The answer is that the parameter name is incorrect, as the AI21 Labs Jurassic-2 Mid model expects 'maxTokens' with a capital T. This is because Amazon Bedrock’s InvokeModel API passes parameters directly to the underlying model, and the Jurassic-2 model schema strictly requires camelCase parameter names. When you encounter an InvokeModel API error like "unsupported maxTokens parameter for Jurassic-2 model," it almost always means you used a different casing—such as 'maxtokens' or 'max_tokens'—which the model does not recognize. On the AWS Certified AI Practitioner AIF-C01 exam, this question tests your understanding that Bedrock acts as a pass-through to each model’s unique API, and the common trap is assuming all models accept the same parameter format. A helpful memory tip: think of the capital T in "maxTokens" as standing for "Titan" or "Token"—it’s the only way Jurassic-2 will accept it.
AIF-C01 Applications of Foundation Models Practice Question
This AIF-C01 practice question tests your understanding of applications of foundation models. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Exhibit
Refer to the exhibit.
error: text generation failed with status code 400
{
"error": {
"message": "The model 'ai21.j2-mid-v1' does not support the 'maxTokens' parameter. Use 'maxTokens' with supported models or remove it.",
"type": "invalid_request_error"
}
}
A developer is calling the Amazon Bedrock InvokeModel API to generate text with the AI21 Labs Jurassic-2 Mid model. The API call includes a maxTokens parameter, but the request fails with the error shown in the exhibit. What is the most likely cause of this error?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Refer to the exhibit.
error: text generation failed with status code 400
{
"error": {
"message": "The model 'ai21.j2-mid-v1' does not support the 'maxTokens' parameter. Use 'maxTokens' with supported models or remove it.",
"type": "invalid_request_error"
}
}
A
The API request is missing a required parameter such as 'prompt'.
Why wrong: The error specifically mentions the 'maxTokens' parameter, not a missing required parameter.
B
The AWS region does not support the AI21 Labs model.
Why wrong: The error is a client-side 400 error, not a regional availability issue.
C
The value of 'maxTokens' exceeds the model's maximum limit.
Why wrong: The error states the parameter is not supported, not that the value is out of range.
D
The parameter name is incorrect; the model expects 'maxTokens' with a capital T.
Jurassic-2 Mid uses 'maxTokens' (capital T) as the parameter name for controlling output length.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The parameter name is incorrect; the model expects 'maxTokens' with a capital T.
The AI21 Labs Jurassic-2 Mid model expects the parameter name 'maxTokens' with a capital 'T' (camelCase). The error occurs because the API request used a different casing (e.g., 'maxtokens' or 'max_tokens'), which the model's schema does not recognize. Amazon Bedrock's InvokeModel API passes parameters directly to the model, so parameter names must match the model's exact specification.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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 API request is missing a required parameter such as 'prompt'.
Why it's wrong here
The error specifically mentions the 'maxTokens' parameter, not a missing required parameter.
✗
The AWS region does not support the AI21 Labs model.
Why it's wrong here
The error is a client-side 400 error, not a regional availability issue.
✗
The value of 'maxTokens' exceeds the model's maximum limit.
Why it's wrong here
The error states the parameter is not supported, not that the value is out of range.
✓
The parameter name is incorrect; the model expects 'maxTokens' with a capital T.
Why this is correct
Jurassic-2 Mid uses 'maxTokens' (capital T) as the parameter name for controlling output length.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the nuance that model-specific parameter names must match exactly, including case sensitivity, and candidates mistakenly assume all Bedrock models use the same parameter naming convention.
Detailed technical explanation
How to think about this question
Under the hood, Amazon Bedrock's InvokeModel API acts as a pass-through to the underlying model provider's inference endpoint. Each model (e.g., AI21 Labs Jurassic-2 Mid) defines its own JSON schema for request parameters, including exact casing for fields like 'maxTokens'. If the casing does not match, the model's schema validation fails with a 'ValidationException' or 'MalformedRequestException', not a value-related error. In real-world scenarios, developers often confuse camelCase (e.g., 'maxTokens') with snake_case (e.g., 'max_tokens') used by other providers like Anthropic or Cohere.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Applications of Foundation Models — This question tests Applications of Foundation Models — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The parameter name is incorrect; the model expects 'maxTokens' with a capital T. — The AI21 Labs Jurassic-2 Mid model expects the parameter name 'maxTokens' with a capital 'T' (camelCase). The error occurs because the API request used a different casing (e.g., 'maxtokens' or 'max_tokens'), which the model's schema does not recognize. Amazon Bedrock's InvokeModel API passes parameters directly to the model, so parameter names must match the model's exact specification.
What should I do if I get this AIF-C01 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
This AIF-C01 practice question is part of Courseiva's free Amazon Web Services 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 AIF-C01 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.