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quiz A (P0): accept 'adaptive' difficulty, single-source /api/quiz/config, stable error envelope #540

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#547
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quiz A (P0): accept 'adaptive' difficulty, single-source /api/quiz/config, stable error envelope#540
#547
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AndresL230
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P0Critical / blockerbackendBackend / APIbugSomething isn't working

Description

@AndresL230
AndresL230
opened on Aug 12, 2026

Part of the pre-revamp quiz repair batch under epic #537 (2026-08-12 quiz product audit). Workstream A — the only piece that ships standalone, today.

Verified defects

  • POST /api/quiz/generate rejects adaptive: routes/quiz.py:39 (VALID_DIFFICULTIES = {"easy","medium","hard"}) → 400 at routes/quiz.py:298-303. Generation is already adaptive server-side (agents/quiz.py:116-127 — difficulty mix shifts ±1 step from recent_attempts.accuracy), so the option is dead UI, not missing capability.
  • num_questions capped ge=1, le=10 at models/__init__.py:49; the UI offers "15 questions" (frontend/src/components/QuizPanel.tsx:61) → guaranteed 422.
  • Errors reach the client as raw FastAPI/Pydantic JSON with request_id (main.py:186-213) — no stable machine codes, exc.errors() shown to students.

Work

A1 — make adaptive a real difficulty. Accept it at the route; resolve to a concrete per-question mix inside the agent call (the agent contract already carries per-question difficulty — agents/quiz.py:58 — so this is expressible today). Response adds resolved_difficulty (overall) and keeps per-question difficulty. Constraint: quiz_attempts.difficulty CHECK allows only easy/medium/hard (db/migrations/0025_study_integrity.sql:99) — needs a small append-only migration to store the requested value.

A2 — one source of truth for option lists.GET /api/quiz/config returning allowed num_questions values, min/max, difficulties, question types (mcq only). Cap moves to a named constant read by both the Pydantic model and the endpoint. Decide the real cap deliberately with measured latency/token cost of 15- and 20-question generations on gemini-2.5-flash-lite. Note: the current 10-question cap is not arbitrary — Quiz.questions is max_length=10 because larger schemas tripped Gemini's constrained-decoding "too many states for serving" on flash-lite (agents/quiz.py:77-80); the cap decision must account for that.

A3 — stable error envelope. Every quiz-route 4xx/5xx returns { error: { code, message, detail?, request_id } }; codes in one enum module (QUIZ_DIFFICULTY_INVALID, QUIZ_COUNT_OUT_OF_RANGE, QUIZ_GENERATION_FAILED, QUIZ_ATTEMPT_ALREADY_COMPLETED, …). Keep the legacy detail key alongside so the current client keeps working.

Acceptance

  • Client can never offer a value the route rejects (config-driven).
  • adaptive generates, stores, and echoes honestly what was chosen.
  • Subcutaneous HTTP→real-DB tests for each difficulty incl. adaptive + boundary counts (Chapter 1 lanes, no MagicMock on DB assertions).

