CPES - Exam Strategy¶

The Specialist exam tests judgment more than recall. Many questions show two prompt variants and ask which is better, or show a failing prompt and ask which intervention would help most. Your job is to recognize the technique each option represents and judge its fit.

3-Phase Preparation¶

Phase 1 - Read (Week 1)¶

Read Anthropic's prompt engineering guide twice. Make a one-page cheat sheet of techniques with examples. The exam vocabulary tracks the docs precisely.

Phase 2 - Practice (Weeks 2-3)¶

Iterate on a real task with measured evals. You should ship at least 5 prompt versions and know which technique drove which improvement.

Phase 3 - Drill (Week 4)¶

Run timed scenarios. Re-read the fact sheet. Sleep before the exam.

Time Management¶

Assume 55 questions in 90 minutes. ~1m 35s per question with a small buffer.

First pass: answer fast, flag the slow ones. Second pass: spend buffer on flags.

Reading Prompt Snippets Fast¶

Train yourself to spot:

• XML tag usage and consistency
• Where the question is placed (top, middle, bottom)
• Whether examples are in the prompt
• Whether the system field is used at all
• Whether cache_control appears
• Whether tool_choice is forced for structured output
• Whether prefill is used

Most "what is the best prompt" questions test one of these axes. Identify the axis first.

Common Question Patterns¶

"Which prompt is more effective?"¶

Look for:

• Better use of XML structure
• Explicit format and constraint specification
• Examples present and well-chosen
• Question position (top + bottom for long context)
• System prompt used appropriately

"What is the most effective change?"¶

Identify the failure mode the prompt currently exhibits, then match the intervention:

• Wrong format -> examples or forced tool choice
• Wrong tone -> system prompt with persona
• Bad reasoning -> chain of thought or extended thinking
• Verbose -> length constraint
• Lost in long context -> question at top and bottom; XML tags
• Inconsistent across calls -> few-shot anchoring
• Refuses inappropriately -> rephrase task; system prompt clarification

"Why is this prompt failing?"¶

Look for ambiguity, missing format spec, missing examples, dynamic content in cached regions, role prompts used as safety controls.

Answer Selection Heuristics¶

• Prefer documented Anthropic patterns over clever alternatives
• Prefer the simpler intervention that addresses the named failure
• Prefer techniques that compose (XML + examples + CoT) when the question allows
• Prefer extended thinking over prompt-level CoT when the model supports it AND you do not need visible reasoning
• Prefer forced tool choice for strict structured outputs
• Prefer examples over instructions for format requirements

Domain-Specific Tactics¶

Prompt Fundamentals¶

Look for clarity, specificity, and ordering. The best prompt is usually the most explicit one within reason.

System Prompts¶

System prompts persist; user prompts vary. Constraints and persona belong in system. The actual task belongs in user.

Chain of Thought¶

Three flavors: implicit ("think step by step"), structured (numbered steps), tagged (<thinking>/<answer>). All work; tagged is most parseable.

XML Tags¶

Use them. Be consistent. Tag names should be meaningful for the domain.

Few-Shot¶

Quality of examples beats quantity. Diversity beats redundancy. Include edge cases.

Evaluation¶

Eval datasets must have gold or rubric. LLM judges must be calibrated. A/B test deliberately.

Prompt Caching¶

cache_control on content blocks. Static content first. Dynamic content last. Verify with usage fields.

Counter-Intuitive Facts to Internalize¶

• Adding "be helpful and concise" alone often does little. Specify tokens or sentences.
• Long instructions can outperform short ones on hard tasks.
• Few-shot helps even when the task is well-described.
• Extended thinking can underperform a well-crafted prompt with no thinking on simple tasks (cost without benefit).
• Prefill is one of the most underused techniques.
• Roles do not bypass refusals.

The 24 Hours Before¶

• Re-read fact sheet
• Re-read this strategy
• Sleep
• Have ID and stable internet ready

During the Exam¶

• Read every prompt snippet fully; do not skim
• Identify the technique axis the question targets
• Eliminate two answers fast
• Choose the answer most aligned with Anthropic's documented patterns

If You Fail¶

Score reports show your weakest domain. Spend two weeks rebuilding it with hands-on exercises. Re-sit. Specialist exams reward depth in the craft, which compounds with practice.