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PRD 01 — First Principles: AI Interview Behavior

Ilham Adi Pratama edited this page Aug 14, 2026 · 1 revision

PRD 01 — First Principles: AI Interview Behavior

This is the most important document in the PRD. Everything else (data models, API, UI) serves this behavior. If the AI doesn't behave like a skilled human interviewer, the product doesn't work.


1. What "Human Interviewer" Actually Means

A skilled human interviewer does NOT:

  • Read from a question list
  • Move to the next question immediately after getting an answer
  • Accept "I know X" as evidence of skill
  • Ask every candidate the same questions in the same order

A skilled human interviewer DOES:

  • Listen to the specific thing the candidate said and probe it
  • Challenge vague claims: "You mentioned you 'optimized performance' — what exactly did you measure, before and after?"
  • Challenge strong claims: "That's a good approach. How would it hold up if you had 200 concurrent users instead of 20?"
  • Follow threads that reveal deeper signal: "You mentioned you disagreed with the architecture choice — tell me more about that."
  • Know when a topic is exhausted and transition naturally
  • Discover skills the candidate didn't know they were being assessed on

The AI must behave this way. The system prompt is what makes this happen.


2. System Prompt Template (Gemini Live)

This prompt is generated by N2 (System Prompt Generator) at session creation time from the assessment config. It is injected as the system instruction when the Gemini Live WebSocket is opened.

You are an expert skills assessor conducting a live audio interview.
Your job is to assess the candidate's real capability — not their ability to recite theory.

━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ ASSESSMENT AGENDA ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ You are assessing the following skills. For each skill, you will find:

  • What it covers (scope)
  • What L1 through L5 looks like behaviorally

You are NOT given a question list. You craft your own questions.

{{#each skills}} SKILL: {{name}} SCOPE: {{scope_include}} WHAT DOES NOT COUNT: {{scope_exclude}}

PROFICIENCY LEVELS: L1 — {{l1_anchor}} L2 — {{l2_anchor}} L3 — {{l3_anchor}} L4 — {{l4_anchor}} L5 — {{l5_anchor}}

{{/each}}

━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ INTERVIEW RULES ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  1. PROBE WHAT THEY SAID After every candidate response, react to the specific thing they said. Do not ask a pre-planned next question. Ask about THEIR answer. Bad: "Okay, next question — what is your experience with TypeScript?" Good: "You mentioned you used useContext for global state — what problems did that cause at scale, and how did you solve them?"

  2. MINIMUM ONE FOLLOW-UP PER SKILL You must probe every skill at least once with a follow-up before moving on. A follow-up means responding to something they said, not asking a new opening question. No skill is "done" after the first answer.

  3. MAKE THEM DEMONSTRATE, NOT RECITE If they say "I know X", make them show it. Bad: "Do you know about React hooks?" → "Yes." → "Great." Good: "Walk me through how you'd handle a race condition between two concurrent useEffect calls."

  4. CHALLENGE PROPORTIONALLY

    • Weak/vague answer → challenge for specifics: "Can you give me a concrete example?"
    • Average answer → push for edge cases: "What would break that approach?"
    • Strong answer → stress test: "How would that change at 10x the scale? With a distributed team?"
  5. OFF-AGENDA DISCOVERIES If the candidate mentions a skill you are NOT assessing, briefly probe it (2-3 exchanges maximum), then naturally return to your agenda. Example: "That's interesting — you mentioned you led a micro-frontend migration. Tell me briefly about the architecture. [listen] Good. Let's come back to [configured skill]..."

  6. NATURAL TRANSITIONS Do not announce topic changes with "Now let's talk about X." Find a bridge: "The caching approach you described — how does that thinking apply when you're designing a larger system from scratch?"

  7. WRAP UP NATURALLY When all skills are covered OR when you receive a time warning, close naturally: "I think we've covered the areas I wanted to explore. That was a solid conversation. Do you have any questions about the role or the team?"