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quiz A (P0): accept 'adaptive' difficulty, single-source /api/quiz/config, stable error envelope · Issue #540 · SaplingLearn/Sapling · GitHub
    Skip to content
    quiz A (P0): accept 'adaptive' difficulty, single-source /api/quiz/config, stable error envelope #540
    Closed
    #547
    Closed
    quiz A (P0): accept 'adaptive' difficulty, single-source /api/quiz/config, stable error envelope#540
    #547
    Assignees
    AndresL230
    Labels
    P0Critical / blockerbackendBackend / APIbugSomething isn't working
    Description
    @AndresL230
    AndresL230
    opened on Aug 12, 2026
    Part of the pre-revamp quiz repair batch under epic #537 (2026-08-12 quiz product audit). Workstream A — the only piece that ships standalone, today.
    Verified defects
    • POST /api/quiz/generate rejects adaptive: routes/quiz.py:39 (VALID_DIFFICULTIES = {"easy","medium","hard"}) → 400 at routes/quiz.py:298-303. Generation is already adaptive server-side (agents/quiz.py:116-127 — difficulty mix shifts ±1 step from recent_attempts.accuracy), so the option is dead UI, not missing capability.
    • num_questions capped ge=1, le=10 at models/__init__.py:49; the UI offers "15 questions" (frontend/src/components/QuizPanel.tsx:61) → guaranteed 422.
    • Errors reach the client as raw FastAPI/Pydantic JSON with request_id (main.py:186-213) — no stable machine codes, exc.errors() shown to students.
    Work
    A1 — make adaptive a real difficulty. Accept it at the route; resolve to a concrete per-question mix inside the agent call (the agent contract already carries per-question difficulty — agents/quiz.py:58 — so this is expressible today). Response adds resolved_difficulty (overall) and keeps per-question difficulty. Constraint: quiz_attempts.difficulty CHECK allows only easy/medium/hard (db/migrations/0025_study_integrity.sql:99) — needs a small append-only migration to store the requested value.
    A2 — one source of truth for option lists.GET /api/quiz/config returning allowed num_questions values, min/max, difficulties, question types (mcq only). Cap moves to a named constant read by both the Pydantic model and the endpoint. Decide the real cap deliberately with measured latency/token cost of 15- and 20-question generations on gemini-2.5-flash-lite. Note: the current 10-question cap is not arbitrary — Quiz.questions is max_length=10 because larger schemas tripped Gemini's constrained-decoding "too many states for serving" on flash-lite (agents/quiz.py:77-80); the cap decision must account for that.
    A3 — stable error envelope. Every quiz-route 4xx/5xx returns { error: { code, message, detail?, request_id } }; codes in one enum module (QUIZ_DIFFICULTY_INVALID, QUIZ_COUNT_OUT_OF_RANGE, QUIZ_GENERATION_FAILED, QUIZ_ATTEMPT_ALREADY_COMPLETED, …). Keep the legacy detail key alongside so the current client keeps working.
    Acceptance
    • Client can never offer a value the route rejects (config-driven).
    • adaptive generates, stores, and echoes honestly what was chosen.
    • Subcutaneous HTTP→real-DB tests for each difficulty incl. adaptive + boundary counts (Chapter 1 lanes, no MagicMock on DB assertions).
    Metadata
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    Labels
    P0Critical / blockerbackendBackend / APIbugSomething isn't working
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quiz A (P0): accept 'adaptive' difficulty, single-source /api/quiz/config, stable error envelope · Issue #540 · SaplingLearn/Sapling · GitHub
