Prompt Template Builder

Write reusable prompts with {{variables}}, fill them in, and copy the compiled result — saved locally in your browser

    Template

    Description: General code review · Model: claude-sonnet-5

    Try a sample:

    Template catalog

    Your library

    Versioned JSON · merges into your library

    Saved templates appear here and persist in your browser across visits.

    Compiled prompt

    Review the following {{language}} code against {{standard}} best practices.

Identify issues grouped by severity (critical, warning, suggestion) and propose concrete fixes.

```
{{code}}
```
    Hard-coding prompts into code or scattering them across notebooks makes them hard to reuse and version. The Prompt Template Builder is a lightweight, browser-based prompt manager: write a template once using {{variable}} placeholders, and the tool detects every variable and renders an input for each. Fill them in and the compiled prompt updates live — then copy it straight into Claude, ChatGPT or your application. Templates can carry optional YAML-like frontmatter (a description, which model they are tuned for) and your whole library is saved to your browser's local storage, so you can save, reload, duplicate and delete prompts without an account or a server. There is no model behind this tool and no API key is ever needed — it only compiles text. Pair it with the Context Assembler to drop a whole codebase into a template variable.

    Examples

    A parameterised code-review prompt

    Template:
Review the following {{language}} code against {{standard}} best practices.
Return issues grouped by severity.

Variables detected: language, standard

Compiled (language=Python, standard=PEP 8):
Review the following Python code against PEP 8 best practices.
Return issues grouped by severity.

    Every {{variable}} becomes an input; the compiled prompt fills them in live.

    Frontmatter for metadata

    ---
description: General code review
optimized_for: claude-sonnet-5
---
Review this {{language}} code…

    A leading --- block holds metadata (description, target model). The body below it is the template.

    Reuse across sessions

    💾 Library (saved in your browser)
  • code-review
  • explain-like-im-five
  • refactor-for-readability

    Saved templates persist across visits in local storage — no account, no server.

    Examples

    Summarization template with variables

    Input
    Summarize the following {{format}} for a {{audience}}.
Keep it under {{length}} words.

{{content}}
    Output
    Variables filled:
  format = "release notes"
  audience = "executive"
  length = "100"

→ Summarize the following release notes for an executive.
  Keep it under 100 words. ...

    Every {{variable}} becomes a fill-in field, so the same skeleton serves many summaries.

    About this tool

    Prompt Template Builder turns reusable prompt skeletons into ready-to-paste prompts. Write a template once with {{variables}}, fill the variable values, and copy the compiled prompt — no find-and-replace, no missed placeholders. It is built for developers who run the same prompt shape against many inputs.

    A built-in catalog ships starting points for common LLM tasks (summarization, extraction, classification, translation and code review), and your own templates persist in a local library you can export and import as a versioned JSON file. Everything runs in your browser — there are no model calls, no API keys, and your templates never leave the device.

    How to use

    1. Write or load a template

      Type a template using {{variable}} placeholders, or pick one from the built-in catalog to start from a proven shape.

    2. Fill the variables

      Each placeholder becomes an input field — enter the value once and it is substituted everywhere it appears.

    3. Copy the compiled prompt

      The finished prompt updates live; copy it to paste into any model, notebook or agent.

    4. Save to your library

      Store templates locally and export the library as JSON so you can back it up or move it between machines.

    Use cases

    Standardize team prompts

    Share one reviewed template across a team so everyone sends a consistent prompt shape to the model.

    Parameterized evals

    Run the same prompt against many inputs by swapping variable values, ideal for prompt evaluation harnesses.

    Onboard new workflows fast

    Start from a catalog template for extraction or classification and adapt it to your data in seconds.

    Common mistakes

    Mistake:Using the wrong placeholder syntax.

    Fix:Wrap variable names in double curly braces exactly: {{variable}}. Single braces or $variables are treated as literal text.

    Mistake:Expecting the tool to call the model.

    Fix:This builder only assembles the prompt text — it makes no AI calls and stores no API key. Paste the result into your model or client.

    Mistake:Losing templates on a new machine.

    Fix:Export your library to the versioned JSON file and import it on the other device; custom templates live only in this browser.

    Frequently asked questions

    References & standards

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