Add Knap skill

skills/knap/SKILL.md

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+---
+name: knap
+description: Render Markdown from templates and structured data using Knap CLI. Use when the user asks to apply a Knap template, turn JSON or CSV data into notes, batch-generate Markdown files, or format Defuddle output into a note.
+---
+
+# Knap
+
+Use Knap CLI to render Markdown templates with variables, filters, and logic.
+
+If not installed: `npm install -g knap` (requires Node.js 20 or later). Alternatively, use `npx knap`.
+
+Run `knap --help` for available commands and options. Discover the language through the CLI's offline reference:
+
+```bash
+knap help syntax
+knap help filters
+knap help filter date
+knap help tags
+knap help tag for
+```
+
+Use the lists to find names, then request individual help for syntax, parameters, and examples with expected output.
+
+## Usage
+
+Render a template with JSON variables:
+
+```bash
+knap render template.md --data article.json -o note.md
+```
+
+Supply a template and data inline:
+
+```bash
+knap render -t '# {{ title | trim }}' --data-json '{"title":"Hello"}'
+```
+
+Override a variable or pipe JSON data:
+
+```bash
+knap render template.md --data article.json --set 'title=Custom title'
+cat article.json | knap render template.md --data -
+```
+
+Data must be a JSON object; its properties become template variables. `--set` overrides literal top-level keys with strings. Use JSON for nested objects, arrays, numbers, and booleans.
+
+Choose one template source (file, `-t`, or stdin) and one data source (`--data` or `--data-json`). Only one input can read stdin. Without a template file or `-t`, Knap reads the template from stdin.
+
+Output defaults to stdout. `-o` creates parent directories and overwrites the destination after rendering succeeds. Errors exit with status `1`; diagnostics go to stderr. Warnings can accompany successful output.
+
+## Templates
+
+Use `{{ variable }}` for values, `|` for filters, and `{% ... %}` for logic. For example, save this as `template.md`:
+
+```knap
+---
+{{ title | yaml_property:"title" }}
+{{ tags | yaml_property:"tags" }}
+---
+# {{ title | trim }}
+{% if author %}
+By {{ author }}
+{% endif %}
+
+{{ content }}
+```
+
+Use `yaml_property` for complete frontmatter properties so values are quoted and indented correctly. The CLI includes standard filters, but does not supply Web Clipper browser variables, selectors, prompts, or DOM-dependent HTML filters. Supply variables through JSON.
+
+Check a template before rendering:
+
+```bash
+knap validate template.md
+```
+
+Validation checks syntax, filter names, and static filter arguments without data or file output. It does not check variable existence, runtime values, or dynamic arguments; render with real data to check runtime behavior. Diagnostics go to stderr and include relevant help commands.
+
+## Defuddle pipeline
+
+Extract a web page as JSON with Markdown content, then render it into a note:
+
+```bash
+defuddle parse https://example.com/article --md --json \
+  | knap render template.md --data - -o note.md
+```
+
+Defuddle's JSON properties, such as `title` and `content`, become template variables directly.
+
+## Batch rendering
+
+Create one file per CSV row, JSON array object, or JSON file in a folder:
+
+```bash
+knap batch template.md --data articles.csv --output-dir notes \
+  --filename '{{ title | safe_name }}.md'
+```
+
+Use `--data articles.json` for an array or `--data ./articles` for a folder of JSON objects. CSV headers become variable names and values remain strings. Piped data defaults to JSON; add `--format csv` for piped CSV.
+
+Use `--dry-run` to validate and list output paths without writing files. Existing files require `--overwrite`, including during a dry run. Duplicate output names within a batch are errors even with `--overwrite`.
+
+Filename templates must produce a single filename with its extension, without directories. Use `safe_name` for data-derived names. Without `--filename`, Knap preserves source JSON basenames or numbers CSV rows and array items as `1.md`, `2.md`, and so on.