      Skip to content
      quiz A (P0): accept 'adaptive' difficulty, single-source /api/quiz/config, stable error envelope #540
      Closed
      #547
      Closed
      quiz A (P0): accept 'adaptive' difficulty, single-source /api/quiz/config, stable error envelope#540
      #547
      Assignees
      AndresL230
      Labels
      P0Critical / blockerbackendBackend / APIbugSomething isn't working
      Description
      @AndresL230
      AndresL230
      opened on Aug 12, 2026
      Part of the pre-revamp quiz repair batch under epic #537 (2026-08-12 quiz product audit). Workstream A — the only piece that ships standalone, today.
      Verified defects
      • POST /api/quiz/generate rejects adaptive: routes/quiz.py:39 (VALID_DIFFICULTIES = {"easy","medium","hard"}) → 400 at routes/quiz.py:298-303. Generation is already adaptive server-side (agents/quiz.py:116-127 — difficulty mix shifts ±1 step from recent_attempts.accuracy), so the option is dead UI, not missing capability.
      • num_questions capped ge=1, le=10 at models/__init__.py:49; the UI offers "15 questions" (frontend/src/components/QuizPanel.tsx:61) → guaranteed 422.
      • Errors reach the client as raw FastAPI/Pydantic JSON with request_id (main.py:186-213) — no stable machine codes, exc.errors() shown to students.
      Work
      A1 — make adaptive a real difficulty. Accept it at the route; resolve to a concrete per-question mix inside the agent call (the agent contract already carries per-question difficulty — agents/quiz.py:58 — so this is expressible today). Response adds resolved_difficulty (overall) and keeps per-question difficulty. Constraint: quiz_attempts.difficulty CHECK allows only easy/medium/hard (db/migrations/0025_study_integrity.sql:99) — needs a small append-only migration to store the requested value.
      A2 — one source of truth for option lists.GET /api/quiz/config returning allowed num_questions values, min/max, difficulties, question types (mcq only). Cap moves to a named constant read by both the Pydantic model and the endpoint. Decide the real cap deliberately with measured latency/token cost of 15- and 20-question generations on gemini-2.5-flash-lite. Note: the current 10-question cap is not arbitrary — Quiz.questions is max_length=10 because larger schemas tripped Gemini's constrained-decoding "too many states for serving" on flash-lite (agents/quiz.py:77-80); the cap decision must account for that.
      A3 — stable error envelope. Every quiz-route 4xx/5xx returns { error: { code, message, detail?, request_id } }; codes in one enum module (QUIZ_DIFFICULTY_INVALID, QUIZ_COUNT_OUT_OF_RANGE, QUIZ_GENERATION_FAILED, QUIZ_ATTEMPT_ALREADY_COMPLETED, …). Keep the legacy detail key alongside so the current client keeps working.
      Acceptance
      • Client can never offer a value the route rejects (config-driven).
      • adaptive generates, stores, and echoes honestly what was chosen.
      • Subcutaneous HTTP→real-DB tests for each difficulty incl. adaptive + boundary counts (Chapter 1 lanes, no MagicMock on DB assertions).
      Metadata
      Metadata
      Assignees
      Labels
      P0Critical / blockerbackendBackend / APIbugSomething isn't working
      Type
      No type
      Projects
      No projects
        Milestone
        No milestone
        Relationships
        None yet
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        No branches or pull requests
        Issue actions
        
