CCDV-F flashcards.

47 cards for the Claude Certified Developer – Foundations exam, grouped by domain in the blueprint’s order of weight. Each one is distilled from a question in our free practice bank. Open a card to see the answer.

Applications and integration 33.1%

What does stop_reason max_tokens mean?

The output hit the max_tokens cap you set and was cut off. Raise the limit or continue the response.

What does stop_reason end_turn mean?

The model finished its turn naturally and is not waiting on anything.

What must your code do after stop_reason tool_use?

Run the requested tool, send its output in a tool_result block with the matching id, and call the model again. Client tools are not run on the server.

What does stop_reason stop_sequence mean?

The output reached one of the custom stop sequences you set.

Which fields does every Messages API request need?

model, messages and max_tokens. system, temperature and stream are optional.

Where does the system prompt go in a Messages API request?

In the top-level system parameter. The messages array only takes user and assistant roles.

How do you show a response as it is generated?

Set stream to true and render content_block_delta events as they arrive. A complete stream ends with message_stop.

How do you send an image to Claude?

As an image content block in a user message, with a source of type base64 or url.

When should you use the Message Batches API?

For large workloads with no latency requirement, at lower cost. Read each request's result separately: a batch is not atomic.

How does prompt caching cut the cost of a repeated prompt?

A cache_control breakpoint after a stable prefix, such as a long manual or system prompt, lets later requests read that prefix from cache.

What is the Files API for?

Uploading a document once and referencing it by file id across requests. Referenced files still count as input tokens.

What should a client do on HTTP 429?

Back off exponentially with jitter and honor the retry-after header. Limits apply per organization, so switching keys does not help.

What usually causes HTTP 400 invalid_request_error?

A malformed request, such as a missing required field or an unsupported parameter. Rate limits are 429, permissions 403 and overload 529.

Which header carries your API key?

x-api-key. anthropic-version is a separate required header that pins the API version.

How do you count tokens before sending a large prompt?

Call the token counting endpoint, which returns the input tokens for the prompt.

What is the most reliable way to get structured output?

Define a tool with a JSON schema for the fields, force it with tool_choice, and validate the arguments that come back.

Model selection and optimization 16.8%

How should you choose a model tier for a new feature?

Prototype on a capable tier, then test whether a smaller tier passes your eval at lower cost.

Which tier suits simple, high-volume extraction?

The smallest tier that passes your eval, because cost and latency dominate at that volume.

Which setting makes output more deterministic?

A temperature near 0. Caching reuses computation but does not constrain sampling.

What does max_tokens control?

The maximum number of output tokens. Input is bounded separately by the model's context window.

How do you cut latency when output tokens dominate it?

Constrain the output's length and format so the model writes fewer tokens.

When is extended thinking worth its cost?

On hard multi-step problems where accuracy matters more than latency. Thinking tokens are billed as output on every request.

How should you compare two models for your task?

Run the same eval set through both and compare accuracy, cost and latency.

Agents and workflows 14.7%

What is the agent loop?

Call the model; on tool_use run the tool, append the result and call again; stop on end_turn or a turn cap.

What must happen after a tool call, before calling the model again?

Append a tool_result block whose tool_use_id matches the tool_use block, which stays in the history.

What does the Claude Agent SDK handle for you?

The agent loop, tool execution, permission checks, hooks and subagents.

What should limit an agent loop besides end_turn?

A maximum number of iterations, plus a time or cost budget.

What are Agent SDK hooks for?

Deterministic checks around tool calls, such as blocking a dangerous command.

How do subagents work in the Agent SDK?

They run in their own context and return a result to the parent, not their transcript.

What is the evaluator-optimizer pattern?

One call generates, a second grades the result, and the work is revised until it passes.

How should code model a step that needs human input?

As a durable pause that saves progress and resumes when the input arrives.

Prompt and context engineering 11%

Where should a long reference document go in a prompt?

Before the question, clearly delimited: documents first, question last.

How do you keep instructions inside a document from being followed?

Wrap the document in tags, label it as data, and keep your instructions outside it.

What do you do when conversation history outgrows the context window?

Summarize older turns and keep recent turns verbatim. A summary keeps decisions and state that truncation would drop.

How do you make an extraction prompt more reliable without changing the model?

Add examples of input and expected output, including an edge case.

Tools and MCPs 10.6%

How do you restrict a tool parameter to a few fixed values?

Use an enum in the parameter's JSON schema and list the parameter as required.

What does a tool_result with is_error set to true tell the model?

The call failed and the content says why, so the model can adapt. The API does not retry client tools.

What does tool_choice any do?

Requires the model to call some tool this turn without naming which. auto lets it decide; type tool names one.

What makes a good tool description?

It says what the tool does, when to use it, what it returns and how it fails.

What must a client handle when it connects to an MCP server over streamable HTTP?

Sessions and authentication for the remote server. Spawning a subprocess is the stdio transport.

Security and safety 8.1%

What protects an agent from prompt injection in pages it reads?

Treat retrieved content as data, keep instructions in the system prompt, and put approval gates on actions that send or delete.

What is least privilege for a shell tool?

A reviewed list of read-only commands, with approval required for anything that writes.

What is the first response to an API key committed to a public repository?

Rotate the key, remove it from the code, then audit recent usage.

What should change when personal data shows up in your logs?

Redact or minimize it, and set a retention policy.

Claude Code 3.1%

Which file gives Claude Code standing instructions for a repository?

CLAUDE.md, at the repository root or in .claude. settings.json holds permissions and configuration.

How do you run Claude Code for one non-interactive prompt?

claude -p with the prompt as an argument (print mode).

Eval, testing, and debugging 2.6%

How do you check a prompt change for regressions before shipping?

Run a golden test set with automated grading and compare the scores with the old prompt.

Keep going

Test the same material under exam conditions with the free timed CCDV-F practice exam, drill domain by domain with the CCDV-F practice questions, or read the CCDV-F exam guide and a four-week CCDV-F plan built on the blueprint.

Who wrote this

Matei Olaru

Matei Olaru

CEO, Your AI Department

Former public-company CEO, corporate attorney, and World Bank consultant. Runs the YAID Network and the partner relationship with Anthropic.

Michael Greenberg

Michael Greenberg

AI Product Lead, Your AI Department

AI at Google, Meta, and Samsung. Six patents. Leads member support and the certification prep guidance.

Claude Partner NetworkYour AI Department is a registered Claude Partner Network company. Our members sit these exams under our partner standing. Facts on this page were last checked on October 15, 2026.