18+;
tsxoptional, used for the schema-validation check.
Instructions
The canonical, full step-by-step workflow is
.claude/commands/portaljs-define-schema.md —
the single source of truth. Read and follow it when executing. Summary:
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.
- 9d ago First seen · 126 lines · 79 tokens per session scan A f2c5686b8cd4
portaljs-define-schema is a skill published in the GitHub repository datopian/portaljs (2,349 stars, last pushed yesterday), licensed MIT. It adds 79 tokens to every session and 1,630 once invoked, about $0.0004 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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