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try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
quiz A (P0): accept 'adaptive' difficulty, single-source /api/quiz/config, stable error envelope · Issue #540 · SaplingLearn/Sapling · GitHub
        Skip to content
        quiz A (P0): accept 'adaptive' difficulty, single-source /api/quiz/config, stable error envelope #540
        Closed
        #547
        Closed
        quiz A (P0): accept 'adaptive' difficulty, single-source /api/quiz/config, stable error envelope#540
        #547
        Assignees
        AndresL230
        Labels
        P0Critical / blockerbackendBackend / APIbugSomething isn't working
        Description
        @AndresL230
        AndresL230
        opened on Aug 12, 2026
        Part of the pre-revamp quiz repair batch under epic #537 (2026-08-12 quiz product audit). Workstream A — the only piece that ships standalone, today.
        Verified defects
        • POST /api/quiz/generate rejects adaptive: routes/quiz.py:39 (VALID_DIFFICULTIES = {"easy","medium","hard"}) → 400 at routes/quiz.py:298-303. Generation is already adaptive server-side (agents/quiz.py:116-127 — difficulty mix shifts ±1 step from recent_attempts.accuracy), so the option is dead UI, not missing capability.
        • num_questions capped ge=1, le=10 at models/__init__.py:49; the UI offers "15 questions" (frontend/src/components/QuizPanel.tsx:61) → guaranteed 422.
        • Errors reach the client as raw FastAPI/Pydantic JSON with request_id (main.py:186-213) — no stable machine codes, exc.errors() shown to students.
        Work
        A1 — make adaptive a real difficulty. Accept it at the route; resolve to a concrete per-question mix inside the agent call (the agent contract already carries per-question difficulty — agents/quiz.py:58 — so this is expressible today). Response adds resolved_difficulty (overall) and keeps per-question difficulty. Constraint: quiz_attempts.difficulty CHECK allows only easy/medium/hard (db/migrations/0025_study_integrity.sql:99) — needs a small append-only migration to store the requested value.
        A2 — one source of truth for option lists.GET /api/quiz/config returning allowed num_questions values, min/max, difficulties, question types (mcq only). Cap moves to a named constant read by both the Pydantic model and the endpoint. Decide the real cap deliberately with measured latency/token cost of 15- and 20-question generations on gemini-2.5-flash-lite. Note: the current 10-question cap is not arbitrary — Quiz.questions is max_length=10 because larger schemas tripped Gemini's constrained-decoding "too many states for serving" on flash-lite (agents/quiz.py:77-80); the cap decision must account for that.
        A3 — stable error envelope. Every quiz-route 4xx/5xx returns { error: { code, message, detail?, request_id } }; codes in one enum module (QUIZ_DIFFICULTY_INVALID, QUIZ_COUNT_OUT_OF_RANGE, QUIZ_GENERATION_FAILED, QUIZ_ATTEMPT_ALREADY_COMPLETED, …). Keep the legacy detail key alongside so the current client keeps working.
        Acceptance
        • Client can never offer a value the route rejects (config-driven).
        • adaptive generates, stores, and echoes honestly what was chosen.
        • Subcutaneous HTTP→real-DB tests for each difficulty incl. adaptive + boundary counts (Chapter 1 lanes, no MagicMock on DB assertions).
        Metadata
        Metadata
        Assignees
        Labels
        P0Critical / blockerbackendBackend / APIbugSomething isn't working
        Type
        No type
        Projects
        No projects
          Milestone
          No milestone
          Relationships
          None yet
          Development
          No branches or pull requests
          Issue actions
          
