diff --git a/.github/workflows/idric-core.yml b/.github/workflows/idric-core.yml
index bc946a3..37d3dce 100644
--- a/.github/workflows/idric-core.yml
+++ b/.github/workflows/idric-core.yml
@@ -29,6 +29,9 @@ jobs:
       - name: Exercise filesystem category and hot views
         run: sh bin/ci_browser_foundation.grease exercise-filesystem-views
 
+      - name: Exercise saved-tab text question mock
+        run: sh bin/ci_browser_foundation.grease exercise-tab-qa
+
       - name: Install system dependencies through Grease
         run: sh bin/ci_browser_foundation.grease install-dependencies
 
diff --git a/README.md b/README.md
index 283b612..d170526 100644
--- a/README.md
+++ b/README.md
@@ -18,6 +18,8 @@ The browser core owns resource, tab, event, and task identity; sleeping and waki
 - `docs/filesystem-views.md` — category links, `_active`, and the requested `hot/` presentation set
 - `docs/storage-model.md` — identity levels and canonical, proposed, and derived state
 - `docs/developer-workbench.md` — fixture and memory-pressure harness
+- `docs/vector-index.md` — readable multi-model vector views and rebuildable Float32 query caches
+- `docs/tab-qa-mock.md` — console questions over saved reading pages with replaceable processing stages
 - `experiments/category-hyperplanes/README.md` — disposable embedding and explicit affine-separator probe
 - `experiments/embedding-models/README.md` — pinned tiny ONNX models and an end-to-end filesystem-index comparison
 
diff --git a/bin/ask_saved_pages.grease b/bin/ask_saved_pages.grease
new file mode 100755
index 0000000..42e6a6c
--- /dev/null
+++ b/bin/ask_saved_pages.grease
@@ -0,0 +1,30 @@
+#!/bin/sh
+set -eu
+
+repository_root=$(CDPATH= cd -- "$(dirname -- "$0")/.." && pwd)
+export IB_TAB_QA_REPOSITORY_ROOT="$repository_root"
+. "$repository_root/lib/tab_qa.grease"
+
+case "${1:-}" in
+  --index)
+    test "$#" -eq 1 || exit 2
+    ib_tab_qa_build_index
+    ;;
+  --inspect)
+    test "$#" -eq 1 || exit 2
+    ib_tab_qa_inspect
+    ;;
+  --help)
+    printf '%s\n' \
+      "usage: $0 [--index|--inspect|QUESTION]" \
+      'With no argument, read one question from the console.'
+    ;;
+  '')
+    printf 'question> ' >&2
+    IFS= read -r question || exit 1
+    ib_tab_qa_answer "$question"
+    ;;
+  *)
+    ib_tab_qa_answer "$*"
+    ;;
+esac
diff --git a/bin/ci_browser_foundation.grease b/bin/ci_browser_foundation.grease
index 27ec674..545b23d 100755
--- a/bin/ci_browser_foundation.grease
+++ b/bin/ci_browser_foundation.grease
@@ -74,6 +74,19 @@ exercise_filesystem_views() {
   sh tests/test_filesystem_views.grease
 }
 
+exercise_tab_qa() {
+  cd "$repository_root"
+  sh -n lib/tab_qa.grease
+  sh -n bin/ask_saved_pages.grease
+  sh -n bin/mock_tab_model.grease
+  sh -n bin/mock_tab_qa_reducer.grease
+  sh -n tests/test_mock_tab_model.grease
+  sh -n tests/test_tab_qa_pipeline.grease
+  make -C native/vector-index
+  sh tests/test_mock_tab_model.grease
+  sh tests/test_tab_qa_pipeline.grease
+}
+
 exercise_workbench() {
   cd "$repository_root"
   sh -n tests/test_real_world_url_fixture.grease
@@ -199,11 +212,12 @@ case "${1:-}" in
   exercise-workbench) exercise_workbench ;;
   exercise-file-store) exercise_file_store ;;
   exercise-filesystem-views) exercise_filesystem_views ;;
+  exercise-tab-qa) exercise_tab_qa ;;
   exercise-scientific-media) exercise_scientific_media ;;
   exercise-live-arxiv) exercise_live_arxiv ;;
   exercise-live-arxiv-prepaint) exercise_live_arxiv_prepaint ;;
   *)