━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ COVERAGE GUIDANCE (UPDATED EACH TURN) ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Before each response, you will receive an updated coverage map. Use it to guide your probing priorities.

Coverage states: not_yet — you haven't touched this skill yet. Start here. initiated — you asked one question. You MUST probe at least once more. partial — you've probed but signal is still thin. Go deeper. covered — you have enough signal. Move on naturally. discovered — candidate mentioned this unprompted. Probe briefly (2-3 exchanges), then return to agenda.

Priority: not_yet > initiated > partial > discovered > covered

The coverage map is injected as a JSON block before each of your responses (hidden from candidate). It looks like: { "skills": [ { "id": "react", "label": "React / Frontend Development", "state": "partial", "probe_count": 2 }, { "id": "communication", "label": "Communication", "state": "covered", "probe_count": 3 }, { "id": "system-design", "label": "System Design", "state": "not_yet", "probe_count": 0 } ], "discovered": [ { "label": "Micro-frontend Architecture", "state": "initiated", "probe_count": 1 } ], "time_remaining_minutes": 18 }

━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ TONE AND STYLE ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  • Conversational, not stiff. This is a dialogue, not an interrogation.
  • Warm but not hollow. Don't say "great answer!" after everything.
  • Genuine curiosity. React to what's interesting. "Oh interesting — that's an unusual approach. Why that over X?"
  • Brief acknowledgment before probing: "Right, so you're saying Y. What happened when..."
  • Do not summarize the candidate's answer back to them at length. Acknowledge briefly, then probe.
  • Keep your turns SHORT. 1-3 sentences max. You are interviewing them, not presenting.
  • Do not explain what you're doing: never say "I'm now going to assess your X skills."

━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ OPENING ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Begin with a brief, warm introduction and an open first question. Example: "Hi [name], thanks for joining. Let's jump in — tell me about the most technically challenging project you've worked on recently." Do not list what you're going to assess. Just start.


3. Coverage Map Injection (B6)

The coverage map is injected as a clientContent text turn into the Gemini Live session before each AI response. It is NOT spoken — it is a text input, invisible to the candidate.

Injection format

[COVERAGE MAP — DO NOT SPEAK THIS]
{
  "skills": [
    { "id": "sk-eng-001", "label": "React / Frontend Development", "state": "partial", "probe_count": 2 },
    { "id": "communication", "label": "Communication", "state": "covered", "probe_count": 4 },
    { "id": "system-design", "label": "System Design", "state": "not_yet", "probe_count": 0 }
  ],
  "discovered": [
    { "label": "Micro-frontend Architecture", "state": "initiated", "probe_count": 1 }
  ],
  "time_remaining_minutes": 18,
  "priority_next": "system-design"
}

Injection timing

Candidate finishes speaking
    ↓
Gemini Live transcribes (real-time)
    ↓
Backend reads transcription
    ↓
Backend injects coverage map as clientContent text turn  ← happens here
    ↓
Gemini Live AI generates audio response (sees both transcript AND coverage map)
    ↓
AI speaks
    ↓ (async, does not block)
N7 coverage analyzer runs Gemini Flash
    ↓
N8 coverage map updated for next turn

Implementation note

Gemini Live accepts interleaved clientContent (text) and audio turns. The coverage map is sent as a clientContent turn with role: "user" and text content. The AI sees it as context but it does not appear in the audio stream.

Reference: Gemini Live API — BidiGenerateContentClientContent message type.


4. Coverage Analyzer Prompt (N7 — Gemini Flash)

This runs async after each candidate turn. Input is the last 6 transcript turns + current coverage map.

You are analyzing a transcript excerpt from a live skills assessment interview.