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})();
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try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '
quiz A (P0): accept 'adaptive' difficulty, single-source /api/quiz/config, stable error envelope · Issue #540 · SaplingLearn/Sapling · GitHub
          Skip to content
          quiz A (P0): accept 'adaptive' difficulty, single-source /api/quiz/config, stable error envelope #540
          Closed
          #547
          Closed
          quiz A (P0): accept 'adaptive' difficulty, single-source /api/quiz/config, stable error envelope#540
          #547
          Assignees
          AndresL230
          Labels
          P0Critical / blockerbackendBackend / APIbugSomething isn't working
          Description
          @AndresL230
          AndresL230
          opened on Aug 12, 2026
          Part of the pre-revamp quiz repair batch under epic #537 (2026-08-12 quiz product audit). Workstream A — the only piece that ships standalone, today.
          Verified defects
          • POST /api/quiz/generate rejects adaptive: routes/quiz.py:39 (VALID_DIFFICULTIES = {"easy","medium","hard"}) → 400 at routes/quiz.py:298-303. Generation is already adaptive server-side (agents/quiz.py:116-127 — difficulty mix shifts ±1 step from recent_attempts.accuracy), so the option is dead UI, not missing capability.
          • num_questions capped ge=1, le=10 at models/__init__.py:49; the UI offers "15 questions" (frontend/src/components/QuizPanel.tsx:61) → guaranteed 422.
          • Errors reach the client as raw FastAPI/Pydantic JSON with request_id (main.py:186-213) — no stable machine codes, exc.errors() shown to students.
          Work
          A1 — make adaptive a real difficulty. Accept it at the route; resolve to a concrete per-question mix inside the agent call (the agent contract already carries per-question difficulty — agents/quiz.py:58 — so this is expressible today). Response adds resolved_difficulty (overall) and keeps per-question difficulty. Constraint: quiz_attempts.difficulty CHECK allows only easy/medium/hard (db/migrations/0025_study_integrity.sql:99) — needs a small append-only migration to store the requested value.
          A2 — one source of truth for option lists.GET /api/quiz/config returning allowed num_questions values, min/max, difficulties, question types (mcq only). Cap moves to a named constant read by both the Pydantic model and the endpoint. Decide the real cap deliberately with measured latency/token cost of 15- and 20-question generations on gemini-2.5-flash-lite. Note: the current 10-question cap is not arbitrary — Quiz.questions is max_length=10 because larger schemas tripped Gemini's constrained-decoding "too many states for serving" on flash-lite (agents/quiz.py:77-80); the cap decision must account for that.
          A3 — stable error envelope. Every quiz-route 4xx/5xx returns { error: { code, message, detail?, request_id } }; codes in one enum module (QUIZ_DIFFICULTY_INVALID, QUIZ_COUNT_OUT_OF_RANGE, QUIZ_GENERATION_FAILED, QUIZ_ATTEMPT_ALREADY_COMPLETED, …). Keep the legacy detail key alongside so the current client keeps working.
          Acceptance
          • Client can never offer a value the route rejects (config-driven).
          • adaptive generates, stores, and echoes honestly what was chosen.
          • Subcutaneous HTTP→real-DB tests for each difficulty incl. adaptive + boundary counts (Chapter 1 lanes, no MagicMock on DB assertions).
          Metadata
          Metadata
          Assignees
          Labels
          P0Critical / blockerbackendBackend / APIbugSomething isn't working
          Type
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          Projects
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            No branches or pull requests
            Issue actions
            