-    printf 'usage: %s {install-dependencies|build-idric|verify-pdf-harvester|exercise-information|exercise-core|exercise-workbench|exercise-file-store|exercise-filesystem-views|exercise-scientific-media|exercise-live-arxiv|exercise-live-arxiv-prepaint}\n' "$0" >&2
+    printf 'usage: %s {install-dependencies|build-idric|verify-pdf-harvester|exercise-information|exercise-core|exercise-workbench|exercise-file-store|exercise-filesystem-views|exercise-tab-qa|exercise-scientific-media|exercise-live-arxiv|exercise-live-arxiv-prepaint}\n' "$0" >&2
     exit 2
     ;;
 esac
diff --git a/bin/mock_tab_model.grease b/bin/mock_tab_model.grease
new file mode 100755
index 0000000..d478ac4
--- /dev/null
+++ b/bin/mock_tab_model.grease
@@ -0,0 +1,116 @@
+#!/bin/sh
+set -eu
+
+model_name=mock-token-i8-v1
+dimensions=32
+
+inspect_model() {
+  printf '%s\n' \
+    "model=$model_name" \
+    'available=True' \
+    'model-kind=deterministic-token-test-double' \
+    'llm=False' \
+    'quantization=int8-counts' \
+    "dimensions=$dimensions" \
+    'tasks=embedding,extractive-answer'
+}
+
+embed_text() {
+  awk -v dimensions="$dimensions" '
+    function token_slot(token,    alphabet, character, hash, index_in_alphabet, position) {
+      alphabet = "abcdefghijklmnopqrstuvwxyz0123456789"
+      hash = 0
+      for (position = 1; position <= length(token); position++) {
+        character = substr(token, position, 1)
+        index_in_alphabet = index(alphabet, character)
+        hash = (hash * 37 + index_in_alphabet) % dimensions
+      }
+      return hash + 1
+    }
+    {
+      text = tolower($0)
+      gsub(/[^[:alnum:]]+/, " ", text)
+      token_count = split(text, tokens, / +/)
+      for (token_index = 1; token_index <= token_count; token_index++) {
+        token = tokens[token_index]
+        if (length(token) < 2)
+          continue
+        slot = token_slot(token)
+        if (values[slot] < 127)
+          values[slot]++
+      }
+    }
+    END {
+      for (slot = 1; slot <= dimensions; slot++)
+        printf "%s%d", slot == 1 ? "" : " ", values[slot] + 0
+      printf "\n"
+    }
+  '
+}
+
+answer_from_document() {
+  question=$1
+  document=$2
+  test -s "$document" || {
+    printf 'mock tab model: source document is empty: %s\n' "$document" >&2
+    return 1
+  }
+
+  awk -v question="$question" '
+    BEGIN {
+      normalized_question = tolower(question)
+      gsub(/[^[:alnum:]]+/, " ", normalized_question)
+      question_count = split(normalized_question, question_tokens, / +/)
+      for (question_index = 1; question_index <= question_count; question_index++)
+        if (length(question_tokens[question_index]) >= 2)
+          wanted[question_tokens[question_index]] = 1
+    }
+    NF {
+      if (first_line == "")
+        first_line = $0
+      normalized_line = tolower($0)
+      gsub(/[^[:alnum:]]+/, " ", normalized_line)
+      line_count = split(normalized_line, line_tokens, / +/)
+      score = 0
+      for (line_index = 1; line_index <= line_count; line_index++) {
+        token = line_tokens[line_index]
+        if (token in wanted && seen_on_line[token] != NR) {
+          score++
+          seen_on_line[token] = NR
+        }
+      }
+      if (best_line == "" || score > best_score) {
+        best_line = $0
+        best_score = score
+      }
+    }
+    END {
+      if (best_line != "")
+        print best_line
+      else if (first_line != "")
+        print first_line
+    }
+  ' "$document"
+}
+
+case "${1:-}" in
+  inspect)
+    test "$#" -eq 1 || exit 2
+    inspect_model
