CCAR-F Tool Design and MCP Integration Practice Question
Exhibit
{
"name": "get_system_metrics",
"description": "Fetches CPU usage",
"inputSchema": {
"type": "object",
"properties": {
"interval": {
"type": "string",
"description": "Time window in seconds"
}
},
"required": ["interval"]
}
}Refer to the exhibit. The model fails to return accurate data when the user asks for metrics over a 'five minute' interval. What is the most likely cause?
⚠ Common exam trap
Many candidates think the model can automatically deduce unit requirements like converting minutes to seconds without explicit schema instructions.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The inputSchema lacks explicit constraints or a more descriptive instruction for the argument.
The tool definition requires a string input but does not specify the expected unit or format (e.g., ISO8601 or seconds as an integer). Because the model cannot infer that 'five minutes' must be converted to '300' seconds, it passes the raw input, causing the backend to fail. Improving the schema with a description specifying unit requirements is essential for robust tool interaction.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The tool name 'get_system_metrics' is not unique enough to be invoked correctly.
Why it's wrong here
Tool invocation is based on the provided schema definition and name registration within the MCP session. While unique names are best practice, the issue here is semantic ambiguity in the input parameter, not the name of the tool function itself. The server would correctly receive the call regardless.
- ✓
The inputSchema lacks explicit constraints or a more descriptive instruction for the argument.
Why this is correct
The schema fails to define expected formats or units, leaving the model to guess how to map 'five minutes' to the string 'interval'. Adding explicit documentation or constraining the input to a numeric type would guide the model to provide the correctly formatted data the backend logic requires.
- ✗
The MCP server is missing a required 'outputSchema' field in the definition.
Why it's wrong here
MCP tool definitions primarily focus on the input interface for the model. While defining the output schema is helpful for structured logging and debugging, it is not a required component for the initial invocation. The failure described relates specifically to the handling of the input parameter provided.
- ✗
The model is unable to handle more than one argument for an MCP tool.
Why it's wrong here
Claude is fully capable of handling multiple arguments for MCP tools provided they are correctly defined in the input schema. The limitation observed here is not related to the number of arguments, but rather to the data format and semantic expectations of the specific parameter being passed.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Anthropic exam blueprint
This CCAR-F practice question is part of Courseiva's free Anthropic certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the CCAR-F exam.