Lens Parameters

Parameters let a Lens accept typed inputs at run time, making it reusable across many instances of the same task.

Syntax

Use double square brackets in the Lens body: [[Parameter Label]]

Translate the following text from [[Source Language]] to [[Target Language]]:

[[Text to Translate]]

Allowed label characters

Feature	Syntax	Example
Single word	[[word]]	[[topic]]
Multi-word (spaces allowed)	[[word word]]	[[Visual Tone]], [[Target Audience]]
Underscores / hyphens	[[word_word]] or [[word-word]]	[[word_count]], [[source-language]]
Optional parameter	[[label!]]	[[Special Instructions!]]
Inline type hint	[[label:type]]	[[Input PDF:file]], [[Word Count:number]]
Type + optional	[[label:type!]]	[[Notes:textarea!]]

The first character must be a letter or digit. Leading/trailing spaces inside the brackets are ignored. Labels must not contain : unless you intend a type hint (see below).

Inline type hints

Append :type after the label (before optional !) to suggest a parameter type when the token is first detected. This is an authoring hint only — the canonical type is stored on the Lens version’s tool binding.

Summarize this document: [[Source Document:file]]
Target length: [[Word Count:integer]]
Tone: [[Tone:text!]]

Supported type values match the table in Parameter types (text, file, number, boolean, etc.). If the suffix is not a known type (for example [[ratio:16]]), the whole token is treated as the label ratio:16.

Optional parameters

Append ! immediately before the closing ]] (after an optional :type) to mark a parameter as optional. Users may leave optional parameters blank; the Lens still runs.

Write a [[Word Count]] word article about [[Topic]].
Tone: [[Tone!]]
Things to avoid: [[Things to Avoid!]]

In the example above, [[Tone!]] and [[Things to Avoid!]] are optional — the Lens works even when left blank.

Why square brackets instead of double curly braces?

The pattern is used by many popular template engines (Jinja2, Handlebars, Mustache, Go templates). When a Lens author pastes code or examples that contain syntax, those tokens would accidentally be detected as Lens parameters.

[[name]] is rarely used as a template delimiter in the wild, making it unambiguous: any [[label]] in a Lens body is always an intentional parameter placeholder.

Parameter types

Type	Description	Example
text	Short text input	A name, a word, a phrase
textarea	Multi-line text	A paragraph, code block
number	Numeric value	Temperature, max tokens
integer	Whole number only	Page count, retry limit
float / decimal	Fractional number	Temperature: 0.7
boolean	True/false toggle	Include examples: yes/no
select	One of several options	Language: English/Spanish/French
json	Raw JSON object	Configuration, structured data
url	Validated URL string	Documentation link
date	Date value	Deadline, publish date
datetime	Date + time value	Scheduled run timestamp
file	Single file attachment	PDF, image, CSV
files	Multiple file attachments	Image gallery, several PDFs for multimodal models

Defining parameters

Parameters are defined in the Lens version editor. Each parameter has:

• key — matches the [[label]] placeholder in the body (lowercased, spaces preserved)
• label — displayed in the UI
• type — one of the types above
• required — whether the field must be filled (use [[label!]] syntax to mark optional at authoring time)
• default_value — optional fallback
• help_text — description shown in the tooltip when hovering the parameter chip
• options — for select type, the list of choices
• validation_schema — optional constraints: min/max (numeric), urlScheme (url), allowedMimeTypes (file/files), maxCount / maxFileBytes / maxTotalBytes (files)

files type limits (platform defaults)

Limit	Default
Files per files parameter	10
Files per lab run (all files params)	20
Max size per file	50 MiB
Max total per files parameter	100 MiB
Max total per run	200 MiB
Max multimodal parts per message	20

Per-tool validation_schema may lower these caps. Allowed MIME types default to image/*, application/pdf, audio/*, and video/* unless allowedMimeTypes is set on the tool.

Author with [[Photos:files]] or bind the File Attachments tool in the version editor.

Parameter chips

In the Lens viewer, each [[parameter]] token is rendered as a colored badge. Hovering the badge shows a tooltip with the parameter's type, label, help text, required status, and default value. Each parameter gets a unique color (deterministic by name) so multiple parameters in the same Lens are visually distinct.

Copying prompts with filled parameters

On the Lens lab panel, Copy with Parameters substitutes filled values into the template:

Action	file parameter	files parameter	Use case
Copy with Parameters (default)	One public https:// URL or placeholder	JSON array of public URLs only, e.g. ["https://…","https://…"]	Paste into external AI tools
Internal IDs	One media_object_id UUID	JSON array of UUIDs	LenserFight execution / snapshot

Inside LenserFight, local BYOK runs send multiple attachments as separate multimodal parts (images may be inlined as base64 so providers never fetch 127.0.0.1). Cloud/server runs emit one attachment_binding per file. Copy never includes data: URIs or localhost links for files params.

Local development and unreachable URLs

Signed Supabase Storage URLs on localhost use http://127.0.0.1:54321/.... External AI services cannot open those links. LenserFight applies this order for Copy with Parameters:

1. SUPABASE_PUBLIC_URL — tunnel (ngrok, Cloudflare Tunnel) pointing at your local Supabase API; signed URLs are rewritten to the public host.
2. media-content edge proxy — when MEDIA_CONTENT_PROXY_ENABLED is on (default when WEB_BASE_URL is public), copy uses a short-lived token URL: {SUPABASE_PUBLIC_URL or SUPABASE_URL}/functions/v1/media-content?object_id=...&token=....
3. Placeholder text — if neither applies, file params copy as a note to upload the file manually (no dead localhost link).

Example .env.local for tunneled copy:

SUPABASE_URL=http://127.0.0.1:54321
SUPABASE_PUBLIC_URL=https://your-tunnel.example.com

See also: Storage adapters.

Related

• What is a Lens?
• Lenses in LenserFight
• Connected Lens Workflows
• Glossary