+    ;;
+  embed)
+    test "$#" -eq 1 || exit 2
+    embed_text
+    ;;
+  answer)
+    test "$#" -eq 3 || {
+      printf 'usage: %s answer QUESTION DOCUMENT\n' "$0" >&2
+      exit 2
+    }
+    answer_from_document "$2" "$3"
+    ;;
+  *)
+    printf 'usage: %s {inspect|embed|answer QUESTION DOCUMENT}\n' "$0" >&2
+    exit 2
+    ;;
+esac
diff --git a/bin/mock_tab_qa_reducer.grease b/bin/mock_tab_qa_reducer.grease
new file mode 100755
index 0000000..5619dc3
--- /dev/null
+++ b/bin/mock_tab_qa_reducer.grease
@@ -0,0 +1,68 @@
+#!/bin/sh
+set -eu
+
+reducer_name=mock-single-member-weighted-reducer-v1
+
+inspect_reducer() {
+  printf '%s\n' \
+    "reducer=$reducer_name" \
+    'available=True' \
+    'ensemble=single-member-test-double' \
+    'member-count=1' \
+    'xgboost=False'
+}
+
+reduce_candidate() {
+  retrieval_score=$1
+  source_document=$2
+  report=${IB_TAB_QA_REDUCER_REPORT:?IB_TAB_QA_REDUCER_REPORT must name the reducer report}
+  candidate=$(sed -n '1p')
+
+  test -n "$candidate" || {
+    printf 'mock reducer: model candidate is empty\n' >&2
+    return 1
+  }
+  test -s "$source_document" || {
+    printf 'mock reducer: source document is unavailable\n' >&2
+    return 1
+  }
+  awk -v value="$retrieval_score" 'BEGIN {
+    numeric = value ~ /^[-+]?([0-9]+([.][0-9]*)?|[.][0-9]+)([eE][-+]?[0-9]+)?$/
+    exit !numeric
+  }' || {
+    printf 'mock reducer: retrieval score is not numeric\n' >&2
+    return 1
+  }
+
+  printf '%s\n' \
+    "reducer=$reducer_name" \
+    'ensemble-stage-ran=True' \
+    'member-count=1' \
+    'checks-run=3' \
+    'candidate-nonempty=True' \
+    'source-readable=True' \
+    'score-numeric=True' \
+    "aggregate-score=$retrieval_score" > "$report"
+
+  # This one-member reducer deliberately preserves the model text. A later
+  # voting, bagging, rank-aggregation, or XGBoost adapter occupies this stage.
+  printf '%s\n' "$candidate"
+}
+
+case "${1:-}" in
+  inspect)
+    test "$#" -eq 1 || exit 2
+    inspect_reducer
+    ;;
+  reduce)
+    test "$#" -eq 3 || {
+      printf 'usage: %s reduce RETRIEVAL_SCORE SOURCE_DOCUMENT < candidate.txt\n' "$0" >&2
+      exit 2
+    }
+    reduce_candidate "$2" "$3"
+    ;;
+  *)
+    printf 'usage: %s {inspect|reduce RETRIEVAL_SCORE SOURCE_DOCUMENT}\n' "$0" >&2
+    exit 2
+    ;;
+esac
diff --git a/docs/tab-qa-mock.md b/docs/tab-qa-mock.md
new file mode 100644
index 0000000..5144a44
--- /dev/null
+++ b/docs/tab-qa-mock.md
@@ -0,0 +1,84 @@
+# Saved-tab question-and-answer mock
+
+This is the first executable vertical slice of the ChatGPT-like text frontend.
+It is a console prompt, not the eventual phone UI, and it answers only from
+plain-text documents deliberately present below `~/reading`.
+
+The stages are explicit:
+
+1. `mock-token-i8-v1` tokenizes text into a 32-component, bounded 8-bit-count
+   test vector and selects one source line as an extractive answer.
+2. `ib-vector-index` stores one exact cosine index in the existing model-view
+   tree. Authoritative fixed-width text and its rebuildable Float32 cache are
+   two query paths over that index. Each query can record whether its dot
+   products used a GPU; the current C backend records `False` and `compute=cpu`.
+3. `mock-single-member-weighted-reducer-v1` is a one-member ensemble test
+   double. It runs three validations, records an aggregate score, and preserves
+   the candidate. This is the replaceable slot for voting, bagging, rank
+   aggregation, XGBoost, or another reducer; it does not claim to run XGBoost.