, 'i');
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var __m = "*";
var __re = new RegExp('^' + ".*" + '
quiz A (P0): accept 'adaptive' difficulty, single-source /api/quiz/config, stable error envelope · Issue #540 · SaplingLearn/Sapling · GitHub
            Skip to content
            quiz A (P0): accept 'adaptive' difficulty, single-source /api/quiz/config, stable error envelope #540
            Closed
            #547
            Closed
            quiz A (P0): accept 'adaptive' difficulty, single-source /api/quiz/config, stable error envelope#540
            #547
            Assignees
            AndresL230
            Labels
            P0Critical / blockerbackendBackend / APIbugSomething isn't working
            Description
            @AndresL230
            AndresL230
            opened on Aug 12, 2026
            Part of the pre-revamp quiz repair batch under epic #537 (2026-08-12 quiz product audit). Workstream A — the only piece that ships standalone, today.
            Verified defects
            • POST /api/quiz/generate rejects adaptive: routes/quiz.py:39 (VALID_DIFFICULTIES = {"easy","medium","hard"}) → 400 at routes/quiz.py:298-303. Generation is already adaptive server-side (agents/quiz.py:116-127 — difficulty mix shifts ±1 step from recent_attempts.accuracy), so the option is dead UI, not missing capability.
            • num_questions capped ge=1, le=10 at models/__init__.py:49; the UI offers "15 questions" (frontend/src/components/QuizPanel.tsx:61) → guaranteed 422.
            • Errors reach the client as raw FastAPI/Pydantic JSON with request_id (main.py:186-213) — no stable machine codes, exc.errors() shown to students.
            Work
            A1 — make adaptive a real difficulty. Accept it at the route; resolve to a concrete per-question mix inside the agent call (the agent contract already carries per-question difficulty — agents/quiz.py:58 — so this is expressible today). Response adds resolved_difficulty (overall) and keeps per-question difficulty. Constraint: quiz_attempts.difficulty CHECK allows only easy/medium/hard (db/migrations/0025_study_integrity.sql:99) — needs a small append-only migration to store the requested value.
            A2 — one source of truth for option lists.GET /api/quiz/config returning allowed num_questions values, min/max, difficulties, question types (mcq only). Cap moves to a named constant read by both the Pydantic model and the endpoint. Decide the real cap deliberately with measured latency/token cost of 15- and 20-question generations on gemini-2.5-flash-lite. Note: the current 10-question cap is not arbitrary — Quiz.questions is max_length=10 because larger schemas tripped Gemini's constrained-decoding "too many states for serving" on flash-lite (agents/quiz.py:77-80); the cap decision must account for that.
            A3 — stable error envelope. Every quiz-route 4xx/5xx returns { error: { code, message, detail?, request_id } }; codes in one enum module (QUIZ_DIFFICULTY_INVALID, QUIZ_COUNT_OUT_OF_RANGE, QUIZ_GENERATION_FAILED, QUIZ_ATTEMPT_ALREADY_COMPLETED, …). Keep the legacy detail key alongside so the current client keeps working.
            Acceptance
            • Client can never offer a value the route rejects (config-driven).
            • adaptive generates, stores, and echoes honestly what was chosen.
            • Subcutaneous HTTP→real-DB tests for each difficulty incl. adaptive + boundary counts (Chapter 1 lanes, no MagicMock on DB assertions).
            Metadata
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            P0Critical / blockerbackendBackend / APIbugSomething isn't working
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quiz A (P0): accept 'adaptive' difficulty, single-source /api/quiz/config, stable error envelope · Issue #540 · SaplingLearn/Sapling · GitHub
              Skip to content
              quiz A (P0): accept 'adaptive' difficulty, single-source /api/quiz/config, stable error envelope #540
              Closed
              #547
              Closed
              quiz A (P0): accept 'adaptive' difficulty, single-source /api/quiz/config, stable error envelope#540
              #547
              Assignees
              AndresL230
              Labels
              P0Critical / blockerbackendBackend / APIbugSomething isn't working
              Description
              @AndresL230
              AndresL230
              opened on Aug 12, 2026
              Part of the pre-revamp quiz repair batch under epic #537 (2026-08-12 quiz product audit). Workstream A — the only piece that ships standalone, today.
              Verified defects
              • POST /api/quiz/generate rejects adaptive: routes/quiz.py:39 (VALID_DIFFICULTIES = {"easy","medium","hard"}) → 400 at routes/quiz.py:298-303. Generation is already adaptive server-side (agents/quiz.py:116-127 — difficulty mix shifts ±1 step from recent_attempts.accuracy), so the option is dead UI, not missing capability.
              • num_questions capped ge=1, le=10 at models/__init__.py:49; the UI offers "15 questions" (frontend/src/components/QuizPanel.tsx:61) → guaranteed 422.
              • Errors reach the client as raw FastAPI/Pydantic JSON with request_id (main.py:186-213) — no stable machine codes, exc.errors() shown to students.
              Work
              A1 — make adaptive a real difficulty. Accept it at the route; resolve to a concrete per-question mix inside the agent call (the agent contract already carries per-question difficulty — agents/quiz.py:58 — so this is expressible today). Response adds resolved_difficulty (overall) and keeps per-question difficulty. Constraint: quiz_attempts.difficulty CHECK allows only easy/medium/hard (db/migrations/0025_study_integrity.sql:99) — needs a small append-only migration to store the requested value.
