pet-tools-mcp

by nschneir

Overview Schema Source Related Servers Discussions Admin

Python

Local

pet_step

Execute a specified number of CPU instructions in a Commodore PET emulator session, then stop for inspection.

Instructions

Execute N instructions. The machine STAYS STOPPED afterwards; use pet_continue to resume.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "pet_step"
  }
}

Input Schema

Name	Required	Description	Default
`over`	No
`count`	No
`session`	No

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Jul 11, 2026

TDQS

A3.5/5.0

Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Given no annotations, the description adds some behavioral context: 'The machine STAYS STOPPED afterwards'. This informs the agent about the tool's action effect. However, it does not disclose potential destructive nature, session requirements, or other traits that would be expected with a 0% annotation coverage.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is concise with two sentences. It is front-loaded with the action and includes a key behavioral note, with no wasted words.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the lack of output schema and 0% parameter coverage, the description is significantly incomplete. It does not explain parameters or return values, leaving major gaps for an agent to correctly invoke the tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters1/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The description provides no explanation for the three parameters ('over', 'count', 'session'). With 0% schema coverage, the description should compensate, but it fails entirely, leaving the agent without guidance on parameter usage.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action ('Execute N instructions') and the resource ('instructions'). It distinguishes from the sibling 'pet_continue' by noting that the machine stays stopped and instructs to use 'pet_continue' to resume.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description explicitly says the machine stays stopped and to use 'pet_continue' to resume, providing clear context for when to use this tool versus an alternative. However, it does not address other siblings like 'pet_run' or 'pet_until'.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.