+4. `ib_tab_qa_null_render` is an identity post-processing step before the text
+   is returned.
+
+The bundled model is intentionally not described as an LLM. It is a tiny,
+queryable deterministic mock that exercises token, embedding, retrieval,
+model-output, reducer, and renderer boundaries without a model download.
+`IB_TAB_QA_MODEL_COMMAND` can name a later adapter implementing `inspect`,
+`embed`, and `answer`. `IB_TAB_QA_REDUCER_COMMAND` can replace the one-member
+reducer. The two pinned Hugging Face embedding manifests remain available for
+real model views; this mock writes `model-adapter.txt`, never a misleading
+`embedding-model.txt` manifest. A model name is bound to one exact adapter
+record, including the adapter command's SHA-256, so changed adapter code cannot
+silently reuse old vectors. An adapter with external model or vocabulary files
+must report their immutable hashes from `inspect` as part of the same record.
+
+## Filesystem boundaries
+
+Saved source text stays below `${IB_READING_DIR:-~/reading}`. The rebuildable
+index defaults to:
+
+```text
+${XDG_DATA_HOME:-~/.local/share}/ib/views/
+  organizing-the-information/vector-spaces/mock-token-i8-v1/reading/
+```
+
+Successful questions are appended as one directory per exchange below the
+separate requested folder:
+
+```text
+~/questions and answers about tabs that the user has visited/
+  <UTC-time>-<process>/
+    question.txt
+    model-candidate.txt
+    reduced-answer.txt
+    answer.txt
+    source.tsv
+    vector-query.tsv
+    vector-format.txt
+    reducer.tsv
+    indexing.tsv
+    model.tsv
+    reducer-model.tsv
+    reading-source.tsv
+    pipeline.tsv
+```
+
+The exchange preserves the raw model candidate, reduction evidence, selected
+source identity and content hash, upstream reading-source record, exact vector
+generation, adapter and reducer command hashes, vector execution report, and
+final response separately. It snapshots the selected document for processing
+and fails closed if those bytes differ from the indexed corpus record. The
+snapshot is temporary: canonical reading text is neither moved nor duplicated
+into the Q&A store. The command rejects a Q&A root equal to or nested with the
+reading root.
+
+## Run the mock
+
+```text
+make -C native/vector-index
+sh bin/ask_saved_pages.grease --index
+sh bin/ask_saved_pages.grease "What do feed-forward networks do to input space?"
+```
+
+Running the last command without a question displays `question>` and reads one
+line from the console. The index is reused until `--index` is run again; corpus
+change detection is deliberately left for the next slice.
diff --git a/docs/vector-index.md b/docs/vector-index.md
index d1eb99b..c26a2cb 100644
--- a/docs/vector-index.md
+++ b/docs/vector-index.md
@@ -36,6 +36,12 @@ document-id<TAB>0.8125
 
 `query` memory-maps the Float32 cache. `query-text` performs the same exact scan by parsing the readable file and works with the cache removed. `column` uses the fixed-width layout to print one coordinate across every ID. `compile-cache` atomically recreates the Float32 file from text. A later exact or approximate program can occupy the same process boundary without changing canonical browser state or callers that stream rows and queries.
 
+When `IB_VECTOR_QUERY_REPORT` names a file, either query command also writes a
+small execution report containing the compute device, storage path, metric,
+dimensions, and number of row dot products. The current portable C scan reports
+`dot-product-used-gpu=False`; a future accelerated backend must report its own
+execution rather than letting callers infer it.
+
 ## Files
 
 One model-specific view lives below the derived view root:
diff --git a/lib/tab_qa.grease b/lib/tab_qa.grease
new file mode 100644
index 0000000..de9c713
--- /dev/null
+++ b/lib/tab_qa.grease
@@ -0,0 +1,398 @@
+# Grease source. This is the first console-sized vertical slice of the
+# text-and-action workbench over material deliberately saved in ~/reading.
