CCDV-F Practice Test 12 — 15 Questions

Question 1

A developer is building a Claude-powered assistant that uses a tool called 'search_knowledge_base'. The tool definition includes a required parameter 'query' and an optional 'max_results' parameter. During testing, Claude sometimes calls the tool without providing 'max_results'. What should the developer do to ensure the tool call is handled correctly?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

In the tool implementation, check if 'max_results' is present and apply a sensible default value if it is missing.. Because 'max_results' is optional, Claude may omit it. The tool implementation should check for its presence and apply a default value, ensuring the tool works correctly regardless. This approach maintains the intended flexibility of the tool definition and prevents runtime errors. Other options either incorrectly change the tool contract or rely on unreliable prompting.

Answer

Add a description to the tool definition instructing Claude to always include 'max_results' with a value of 10.

Answer

Change the tool to accept a single string parameter that combines the query and max_results, such as 'query|max_results'.

Answer

Make 'max_results' a required parameter in the tool definition so Claude must always provide it.

Question 2

A developer is building an agent using the Anthropic Python SDK. The agent's system prompt instructs it to answer questions about a company's internal policies by searching a vector database. The developer wants the agent to autonomously decide when to search and when to answer directly. Which combination of API features should the developer implement to achieve this?

Accepted Answer

Define a tool that queries the vector database, include it in the `tools` parameter of the Messages API request, and handle `tool_use` blocks in the response by executing the search and returning a `tool_result` block.. The correct approach is to define the vector search as a tool, include it in the request, and handle the tool_use/tool_result cycle. This enables the model to decide when to search based on the conversation, which is the core of agentic behavior with the Anthropic SDK. Other options either force tool use, embed excessive context, or bypass the model's decision-making entirely.

Answer

Use the `system` parameter to embed the entire vector database content as context, allowing the model to answer directly without tool use.

Answer

Implement a pre-processing step that always queries the vector database and appends the top result to the user's message before sending it to the model.

Answer

Set the `tool_choice` parameter to `{"type": "any"}` so the model always calls the vector search tool, and then parse the result to generate the final answer.

Question 3

A developer is building a customer-support bot with the Claude Messages API. The system prompt instructs Claude to answer concisely, but the bot also needs to return a stable JSON object with the fields 'intent', 'sentiment', and 'reply' on every turn. Where should the instruction to produce this JSON object be placed to most reliably control the response format?

Accepted Answer

In the system prompt, placed after the conciseness instruction.. The system prompt is the correct place because it is sent with every Messages API request and reliably conditions all assistant turns. Interface requirements such as JSON keys should live there so they are not diluted by user content. Putting format rules in the user turn or in a lone assistant example makes them fragile and easy to override.

Answer

Only in the first assistant message as an example.

Answer

Appended to each user message as a trailing reminder.

Answer

In a separate follow-up call after Claude replies in prose.

Question 4

An agent built with the Claude Agent SDK runs a long research task and repeatedly hits the model's context window limit. The developer wants the agent to keep working without losing critical earlier findings. Which approach best addresses this?

Accepted Answer

Enable automatic context compaction so older turns are summarized into a condensed form while key findings are retained in the running context.. Long-running agents need a strategy for the finite context window. Compaction condenses older turns into summaries or retained highlights, freeing tokens while keeping the findings the agent depends on. Sampling parameters and response-length caps do not reclaim history, and restarting loses state, so compaction is the mechanism that lets the run continue coherently.

Answer

Raise the temperature so the model generates shorter responses and consumes fewer tokens per turn.

Answer

Restart the agent from scratch each time the limit is reached, relying on the model to re-derive earlier findings from the task prompt.

Answer

Increase the model's max_tokens parameter so each response can be longer and the context window is used more efficiently.

Question 5

A developer is writing a tool called `send_email` for a Claude-based assistant. The tool's description currently reads: 'Sends an email.' During testing, Claude calls the tool for tasks like drafting an email or checking inbox contents. Which revision to the tool definition most directly improves Claude's decision about when to invoke `send_email`?

Accepted Answer

Rewrite the description to state precisely what the tool does, when to use it, and when not to use it, such as only when the user explicitly asks to send a message.. The model chooses tools primarily from their descriptions, so a vague one like 'Sends an email' invites calls for drafting or inbox checks. A description that states the exact action, the conditions that should trigger it, and explicit non-triggers such as drafting or retrieving messages gives Claude the criteria it needs. Schema changes and renaming affect argument validity or naming, not the decision of when the tool applies.

