prompt-eval

Evaluate system prompts for correct tool-calling behavior using mock tools and deterministic assertions.

Updated Aug 23, 2026
One-click install
npx skills add https://github.com/ElvinOuyang/claude-skill-collection --skill prompt-eval
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: prompt-eval
Source: https://github.com/ElvinOuyang/claude-skill-collection/tree/main/plugins/ai-dev-toolkit/skills/prompt-eval
Command: npx skills add https://github.com/ElvinOuyang/claude-skill-collection --skill prompt-eval

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill includes scripts (resource) components.

What problem does it solve?

Prompt-eval makes it possible to objectively test whether an AI system prompt triggers the correct tool calls with the correct parameters, without real side effects.

Core Features & Use Cases

  • Mock tool-call execution: Runs evaluation runs using a skill-packaged prompt plus a mock tool caller that logs tool invocations to a JSONL file.
  • Deterministic grading via assertions: Automatically checks expectations against tool-call logs (and optionally response text) using keyword-based matching.
  • Inline and model-comparison modes: Supports running evals in the current session (no extra API cost) or spawning subagent runs to compare models like Haiku vs Sonnet.
  • Use Case: Ensure a router or agent prompt correctly calls tools (e.g., task creation, reminders, or clarifications) across a set of behavioral test cases like happy paths, unknown inputs, and multi-step flows.

Quick Start

Ask the AI to package your target system prompt as a skill using a SKILL.md plus a scripts/call_tool.sh mock tool logger, then run the evals defined in evals/evals.json and grade them with grade_evals.py.

Frequently Asked Questions about prompt-eval

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I test if an AI system prompt triggers the correct tool calls?

You can test if a system prompt triggers correct tool calls by packaging it as a skill with a mock tool caller that logs invocations to a JSONL file, then running deterministic grading assertions against those logs to verify expected behavior.

Can I compare model performance for tool-calling prompts without real side effects?

Yes, you can compare model performance by spawning subagent runs to evaluate models like Haiku vs Sonnet, using mock tool-call execution to log invocations and grade behavior deterministically without real side effects.

What do I need to set up tool-calling prompt evaluations?

To set up tool-calling prompt evaluations, you need a root SKILL.md with tool-calling instructions, a scripts/call_tool.sh mock tool logger for JSONL output, an evals/evals.json test suite, and a grade_evals.py script to compare expected vs observed logs.

How do mock tool-call evaluations handle multi-step and edge-case agent scenarios?

Mock tool-call evaluations handle multi-step and edge-case scenarios by running a test suite of behavioral cases—including happy paths, unknown inputs, and multi-step flows—against the skill-packaged prompt to ensure correct task routing and tool invocation.

Does prompt testing for agent workflows support inline evaluation runs?

Yes, prompt testing for agent workflows supports inline evaluation runs within the current session to avoid extra API costs, as well as subagent runs for broader model comparison across varied user messages.

How are deterministic grading assertions applied to logged tool-call parameters?

Deterministic grading assertions are applied by automatically checking expectations against logged tool-call parameters and optionally response text, using keyword-based matching to compare expected vs observed tool-call logs.