+
+ib_tab_qa_fail() {
+  printf 'tab Q&A: %s\n' "$1" >&2
+  return 1
+}
+
+ib_tab_qa_reading_root() {
+  if test -n "${IB_READING_DIR:-}"; then
+    printf '%s\n' "$IB_READING_DIR"
+  else
+    test -n "${HOME:-}" || return 1
+    printf '%s/reading\n' "$HOME"
+  fi
+}
+
+ib_tab_qa_root() {
+  if test -n "${IB_TAB_QA_DIR:-}"; then
+    printf '%s\n' "$IB_TAB_QA_DIR"
+  else
+    test -n "${HOME:-}" || return 1
+    printf '%s/questions and answers about tabs that the user has visited\n' "$HOME"
+  fi
+}
+
+ib_tab_qa_views_root() {
+  if test -n "${IB_VIEWS_DIR:-}"; then
+    printf '%s\n' "$IB_VIEWS_DIR"
+  else
+    test -n "${HOME:-}" || return 1
+    data_home=${XDG_DATA_HOME:-$HOME/.local/share}
+    printf '%s/ib/views\n' "$data_home"
+  fi
+}
+
+ib_tab_qa_model_command() {
+  printf '%s\n' "${IB_TAB_QA_MODEL_COMMAND:-$IB_TAB_QA_REPOSITORY_ROOT/bin/mock_tab_model.grease}"
+}
+
+ib_tab_qa_reducer_command() {
+  printf '%s\n' "${IB_TAB_QA_REDUCER_COMMAND:-$IB_TAB_QA_REPOSITORY_ROOT/bin/mock_tab_qa_reducer.grease}"
+}
+
+ib_tab_qa_vector_program() {
+  printf '%s\n' "${IB_VECTOR_INDEX_PROGRAM:-$IB_TAB_QA_REPOSITORY_ROOT/native/vector-index/ib-vector-index}"
+}
+
+ib_tab_qa_metadata_value() {
+  metadata_key=$1
+  sed -n "s/^${metadata_key}=//p" | sed -n '1p'
+}
+
+ib_tab_qa_sha256() {
+  command -v sha256sum >/dev/null 2>&1 || {
+    ib_tab_qa_fail 'sha256sum is unavailable'
+    return 1
+  }
+  checksum_line=$(sha256sum "$1") || return 1
+  checksum=${checksum_line%% *}
+  case "$checksum" in
+    ''|*[!0-9a-f]*) ib_tab_qa_fail "invalid SHA-256 for: $1"; return 1 ;;
+  esac
+  test "${#checksum}" -eq 64 || {
+    ib_tab_qa_fail "invalid SHA-256 for: $1"
+    return 1
+  }
+  printf '%s\n' "$checksum"
+}
+
+ib_tab_qa_safe_component() {
+  case "$1" in
+    ''|.|..|*[!A-Za-z0-9._-]*) return 1 ;;
+    *) return 0 ;;
+  esac
+}
+
+ib_tab_qa_safe_relative_document() {
+  relative_document=$1
+  tab_character=$(printf '\t')
+  case "$relative_document" in
+    ''|/*|.|..|../*|*/../*|*/..|*"$tab_character"*|*'
+'*) return 1 ;;
+    *) return 0 ;;
+  esac
+}
+
+ib_tab_qa_separate_roots() {
+  command -v realpath >/dev/null 2>&1 || return 1
+  first_root=$(realpath -m "$1") || return 1
+  second_root=$(realpath -m "$2") || return 1
+  case "$first_root/" in
+    "$second_root/"*) return 1 ;;
+  esac
+  case "$second_root/" in
+    "$first_root/"*) return 1 ;;
+  esac
+  return 0
+}
+
+ib_tab_qa_model_metadata() {
+  model_command=$(ib_tab_qa_model_command) || return 1
+  test -x "$model_command" || {
+    ib_tab_qa_fail "model is unavailable: $model_command"
+    return 1
+  }
+  model_report=$("$model_command" inspect) || return 1
+  model_command_sha256=$(ib_tab_qa_sha256 "$model_command") || return 1
+  printf '%s\nadapter-command-sha256=%s\n' "$model_report" "$model_command_sha256"
+}
+
+ib_tab_qa_reducer_metadata() {
+  reducer_command=$(ib_tab_qa_reducer_command) || return 1
+  test -x "$reducer_command" || {
+    ib_tab_qa_fail "reducer is unavailable: $reducer_command"
+    return 1
+  }
+  reducer_report=$("$reducer_command" inspect) || return 1
+  reducer_command_sha256=$(ib_tab_qa_sha256 "$reducer_command") || return 1
+  printf '%s\nreducer-command-sha256=%s\n' "$reducer_report" "$reducer_command_sha256"
+}
+
+ib_tab_qa_model_name() {