Answer

Set `input_schema` to `type: "object"` with `additionalProperties: false` to lock down the parameter set.

Answer

Rename the tool from `send_email` to `email` and rely on the shorter name to signal its broader role.

Answer

Add a `required` array listing `to`, `subject`, and `body` in the input schema.

Question 6

A developer is tuning a customer-feedback classifier on the Anthropic API. The model currently mislabels sarcastic complaints as praise. The developer wants to improve accuracy using few-shot examples in the prompt. Which TWO practices should be applied? (Choose two.)

Accepted Answer

Include examples that cover the difficult sarcastic cases alongside typical positive and negative examples.. Effective few-shot prompting targets the observed failure mode with representative, correctly labeled edge cases, and structures each example so the input-to-label mapping is unambiguous. Covering sarcastic cases fixes the specific boundary error, while delimiter tags prevent confusion between example text and labels. Volume, repetition, and post-target placement do not broaden the decision boundary and can introduce new biases.

Answer

Use the same example repeatedly so the model strongly memorizes the sarcasm pattern.

Answer

Place all examples after the user's feedback text so the model reads the target first.

Answer

Provide as many examples as the context window allows, prioritizing quantity over diversity.

Question 7

A developer is using Claude Code to refactor a function across multiple files. After a few edits, Claude Code proposes a change that would alter the behavior of a critical utility function used elsewhere. The developer wants to ensure the change is safe before applying it. What is the most appropriate action?

Accepted Answer

Reject the change and ask Claude Code to propose an alternative that preserves the existing behavior.. Rejecting the proposed change and asking for an alternative that preserves existing behavior is the safest approach when a critical utility function is involved. It keeps the developer in control and avoids unintended side effects. Other options either apply the risky change, discard too much work, or bypass the review process entirely.

Answer

Use the `/undo` command to revert all previous edits and start the refactor from scratch.

Answer

Accept the change and run the full test suite afterward to catch any regressions.

Answer

Manually edit the utility function to match the proposed change and then continue.

Question 8

A developer is building a customer support agent using the Anthropic SDK. The agent must call a 'get_order_status' tool that requires an order ID. During testing, the agent sometimes invents plausible-looking order IDs instead of asking the user. Which change to the tool definition will most directly reduce this behavior?

Accepted Answer

Add a detailed 'description' field to the tool that explains when to use it and explicitly instructs the model not to guess missing parameters.. The tool description is the model's instruction manual for when and how to invoke a tool. By explicitly stating that the agent must request an order ID from the user rather than guessing, the developer directly targets the observed hallucination. Schema changes, token limits, and renaming do not convey that behavioral rule.

Answer

Increase the 'max_tokens' setting so the model has more room to reason before emitting the tool_use block.

Answer

Set 'input_schema' to an empty object so the model is forced to ask the user for all parameters.

Answer

Change the tool name to 'lookup_order' so it sounds more like a retrieval operation.

Question 9

A developer is using the Messages API to have Claude return a JSON object describing a product. The response sometimes includes a conversational preamble such as 'Here is the JSON you requested:' before the object, which breaks the downstream parser. What is the most reliable way to eliminate the preamble?

Accepted Answer

Use the assistant turn prefill with an opening curly brace so the response must continue from that character.. Prefilling the assistant turn with an opening brace removes the space where a preamble could be generated, forcing the response to begin mid-JSON. Instructions and temperature settings only bias behavior probabilistically, and token limits address length rather than structure. Prefill is the only option that structurally guarantees the response starts with the expected character.

Answer

Increase max_tokens so the model has enough room to output the full JSON without truncation.

Answer

Set the temperature to zero so the model always produces the same output.

Answer

Add 'Do not include any preamble' to the system prompt and hope the model complies.

Question 10

You are building a summarization feature that processes 20,000 support tickets nightly. Each ticket is under 4,000 tokens and the output summary is around 300 tokens. The job must complete within a 6-hour window and you want to minimize cost. Which Claude model should you choose?

