tersify-prompt

tersify-prompt is a skill for Claude Code from rp1-run/rp1. It costs 21 tokens per session (707 once invoked), scanned A, original, Apache-2.0.

A prompt-editing skill that shortens instructions for coding agents while keeping their intended meaning. It can work from text or update a prompt file.

In plain words
What is it for?
Use it to compress an inline prompt or a file, then review the shortened version and its change summary.
Why use it?
Long agent instructions can be harder to read and maintain, especially when repeated details obscure the actual task.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the rp1-utils plugin — 4 skills, 1 agent shipped together

Good fit Use it to compress an inline prompt or a file, then review the shortened version and its change summary.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/rp1-run/rp1/tersify-prompt
Install

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.

Any agent
npx skills add rp1-run/rp1 --skill tersify-prompt
Clone the repo
git clone --depth 1 https://github.com/rp1-run/rp1

Made for: Claude Code.

Or install rp1-utils, the plugin that ships this one along with the rest of its 4 skills, 1 agent.

Wrote 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.

agentmods badge for tersify-prompt

README.md
[![agentmods](https://agentmods.dev/badge/skills/rp1-run/rp1/tersify-prompt/github.svg)](https://agentmods.dev/skills/rp1-run/rp1/tersify-prompt)
Your own site
<a href="https://agentmods.dev/skills/rp1-run/rp1/tersify-prompt"><img src="https://agentmods.dev/badge/skills/rp1-run/rp1/tersify-prompt/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.

agentmods 80×15 button for tersify-prompt

Your own site · 80×15
<a href="https://agentmods.dev/skills/rp1-run/rp1/tersify-prompt"><img src="https://agentmods.dev/badge/skills/rp1-run/rp1/tersify-prompt.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 21 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 707 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00021 $0.00707
Opus 5.5 $0.00008 $0.00283
Sonnet 5.5 $0.00004 $0.00141
Haiku 4.5 $0.00002 $0.00071

Measured 1mo ago against content hash fe17c475043f, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

tersify-prompt 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 1mo 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.

plugins/utils/skills/tersify-prompt/SKILL.md · 123 lines

How it starts

The opening of the file, as written. The whole thing — 123 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Tersify Prompt

Compresses agent-instruction prompts to be maximally terse while preserving full intent.

Modes

File Mode (when INPUT is a valid file path):

  1. Read the file content
  2. Pass to tersifier agent
  3. Extract compressed prompt from output
  4. Update the file with compressed version
  5. Display change summary

Inline Mode (when INPUT is prompt text):

  1. Pass prompt directly to tersifier agent
  2. Display compressed prompt and change log

Workflow

Step 1: Detect Mode

Check if INPUT is a file path:

Use Bash: test -f "{INPUT}" && echo "file" || echo "inline"

Step 2: Prepare Input

If file mode:

  • Read the file using Read tool
  • Store the file path for later update
  • Extract file content as INPUT_PROMPT

If inline mode:

  • Use INPUT directly as INPUT_PROMPT

Step 3: Spawn Tersifier Agent

{% dispatch_agent "rp1-utils:prompt-tersifier" %} {INPUT_PROMPT content here} {% enddispatch_agent %}

Step 4: Process Output

The agent returns output in this format:

<<<COMPRESSED_PROMPT
[compressed content]
COMPRESSED_PROMPT>>>

<<<CHANGES
[op] ref: description
  - from: "short excerpt"
  - to: "short excerpt"
  - note: reason

[op] ref: description
  ...
CHANGES>>>

Parse the output:

  • Extract content between <<<COMPRESSED_PROMPT and COMPRESSED_PROMPT>>>
  • Extract the changes list between <<<CHANGES and CHANGES>>>

Step 5: Finalize

If file mode:

  1. Use Write tool to update the original file with the compressed prompt
  2. Display to user:
    Updated: {file_path}
    
    ## Changes Made
    {changes table}
    

If inline mode:

  1. Display to user:
    ## Compressed Prompt
    {compressed prompt}
    
    ## Changes Made
    {changes table}
    

Examples

File mode:

/tersify-prompt plugins/base/agents/kb-spatial-analyzer.md

Output: Updates file in place, shows change summary.

Inline mode:

/tersify-prompt "You are a helpful assistant that helps users write code. Always be polite and thorough in your responses. Make sure to explain your reasoning step by step."

Output: Displays compressed prompt and change log.

Read the full file on GitHub · 123 lines

Changes

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.

  1. 1mo ago First seen · 123 lines · 21 tokens per session scan A fe17c475043f

Subscribe to this mod's changes

tersify-prompt is a skill published in the GitHub repository rp1-run/rp1 (38 stars, last pushed 3d ago), licensed Apache-2.0. It adds 21 tokens to every session and 707 once invoked, about $0.0001 per session on Opus 5.5. 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 2026-09-07.

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