+  model_metadata=$(ib_tab_qa_model_metadata) || return 1
+  model_name=$(printf '%s\n' "$model_metadata" | ib_tab_qa_metadata_value model)
+  ib_tab_qa_safe_component "$model_name" || {
+    ib_tab_qa_fail "model reported an unsafe name: $model_name"
+    return 1
+  }
+  printf '%s\n' "$model_name"
+}
+
+ib_tab_qa_index_directory() {
+  views_root=$(ib_tab_qa_views_root) || return 1
+  model_name=$(ib_tab_qa_model_name) || return 1
+  printf '%s/organizing-the-information/vector-spaces/%s/reading\n' \
+    "$views_root" "$model_name"
+}
+
+ib_tab_qa_build_index() (
+  build_work=
+  cleanup() {
+    test -z "$build_work" || rm -rf "$build_work"
+  }
+  trap cleanup EXIT HUP INT TERM
+
+  reading_root=$(ib_tab_qa_reading_root) || return 1
+  views_root=$(ib_tab_qa_views_root) || return 1
+  index_directory=$(ib_tab_qa_index_directory) || return 1
+  model_command=$(ib_tab_qa_model_command) || return 1
+  vector_program=$(ib_tab_qa_vector_program) || return 1
+
+  test -d "$reading_root" || ib_tab_qa_fail "reading directory is missing: $reading_root" || return 1
+  test -x "$model_command" || ib_tab_qa_fail "model is unavailable: $model_command" || return 1
+  test -x "$vector_program" || ib_tab_qa_fail "vector backend is unavailable: $vector_program" || return 1
+  command -v find >/dev/null 2>&1 || ib_tab_qa_fail 'find is unavailable' || return 1
+  command -v sha256sum >/dev/null 2>&1 || ib_tab_qa_fail 'sha256sum is unavailable' || return 1
+
+  model_metadata=$(ib_tab_qa_model_metadata) || return 1
+  model_available=$(printf '%s\n' "$model_metadata" | ib_tab_qa_metadata_value available)
+  model_name=$(printf '%s\n' "$model_metadata" | ib_tab_qa_metadata_value model)
+  model_dimensions=$(printf '%s\n' "$model_metadata" | ib_tab_qa_metadata_value dimensions)
+  test "$model_available" = True || ib_tab_qa_fail "model did not report available: $model_command" || return 1
+  ib_tab_qa_safe_component "$model_name" || ib_tab_qa_fail "model reported an unsafe name: $model_name" || return 1
+  case "$model_dimensions" in
+    ''|*[!0-9]*) ib_tab_qa_fail 'model dimensions are not a positive integer' || return 1 ;;
+  esac
+  test "$model_dimensions" -gt 0 || ib_tab_qa_fail 'model dimensions must be positive' || return 1
+
+  sh "$IB_TAB_QA_REPOSITORY_ROOT/bin/ib_views.grease" init "$views_root"
+  model_view_directory=$(dirname "$index_directory")
+  test ! -L "$model_view_directory" || ib_tab_qa_fail "model view is a symbolic link: $model_view_directory" || return 1
+  mkdir -p "$model_view_directory"
+  adapter_record="$model_view_directory/model-adapter.txt"
+  if test -e "$adapter_record" || test -L "$adapter_record"; then
+    test -f "$adapter_record" && test ! -L "$adapter_record" || \
+      ib_tab_qa_fail "model adapter record is not a regular file: $adapter_record" || return 1
+    recorded_model_metadata=$(cat "$adapter_record")
+    test "$recorded_model_metadata" = "$model_metadata" || \
+      ib_tab_qa_fail "model name is already bound to different adapter facts: $model_name" || return 1
+  else
+    adapter_temporary=$(mktemp "$model_view_directory/.model-adapter.XXXXXX") || return 1
+    printf '%s\n' "$model_metadata" > "$adapter_temporary"
+    mv -T "$adapter_temporary" "$adapter_record"
+  fi
+