Accepted Answer

Claude 3 Haiku. For high-volume, short-input summarization where cost is the primary constraint, Claude 3 Haiku provides the best balance of speed, quality, and price. Its lower per-token cost directly reduces the total spend for 20,000 requests, and its speed helps meet the 6-hour window. More expensive models like Sonnet or Opus are overkill for this task.

Answer

Claude 3 Sonnet

Answer

Claude 3 Opus

Answer

Claude 3.5 Sonnet

Question 11

A developer is building a Claude-powered assistant that uses a tool called 'search_knowledge_base'. The tool definition includes a required parameter 'query' and an optional 'max_results' parameter. During testing, Claude sometimes calls the tool without providing 'max_results'. What should the developer do to ensure the tool call is handled correctly?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Enable Prompt Caching on the codebase context so subsequent requests reuse the cached prefix at a reduced input token rate.. Prompt Caching is designed exactly for repeated large static prefixes such as a codebase that changes infrequently. Cache reads are billed at a lower rate than standard input tokens, and the cache persists for a short TTL, so a weekly update cadence yields very high hit rates. The other approaches either discard necessary context or rely on unsupported mechanisms.

Answer

Use the smallest available model and hope it can reason about the codebase without additional context.

Answer

Send only the file names and ask Claude to infer the implementation details from the names.

Answer

Compress the codebase using a custom tokenizer before sending it to the Messages API.

Question 12

A developer is building an application that uses the Claude Messages API to generate product descriptions. The application sends a system prompt of 1,500 tokens, a user prompt of 200 tokens, and receives a response of 300 tokens. The developer wants to reduce costs. Which two strategies would directly reduce the cost per API call? (Choose two.)

Accepted Answer

Use a smaller model like Claude 3 Haiku instead of Claude 3 Opus.. The cost per API call is determined by the number of input and output tokens and the model's pricing. Shortening the system prompt reduces input tokens, and using a smaller model like Claude 3 Haiku lowers the per-token cost. Both directly decrease the cost of each call. Increasing max_tokens, enabling streaming, or caching responses do not reduce the token-based cost of an individual call.

Answer

Enable streaming to receive tokens as they are generated.

Answer

Increase the max_tokens parameter to allow longer responses.

Answer

Cache the model's responses for identical prompts.

Question 13

A team wants Claude Code to run a custom script that inspects the repository for license headers before any commit. The script must run automatically each time Claude Code is about to create a commit, and the team wants the same hook to apply to every developer without manual setup. Which mechanism should they use?

Accepted Answer

Define a hook in the project's Claude Code settings that triggers on the commit event and runs the script.. Hooks defined in project-level Claude Code settings run deterministically on lifecycle events such as pre-commit and are shared through the repository, so every developer gets identical behavior automatically. Advisory notes in CLAUDE.md and per-machine aliases or cron jobs are either non-enforcing or require individual setup, and none reliably fires at the exact moment Claude Code is about to commit.

Answer

Ask each developer to add the script to their personal shell profile as an alias.

Answer

Configure a cron job on each developer machine to run the script every five minutes.

Answer

Add a note in CLAUDE.md instructing Claude Code to run the script before committing.

Question 14

A developer is streaming a response from the Anthropic Messages API using server-sent events and wants to assemble the final text on the client. They observe that each event delivers a small fragment of the answer. Which event type carries the incremental text delta that must be concatenated to reconstruct the full completion?

Accepted Answer

content_block_delta. Streaming responses arrive as a sequence of typed server-sent events, and the actual generated text is delivered piecewise inside content_block_delta events. A client must concatenate those deltas in order and treat message_start, content_block_stop, message_delta, and message_stop as structural markers rather than content.

Answer

content_block_stop

Answer

message_start

Answer

ping

Question 15

A developer is integrating a new MCP server that exposes a company's internal HR policy documents. The server implements the Resources capability. The developer wants Claude to access a specific policy document only when the user explicitly asks about it, rather than loading all documents into context upfront. Which MCP method should the developer use to retrieve the content of a single resource by its URI?

Accepted Answer

resources/read. The correct method is resources/read because it retrieves the content of a specific resource by URI, which matches the need to fetch a single HR policy document on demand. Other resource-related methods like list, subscribe, or templates/list provide metadata or notifications, not the actual document body. Using resources/read avoids preloading all documents into context and keeps the interaction efficient.

Answer

resources/list

Answer

resources/templates/list

Answer

resources/subscribe