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 vinzscam/backstage-skills --skill creating-backstage-scaffolder-fieldgit clone --depth 1 https://github.com/vinzscam/backstage-skillsWrote 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/vinzscam/backstage-skills/creating-backstage-scaffolder-field)<a href="https://agentmods.dev/skills/vinzscam/backstage-skills/creating-backstage-scaffolder-field"><img src="https://agentmods.dev/badge/skills/vinzscam/backstage-skills/creating-backstage-scaffolder-field/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/vinzscam/backstage-skills/creating-backstage-scaffolder-field"><img src="https://agentmods.dev/badge/skills/vinzscam/backstage-skills/creating-backstage-scaffolder-field.svg" alt="Reviewed on agentmods" width="80" 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 | $0.00116 | $0.00942 |
| Opus 5 | $0.00058 | $0.00471 |
| Sonnet 5 | $0.00023 | $0.00188 |
| Haiku 4.5 | $0.00012 | $0.00094 |
Grade A, and why
creating-backstage-scaffolder-field 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 11d 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 — 48 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Creating a Backstage Scaffolder Form Field
When to use this skill
- Building a custom React component that scaffolder template forms can use via
ui:field: '<YourName>' - Editing an existing scaffolder field extension
- The user wants something the built-in fields (
EntityNamePicker,EntityPicker,OwnerPicker,RepoUrlPicker, etc.) don't cover — e.g. a picker that queries a domain-specific external system, a constrained text input with custom validation, a multi-step composite field
What you build
A scaffolder field is a React component plus three pieces of metadata (name, schema, optional validation) wrapped together into a FormField via createFormField. The FormField is then registered as a plugin extension via FormFieldBlueprint.make, listed in the plugin's extensions array.
Three-layer structure:
- The component — a React component receiving
FieldExtensionComponentProps<TValue, TUiOptions>and rendering the input UI. - The schema — a
makeFieldSchema({ output, uiOptions? })Zod schema declaring the field's stored value type and optional UI options. - The blueprint extension —
FormFieldBlueprint.make({ name, params: { field: () => Promise<FormField> } })so the field is discovered by the scaffolder and exposed under the name templates reference inui:field.
For an adopter, the typical container is a frontend-plugin-module that targets the scaffolder, scaffolded via yarn new --select frontend-plugin-module. A standalone frontend plugin can also expose fields via the same blueprint.
Choose the right pattern
| Building... | Reference |
|---|---|
| The field's React component | references/field-component.md |
The field's Zod schema (makeFieldSchema) |
references/field-schema.md |
| Optional validation function | references/field-validation.md |
Plugin/module wiring (createFormField + FormFieldBlueprint) |
references/field-registration.md |
What ships with it
4 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.
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.
- 11d ago First seen · 48 lines · 0 tokens per session scan A ce5b896d3306
creating-backstage-scaffolder-field is a skill published in the GitHub repository vinzscam/backstage-skills (4 stars, last pushed 16d ago), licensed Apache-2.0. It adds 116 tokens to every session and 942 once invoked, about $0.0006 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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