+  build_work=$(mktemp -d) || return 1
+  document_paths="$build_work/document-paths.txt"
+  vector_rows="$build_work/vector-rows.tsv"
+  corpus_rows="$build_work/corpus.tsv"
+  build_report="$build_work/build-report.txt"
+  : > "$vector_rows"
+  : > "$corpus_rows"
+  find "$reading_root" -type f -name document.txt -print | LC_ALL=C sort > "$document_paths"
+
+  document_count=0
+  while IFS= read -r document_path; do
+    test -n "$document_path" || continue
+    document_id=${document_path#"${reading_root%/}"/}
+    ib_tab_qa_safe_relative_document "$document_id" || {
+      ib_tab_qa_fail "unsafe reading document identity: $document_id"
+      return 1
+    }
+    test -s "$document_path" || ib_tab_qa_fail "reading document is empty: $document_id" || return 1
+    document_vector=$("$model_command" embed < "$document_path") || return 1
+    vector_dimensions=$(printf '%s\n' "$document_vector" | awk 'NR == 1 { print NF }')
+    test "$vector_dimensions" = "$model_dimensions" || {
+      ib_tab_qa_fail "model emitted $vector_dimensions dimensions, expected $model_dimensions"
+      return 1
+    }
+    document_sha256=$(ib_tab_qa_sha256 "$document_path") || return 1
+    document_bytes=$(wc -c < "$document_path" | tr -d '[:space:]')
+    printf '%s\t%s\n' "$document_id" "$document_vector" >> "$vector_rows"
+    printf '%s\t%s\t%s\n' "$document_id" "$document_sha256" "$document_bytes" >> "$corpus_rows"
+    document_count=$((document_count + 1))
+  done < "$document_paths"
+
+  test "$document_count" -gt 0 || ib_tab_qa_fail "no document.txt files exist below $reading_root" || return 1
+  "$vector_program" build "$index_directory" "$model_dimensions" cosine \
+    < "$vector_rows" > "$build_report"
+  "$vector_program" check "$index_directory" >/dev/null
+
+  corpus_temporary=$(mktemp "$index_directory/.corpus.XXXXXX") || return 1
+  cp "$corpus_rows" "$corpus_temporary"
+  mv -T "$corpus_temporary" "$index_directory/corpus.tsv"
+  indexing_temporary=$(mktemp "$index_directory/.indexing.XXXXXX") || return 1
+  printf '%s\n' \
+    'index-count=1' \
+    'index-1=flat-f32-exact/cosine' \
+    'query-path-count=2' \
+    'query-path-1=readable-fixed-width-text' \
+    'query-path-2=rebuildable-float32-cache' \
+    'collection=reading' \
+    "model=$model_name" \
+    "dimensions=$model_dimensions" \
+    "document-count=$document_count" > "$indexing_temporary"
+  mv -T "$indexing_temporary" "$index_directory/indexing.tsv"
+
+  sed -n '1,20p' "$build_report"
+  sed -n '1,20p' "$index_directory/indexing.tsv"
+)
+
+ib_tab_qa_ensure_index() {
+  index_directory=$(ib_tab_qa_index_directory) || return 1
+  adapter_record=$(dirname "$index_directory")/model-adapter.txt
+  current_model_metadata=$(ib_tab_qa_model_metadata) || return 1
+  if test -s "$index_directory/format.txt" &&
+     test -s "$index_directory/corpus.tsv" &&
+     test -s "$index_directory/indexing.tsv" &&
+     test -f "$adapter_record" && test ! -L "$adapter_record" &&
+     test "$(cat "$adapter_record")" = "$current_model_metadata"; then
+    return 0
+  fi
+  ib_tab_qa_build_index >/dev/null
+}
+
+ib_tab_qa_null_render() {
+  # This is a mock standing in for any further post-processing we want to do
+  # before returning the text to the user. Its current behavior is identity.