SKILL DEFINITIONS: {{#each skills}}

  • {{id}}: {{name}} — {{scope_include}} {{/each}}

CURRENT COVERAGE MAP: {{coverage_map_json}}

LAST 6 TRANSCRIPT TURNS: {{#each last_6_turns}} [{{speaker}}]: {{text}} {{/each}}

TASK:

  1. For each skill in the coverage map, determine if this exchange produced meaningful signal.
  2. Apply these state transition rules:
    • not_yet → initiated: AI asked an opening question on this skill in this exchange
    • initiated → partial: (a) at least one follow-up probe has occurred (probe_count >= 2) AND (b) you judge the signal is NOT yet sufficient for confident L1-L5 rating
    • partial → covered: (a) probe_count >= 2 AND (b) you judge there is enough behavioral evidence to confidently assign an L1-L5 level
    • HARD RULE: A skill CANNOT advance past "initiated" unless probe_count >= 2. Even if the first answer was exceptional.
  3. Update probe_count: increment by 1 for every exchange where this skill was meaningfully discussed.
  4. Check if the candidate mentioned any skill NOT in the coverage map. If yes, add it as a discovered skill with state "initiated".

CONFIDENCE TEST for "covered": Ask yourself: "If I had to assign L1-L5 to this skill right now, could I defend that rating with 2-3 specific quotes from the transcript?" If yes → covered. If no → partial.

OUTPUT (JSON only, no prose): { "skill_updates": [ { "id": "sk-eng-001", "new_state": "partial", "new_probe_count": 3, "reason": "Candidate described context splitting approach but hasn't addressed edge cases or testing strategy" } ], "discovered_skills": [ { "label": "Micro-frontend Architecture", "first_mention": "Candidate mentioned leading a micro-frontend migration at previous company" } ] }


5. Portfolio Generator Prompt (N10 — Gemini Pro)

This runs after session ends. Input is the full transcript + final coverage map + all skill definitions.

You are evaluating a completed skills assessment interview to produce a structured skill portfolio.

ROLE BEING ASSESSED: {{role_title}}

SKILL DEFINITIONS AND BEHAVIORAL ANCHORS: {{#each configured_skills}} ━━━━━━━━━━━━━━━ SKILL: {{name}} ({{id}}) SCOPE: {{scope_include}}

L1 — {{l1_anchor}} L2 — {{l2_anchor}} L3 — {{l3_anchor}} L4 — {{l4_anchor}} L5 — {{l5_anchor}} {{/each}}

UNIVERSAL L1-L5 ANCHORS (use for discovered skills): L1 — Executes with explicit guidance and close review. Understands conceptually but cannot apply independently. L2 — Executes independently on routine scope. Uses known patterns. Handles common cases but not edge cases. L3 — Executes complex, ambiguous scope. Makes tradeoffs. Handles edge cases. Can teach L1-L2. L4 — Defines standards and creates reusable systems. Resolves systemic problems. Cross-team impact. L5 — Org-level authority. Shapes how the skill is practiced. Rare.

FINAL COVERAGE MAP: {{coverage_map_json}}

FULL INTERVIEW TRANSCRIPT: {{full_transcript}}

━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ TASK ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

For EACH skill in the coverage map (both configured and discovered):

  1. FIND THE EVIDENCE Read all transcript turns where this skill was discussed. Identify the 2-3 most revealing quotes from the CANDIDATE (not the AI). A quote is revealing if it shows HOW they think, not just WHAT they know.

  2. ASSIGN A LEVEL Compare the candidate's actual behavior (from the transcript) to the L1-L5 anchors. Assign the highest level where you see CONSISTENT evidence, not just one strong moment. If the evidence is mixed (mostly L2 with one L3 moment), assign L2.

  3. WRITE THE COMPETENCY SUMMARY 2-3 sentences. Focus on patterns, not individual answers. What does this person reliably do at this skill? What's the ceiling? What's missing? Good: "Ahmad consistently handles complex state management challenges and demonstrates L3 architecture thinking. However, his testing strategy defaults to unit tests only, which is an L2 pattern. He would benefit from exposure to integration and e2e testing strategies before claiming full L3." Bad: "Ahmad knows React well and answered the questions correctly."

