oneshot

oneshot is a skill for Claude Code from coroboros/agent-skills. It costs 59 tokens per session (1,806 once invoked), scanned A, original, MIT.

A single-pass workflow for making one focused code change by exploring the code, writing the change, and testing it.

In plain words
What is it for?
It helps implement quick, narrowly scoped fixes or features and validate them with tests.
Why use it?
It provides a fast path for small tasks while stopping and recommending a more thorough workflow when the task becomes complex.

Skill for Claude Code

Written for Claude Code: argument-hint in frontmatter. Also seen: mentions subagents.

Part of the workflow-skills plugin — 4 skills shipped together

Good fit It helps implement quick, narrowly scoped fixes or features and validate them with tests.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/coroboros/agent-skills/oneshot
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 coroboros/agent-skills --skill oneshot
Clone the repo
git clone --depth 1 https://github.com/coroboros/agent-skills

Made for: Claude Code.

Or install workflow-skills, the plugin that ships this one along with the rest of its 4 skills.

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 oneshot

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

Your own site · 80×15
<a href="https://agentmods.dev/skills/coroboros/agent-skills/oneshot"><img src="https://agentmods.dev/badge/skills/coroboros/agent-skills/oneshot.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 59 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,806 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 $0.00059 $0.01806
Opus 5 $0.00030 $0.00903
Sonnet 5 $0.00012 $0.00361
Haiku 4.5 $0.00006 $0.00181

Measured yesterday against content hash 56117d89a4e9, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

oneshot 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 yesterday.

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.

skills/oneshot/SKILL.md · 146 lines

How it starts

The opening of the file, as written. The whole thing — 146 lines — stays where its author put it; the contents beside it link to each section on GitHub.

OneShot

Important — Engineering discipline

Apply these rules when writing, editing, or proposing code.

  • Solve the accepted problem with the smallest complete change. Reuse existing mechanisms; preserve unrelated work. Validate external inputs and real failure states.
  • Read the affected implementation, callers, and shared utilities before editing. Ground code claims in inspected evidence.
  • Implement the general behavior. Tests must distinguish correct behavior from the defect; never hard-code to fixtures or preserve a demonstrably wrong test.
  • Carry scope, corrections, and existing authorization through handoffs. Run applicable required checks; repeat them only for changed behavior or unresolved failures.

Critical — Label hygiene

Remove private planning labels and process narration from shipped code and prose. State the domain behavior directly.

  • Planning labels — replace WS-N, Phase-A, Step-3, and private plan names with domain terms.
  • Process narration — remove authoring history and references that require private planning context. Explain the resulting behavior or constraint.

Keep useful issue links, public ticket identifiers, user-requested traceability, and labels where the artifact defines that format. Reviewer-facing migration docs may name deleted artifacts.

Important — Writing rules

Apply these rules to emitted prose: docs, comments, commit messages, PR bodies, and release notes.

  • Match surrounding punctuation, capitalization, and formatting.
  • Every sentence changes the reader's understanding. Cut it otherwise.
  • Lead with the action or outcome.
  • Use concrete language and lists when they improve comparison or sequence.
  • Assert positively. Reserve negation for real constraints (NEVER commit secrets).
  • No marketing words: powerful, robust, seamlessly, leverage, unlock, comprehensive, delightful.
  • No AI tells: delve, tapestry, intricate, pivotal, testament, underscore, crucial, garner, showcase, additionally, moreover, furthermore, indeed.
  • For substantive English prose, use /humanize-en if installed with the existing scope and authorization. It adds no approval stage; skip redundant passes over short status text.

Read the full file on GitHub · 146 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. yesterday Changed · -13 lines · -52 tokens per session 56117d89a4e9
  2. 9d ago First seen · 159 lines · 111 tokens per session scan A bee1a08950dc

Subscribe to this mod's changes

oneshot is a skill published in the GitHub repository coroboros/agent-skills (4 stars, last pushed 2d ago), licensed MIT. It adds 59 tokens to every session and 1,806 once invoked, about $0.0003 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.

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