              A2 — one source of truth for option lists.GET /api/quiz/config returning allowed num_questions values, min/max, difficulties, question types (mcq only). Cap moves to a named constant read by both the Pydantic model and the endpoint. Decide the real cap deliberately with measured latency/token cost of 15- and 20-question generations on gemini-2.5-flash-lite. Note: the current 10-question cap is not arbitrary — Quiz.questions is max_length=10 because larger schemas tripped Gemini's constrained-decoding "too many states for serving" on flash-lite (agents/quiz.py:77-80); the cap decision must account for that.
              A3 — stable error envelope. Every quiz-route 4xx/5xx returns { error: { code, message, detail?, request_id } }; codes in one enum module (QUIZ_DIFFICULTY_INVALID, QUIZ_COUNT_OUT_OF_RANGE, QUIZ_GENERATION_FAILED, QUIZ_ATTEMPT_ALREADY_COMPLETED, …). Keep the legacy detail key alongside so the current client keeps working.
              Acceptance
              • Client can never offer a value the route rejects (config-driven).
              • adaptive generates, stores, and echoes honestly what was chosen.
              • Subcutaneous HTTP→real-DB tests for each difficulty incl. adaptive + boundary counts (Chapter 1 lanes, no MagicMock on DB assertions).
              Metadata
              Metadata
              Assignees
              Labels
              P0Critical / blockerbackendBackend / APIbugSomething isn't working
              Type
              No type
              Projects
              No projects
                Milestone
                No milestone
                Relationships
                None yet
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                No branches or pull requests
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quiz A (P0): accept 'adaptive' difficulty, single-source /api/quiz/config, stable error envelope · Issue #540 · SaplingLearn/Sapling · GitHub
                Skip to content
                quiz A (P0): accept 'adaptive' difficulty, single-source /api/quiz/config, stable error envelope #540
                Closed
                #547
                Closed
                quiz A (P0): accept 'adaptive' difficulty, single-source /api/quiz/config, stable error envelope#540
                #547
                Assignees
                AndresL230
                Labels
                P0Critical / blockerbackendBackend / APIbugSomething isn't working
                Description
                @AndresL230
                AndresL230
                opened on Aug 12, 2026
                Part of the pre-revamp quiz repair batch under epic #537 (2026-08-12 quiz product audit). Workstream A — the only piece that ships standalone, today.
                Verified defects
                • POST /api/quiz/generate rejects adaptive: routes/quiz.py:39 (VALID_DIFFICULTIES = {"easy","medium","hard"}) → 400 at routes/quiz.py:298-303. Generation is already adaptive server-side (agents/quiz.py:116-127 — difficulty mix shifts ±1 step from recent_attempts.accuracy), so the option is dead UI, not missing capability.
                • num_questions capped ge=1, le=10 at models/__init__.py:49; the UI offers "15 questions" (frontend/src/components/QuizPanel.tsx:61) → guaranteed 422.
                • Errors reach the client as raw FastAPI/Pydantic JSON with request_id (main.py:186-213) — no stable machine codes, exc.errors() shown to students.
                Work
                A1 — make adaptive a real difficulty. Accept it at the route; resolve to a concrete per-question mix inside the agent call (the agent contract already carries per-question difficulty — agents/quiz.py:58 — so this is expressible today). Response adds resolved_difficulty (overall) and keeps per-question difficulty. Constraint: quiz_attempts.difficulty CHECK allows only easy/medium/hard (db/migrations/0025_study_integrity.sql:99) — needs a small append-only migration to store the requested value.
                A2 — one source of truth for option lists.GET /api/quiz/config returning allowed num_questions values, min/max, difficulties, question types (mcq only). Cap moves to a named constant read by both the Pydantic model and the endpoint. Decide the real cap deliberately with measured latency/token cost of 15- and 20-question generations on gemini-2.5-flash-lite. Note: the current 10-question cap is not arbitrary — Quiz.questions is max_length=10 because larger schemas tripped Gemini's constrained-decoding "too many states for serving" on flash-lite (agents/quiz.py:77-80); the cap decision must account for that.
                A3 — stable error envelope. Every quiz-route 4xx/5xx returns { error: { code, message, detail?, request_id } }; codes in one enum module (QUIZ_DIFFICULTY_INVALID, QUIZ_COUNT_OUT_OF_RANGE, QUIZ_GENERATION_FAILED, QUIZ_ATTEMPT_ALREADY_COMPLETED, …). Keep the legacy detail key alongside so the current client keeps working.
                Acceptance
                • Client can never offer a value the route rejects (config-driven).
                • adaptive generates, stores, and echoes honestly what was chosen.
                • Subcutaneous HTTP→real-DB tests for each difficulty incl. adaptive + boundary counts (Chapter 1 lanes, no MagicMock on DB assertions).
                Metadata
                Metadata
                Assignees
                Labels
                P0Critical / blockerbackendBackend / APIbugSomething isn't working
                Type
                No type
                Projects
                No projects
                  Milestone
                  No milestone
                  Relationships
                  None yet
                  Development
                  No branches or pull requests
                  Issue actions