prompt-writer

Prompt Writer

A skill for writing high-quality LLM prompts (especially for Claude), based on close reading of the Claude system prompts (Opus 4.7, Fable 5, Opus 5) and how attention uses a prompt.

When this skill is active

The user wants to create or improve an instruction for an LLM. It can be a system prompt, a role prompt, an agent instruction, a prompt template, a Claude Project setup, or a specific prompt for a repeatable task. The skill follows a process: understand the task → determine the type → apply the template → audit the draft → deliver the final version.

The process

Step 1: Understand the task

If the user gave a detailed spec with examples, goals, audience, and constraints, do NOT ask clarifying questions, start immediately with inline assumptions. Second-guessing a detailed request hurts.

If the spec is vague ("write a prompt for an assistant"), ask the minimum number of questions needed to determine the prompt type. No more than 2-3 questions at a time.

The minimum that has to be known before starting:

• What the prompt is supposed to do
• Which model or tool the prompt is written for. If it is not stated, assume Claude, mark that assumption inline in the result, and do not spend a question on it. The rules of this skill are calibrated for Claude; for other tools they apply as they are, with no adaptation
• What format and length of output the user expects
• The success criterion, how the user will know the prompt worked
• Who will use it (a single user, a team, end customers)
• Whether there are critical prohibitions (what must NEVER happen)
• Whether an existing prompt is being improved

Output format and length and the success criterion are derived from the task; ask about them only when they do not follow from the spec, and within the limit of 2-3 questions.

Step 2: Determine the prompt type

Read the Routing section below and pick one of five types. The type decides the template and the approach.

Step 3: Apply the template