pet-tools-mcp

by nschneir

Overview Schema Source Related Servers Discussions Admin

Python

Local

pet_break_add

Add a breakpoint at an address or symbol. The emulator keeps running; use pet_wait_break to block until it fires.

Instructions

Set a breakpoint at an address or symbol. Machine keeps running; use pet_wait_break to block until it fires.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "ref": "<ref>"
    },
    "name": "pet_break_add"
  }
}

Input Schema

Name	Required	Description	Default
`ref`	Yes
`session`	No
`condition`	No
`temporary`	No

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Jul 11, 2026

TDQS

A3.9/5.0

Behavior4/5

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It states that the machine keeps running (non-blocking), which is a key behavior. It does not detail side effects, but for a simple breakpoint add, the description is sufficiently transparent.

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 extremely concise at two sentences with no fluff. It front-loads the core purpose and immediately follows with the crucial behavioral note and alternative tool reference.

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 4 parameters, no output schema, and no annotations, the description is incomplete. It does not cover the return value or explain the optional parameters (session, condition, temporary), which are important for effective use of 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 input schema has 4 parameters with 0% description coverage, yet the tool description only hints at the 'ref' parameter ('at an address or symbol'). It provides no explanation for 'session', 'condition', or 'temporary', leaving the agent without semantic guidance beyond parameter names.

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 'Set a breakpoint at an address or symbol', providing a specific verb and resource. It further distinguishes itself from the sibling tool 'pet_wait_break' by noting that the machine keeps running, so the user knows this tool only sets the breakpoint without blocking.

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

Usage Guidelines5/5

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

The description explicitly tells the user to use 'pet_wait_break' to block until the breakpoint fires, giving clear guidance on when to use this tool versus an alternative. It implies that for non-blocking breakpoint addition, this is the correct choice.

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