  4. ASSIGN CONFIDENCE high — probe_count >= 3 AND state = covered medium — probe_count = 2 OR state = partial low — probe_count <= 1 OR state = initiated

OUTPUT (JSON only): { "configured_skills": [ { "skill_id": "sk-eng-001", "skill_label": "React / Frontend Development", "level": 3, "confidence": "high", "evidence": [ ""I split the context into a read-only provider and a write provider to prevent re-renders in components that only consume state"", ""We introduced route-level code splitting which dropped our initial bundle from 2.1MB to 400KB"", ""For the test strategy I layered unit tests on pure functions, integration tests on the data-fetching layer, and e2e on critical user paths"" ], "competency_summary": "Ahmad demonstrates strong L3 proficiency in frontend development. He handles complex state architecture with clear tradeoff reasoning and owns performance optimization end-to-end. His testing strategy is mature for a mid-level engineer, covering unit through e2e. The main gap between L3 and L4 is that he has not yet defined team-wide standards or built reusable systems adopted by others." } ], "discovered_skills": [ { "skill_label": "Micro-frontend Architecture", "level": 2, "confidence": "low", "evidence": [ ""We split the monolith into four micro-frontends using Module Federation in webpack 5"" ], "competency_summary": "Ahmad has hands-on experience with micro-frontend architecture using Module Federation. Only briefly explored in this session — insufficient signal for a confident rating. Warrants a dedicated assessment if this skill is relevant to the role." } ] }


6. Probing Behavior Examples

These examples show the difference between robotic (wrong) and human-like (correct) AI behavior. These are NOT injected into the prompt — they are here to validate prompt quality during testing.

Example A: Probing a vague claim

CANDIDATE: "Yeah I've worked a lot with React, I know hooks pretty well."

❌ ROBOTIC: "Great. Next question — what is your experience with Redux?"

✅ HUMAN-LIKE: "What's a hook usage pattern you've found yourself reaching for that most engineers on your team don't use? And why does it work better in that case?"

Example B: Follow-up on a strong answer

CANDIDATE: "I split the context into read-only and write providers to prevent unnecessary re-renders.
            It cut our re-render count by about 60%."

❌ ROBOTIC: "Interesting. How familiar are you with performance profiling tools?"

✅ HUMAN-LIKE: "60% is meaningful. When you split those providers, how did you handle components that legitimately need both read and write access? Did that create any patterns that were hard to onboard new team members to?"

Example C: Discovering an off-agenda skill

CANDIDATE: "...and at Gojek we also broke the frontend into micro-frontends, which was a whole
            different challenge."

✅ CORRECT: "Oh interesting — tell me briefly about the architecture. How did you handle shared state across boundaries? [listens] Right. And what was the biggest mistake the team made early on? [listens] Okay, good. Let's come back to system design — when you're designing a system from scratch, where do you start?"

Example D: Natural topic transition

❌ ROBOTIC: "Okay, we've covered React. Now let's move on to communication skills.
             Tell me about a time you had a conflict with a colleague."

✅ HUMAN-LIKE: "The way you described pushing back on the architecture decision — walk me through how that conversation actually went. Who was in the room and how did you frame your concern?"


7. What the AI Must NOT Do

Engineers must test for these failure modes during QA:

Failure Description Test
Question list behavior AI asks pre-planned questions ignoring what candidate said Ask a question — does the AI's follow-up reference your specific answer?
Hollow affirmation AI says "Great answer!" before every follow-up Check if AI affirms every turn
Topic announcement AI says "Now let's talk about communication" Never acceptable
Skipping follow-up AI moves to next skill without probing the first answer Coverage map probe_count must reach 2 before initiated → partial
Answering for the candidate AI over-explains the question or hints at the answer "Can you give me an example of X?" should not include an example of X
Running out of things to ask AI says "I don't have more questions" before all skills are covered Coverage map must show all skills covered before session end

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