# tool-design

> Claude/Codex skill by [@muratcankoylan](https://omgskills.com/library/muratcankoylan/index.md) · 18k stars · Updated 2026-10-12

This skill should be used for the tool-interface layer of an agent system specifically: writing tool descriptions agents can route on, designing tool schemas and response formats, naming conventions, actionable error recovery messages, MCP server design, tool-set consolidation, and deciding when to add or remove an individual tool. Use this when the unit of work is a single tool or a set of tools. Route project-shape, pipeline architecture, and task-model-fit decisions to project-development; route deciding whether to introduce sub-agents to multi-agent-patterns.

## Install

```sh
git clone https://github.com/muratcankoylan/Agent-Skills-for-Context-Engineering /tmp/Agent-Skills-for-Context-Engineering && ln -s /tmp/Agent-Skills-for-Context-Engineering/skills/tool-design ~/.claude/skills/tool-design
```

## From README

Tool Design for Agents Design every tool as a contract between a deterministic system and a non-deterministic agent. Unlike human-facing APIs, agent-facing tools must make the contract unambiguous through the description alone: agents infer intent from descriptions and generate calls that must match expected formats. Every ambiguity becomes a potential failure mode that no amount of prompt engineering can fix. The unit of work for this skill is a single tool or a tool catalog. Project-shape, pipeline architecture, task-model-fit, and cost-at-the-project-level decisions belong to project-development. Deciding whether to introduce sub-agents belongs to multi-agent-patterns. This skill owns the interface layer that connects deterministic code to the agent. When to Activate Activate this skill when the unit of work is a tool: Writing a new tool description, schema, or response format. Debugging cases where the agent picked the wrong tool or generated malformed calls.

## Links

- HTML page: https://omgskills.com/library/muratcankoylan/agent-skills-for-context-engineering/skills/tool-design/
- GitHub: https://github.com/muratcankoylan/Agent-Skills-for-Context-Engineering
- Author: [@muratcankoylan](https://omgskills.com/library/muratcankoylan/index.md)

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