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.
npx agentmods add commands/stellarshenson/claude-code-plugins/update-promptgit clone --depth 1 https://github.com/stellarshenson/claude-code-pluginsWrote 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.
[](https://agentmods.dev/commands/stellarshenson/claude-code-plugins/update-prompt)<a href="https://agentmods.dev/commands/stellarshenson/claude-code-plugins/update-prompt"><img src="https://agentmods.dev/badge/commands/stellarshenson/claude-code-plugins/update-prompt.svg" alt="Measured on agentmods" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00018 | $0.00106 |
| Opus 5 | $0.00009 | $0.00053 |
| Sonnet 5 | $0.00004 | $0.00021 |
| Haiku 4.5 | $0.00002 | $0.00011 |
Grade A, and why
update-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 3d 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.
What it actually says
Update Prompt
Invoke the datascience:update-prompt skill and follow it exactly. It owns the whole procedure; this command only routes into it.
Pass the remainder of this invocation through unchanged as the skill's arguments.
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.
- 3d ago First seen · 12 lines · 18 tokens per session scan A d59ed6b9ae0a
update-prompt is a command published in the GitHub repository stellarshenson/claude-code-plugins (3 stars, last pushed 4d ago), licensed MIT. It adds 18 tokens to every session and 106 once invoked, about $0.0001 per session on Opus 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 2026-08-31.
Other commands, from other repositories
prompt
System instructions for writing effective prompts. Apply when generating commands, skills, agents, or any LLM instructions.
prompt-show
Display full details of a saved prompt by ID.
prompt-optimize
Present the efficiency-versus-effectiveness frontier as labelled variants and let the user pick. TRIGGER WHEN: the user wants to review or optimize a prompt, system message, or agent instructions for clarity/tokens/reliability.
audit-prompt
Evaluate an existing prompt for clarity, effectiveness, and edge cases.
prompt-create
Create a new prompt following ground rules.
start-3-1-3
Module 3.1.3: Consistency & Style - Master the Golden Rules of prompting, reference images, and variants.