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 skills add cognitedata/builder-skills --skill create-client-toolgit clone --depth 1 https://github.com/cognitedata/builder-skillsWrote 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/skills/cognitedata/builder-skills/create-client-tool)<a href="https://agentmods.dev/skills/cognitedata/builder-skills/create-client-tool"><img src="https://agentmods.dev/badge/skills/cognitedata/builder-skills/create-client-tool/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.
<a href="https://agentmods.dev/skills/cognitedata/builder-skills/create-client-tool"><img src="https://agentmods.dev/badge/skills/cognitedata/builder-skills/create-client-tool.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- Socket pass
- Snyk pass
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 5.1 | $0.00055 | $0.00964 |
| Opus 5.5 | $0.00022 | $0.00386 |
| Sonnet 5.5 | $0.00011 | $0.00193 |
| Haiku 4.5 | $0.00006 | $0.00096 |
Grade A, and why
create-client-tool 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 2mo 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.
How it starts
The opening of the file, as written. The whole thing — 109 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Create a Client Tool
Scaffold an AtlasTool named $ARGUMENTS. If the app has no approved in-app useAtlasChat, implement a Fusion action via integrate-fusion-agent instead.
Prerequisite: vendored src/atlas-agent/ and @sinclair/typebox from integrate-atlas-chat.
Background
Client tools let the Atlas Agent invoke browser-side logic — charts, local state, UI panels, navigation. The agent decides when to call; the app executes and returns a result.
- Agent responds with a
clientToolaction - TypeBox validates the arguments
execute()runs in the browser and returns{ output, details }output(string) is sent back to the agentdetailsis available onmessage.toolCallsfor the UI to render
Step 1 — Understand the codebase
Before writing anything, read:
- The file where
useAtlasChatis called (oftensrc/App.tsxor a chat hook) to find wheretoolsis passed — imports are typically from./atlas-agent/reactafterintegrate-atlas-chat - Any existing tool definitions to match the file/naming conventions
Step 2 — Define the tool
Use Type from @sinclair/typebox for the parameters schema (compile-time types + runtime validation).
import { Type } from "@sinclair/typebox";
import type { AtlasTool } from "./atlas-agent/types";
export const myTool: AtlasTool = {
name: "my_tool", // snake_case — this is what the agent uses to invoke it
description:
"One sentence describing what this tool does and when the agent should call it.",
parameters: Type.Object({
exampleParam: Type.String({ description: "What this param is for" }),
optionalNum: Type.Optional(Type.Number({ description: "..." })),
}),
execute: async (args) => {
return {
output: "Plain text summary sent back to the agent",
details: {
// Any structured data you want available in the UI via message.toolCalls
},
};
},
};
Adjust the ./atlas-agent/... path if the tool file is not directly under src/ next to the atlas-agent folder (for example ../atlas-agent/types from src/tools/).
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.
- 2mo ago Changed · -14 lines · -71 tokens per session 97feba94a9e0
- 2mo ago First seen · 123 lines · 126 tokens per session scan A cf49565a62d7
create-client-tool is a skill published in the GitHub repository cognitedata/builder-skills (6 stars, last pushed yesterday), licensed Apache-2.0. It adds 55 tokens to every session and 964 once invoked, about $0.0002 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 2026-08-31.
create-client-tool compared with skills from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| create-client-toolcognitedata/builder-skills | Skill | 6 | yesterday | Apache-2.0 | A | 55 | Claude Code |
| imagegenopenai/codex | Skill | 134k | today | Apache-2.0 | A | 113 | Codex |
| playwright-climicrosoft/playwright | Skill | 99k | today | Apache-2.0 | A | 19 | Claude Code |
| local-ai-agentsmicrosoft/ai-agents-for-beginners | Skill | 79k | today | MIT | A | 200 | Claude Code, Codex |
| systematic-debuggingobra/superpowers | Skill | 314k | 3d ago | MIT | A | 21 | Claude Code |
| next-cache-components-adoptionvercel/next.js | Skill | 143k | yesterday | MIT | A | 95 | Claude Code |
| next-partial-prefetching-adoptionvercel/next.js | Skill | 143k | yesterday | MIT | A | 103 | Claude Code |