+  cat
+}
+
+ib_tab_qa_inspect() {
+  reading_root=$(ib_tab_qa_reading_root) || return 1
+  qa_root=$(ib_tab_qa_root) || return 1
+  views_root=$(ib_tab_qa_views_root) || return 1
+  index_directory=$(ib_tab_qa_index_directory) || return 1
+  pinned_manifest_count=$(find "$IB_TAB_QA_REPOSITORY_ROOT/models/embedding" -type f -name '*.model' | wc -l | tr -d '[:space:]')
+  printf '%s\n' \
+    'frontend=console-text-stub' \
+    "reading-root=$reading_root" \
+    "qa-root=$qa_root" \
+    "views-root=$views_root" \
+    "index-directory=$index_directory" \
+    "pinned-embedding-manifest-count=$pinned_manifest_count"
+  ib_tab_qa_model_metadata
+  ib_tab_qa_reducer_metadata
+  if test -s "$index_directory/format.txt"; then
+    printf 'index-available=True\n'
+    sed -n '/^index-count=/p; /^query-path-count=/p' "$index_directory/indexing.tsv"
+  else
+    printf 'index-available=False\n'
+  fi
+}
+
+ib_tab_qa_answer() (
+  answer_work=
+  exchange_partial=
+  cleanup() {
+    test -z "$answer_work" || rm -rf "$answer_work"
+    test -z "$exchange_partial" || rm -rf "$exchange_partial"
+  }
+  trap cleanup EXIT HUP INT TERM
+
+  question=$1
+  test -n "$question" || ib_tab_qa_fail 'question is empty' || return 1
+
+  reading_root=$(ib_tab_qa_reading_root) || return 1
+  qa_root=$(ib_tab_qa_root) || return 1
+  ib_tab_qa_separate_roots "$reading_root" "$qa_root" || {
+    ib_tab_qa_fail 'question-and-answer storage must be separate from the reading corpus'
+    return 1
+  }
+  ib_tab_qa_ensure_index || return 1
+  index_directory=$(ib_tab_qa_index_directory) || return 1
+  model_command=$(ib_tab_qa_model_command) || return 1
+  reducer_command=$(ib_tab_qa_reducer_command) || return 1
+  vector_program=$(ib_tab_qa_vector_program) || return 1
+  test -x "$reducer_command" || ib_tab_qa_fail "reducer is unavailable: $reducer_command" || return 1
+
+  answer_work=$(mktemp -d) || return 1
+  printf '%s\n' "$question" | "$model_command" embed > "$answer_work/question-vector.txt"
+  IB_VECTOR_QUERY_REPORT="$answer_work/vector-query.tsv" \
+    "$vector_program" query "$index_directory" 1 \
+    < "$answer_work/question-vector.txt" > "$answer_work/results.tsv"
+
+  result_line=$(sed -n '1p' "$answer_work/results.tsv")
+  test -n "$result_line" || ib_tab_qa_fail 'vector query returned no saved page' || return 1
+  source_id=$(printf '%s\n' "$result_line" | awk -F '\t' '{ print $1 }')
+  retrieval_score=$(printf '%s\n' "$result_line" | awk -F '\t' '{ print $2 }')
+  ib_tab_qa_safe_relative_document "$source_id" || ib_tab_qa_fail "vector index returned unsafe identity: $source_id" || return 1
+  source_document="${reading_root%/}/$source_id"
+  test -s "$source_document" || ib_tab_qa_fail "retrieved source is unavailable: $source_id" || return 1
+
+  corpus_record=$(awk -F '\t' -v wanted="$source_id" '
+    $1 == wanted { record = $0; matches++ }
+    END { if (matches == 1) print record; else exit 1 }
+  ' "$index_directory/corpus.tsv") || {
+    ib_tab_qa_fail "retrieved source has no unique index provenance: $source_id"
+    return 1
+  }
+  indexed_source_sha256=$(printf '%s\n' "$corpus_record" | awk -F '\t' '{ print $2 }')
+  indexed_source_bytes=$(printf '%s\n' "$corpus_record" | awk -F '\t' '{ print $3 }')
+  cp "$source_document" "$answer_work/source-document.txt"
+  answer_source_sha256=$(ib_tab_qa_sha256 "$answer_work/source-document.txt") || return 1
+  answer_source_bytes=$(wc -c < "$answer_work/source-document.txt" | tr -d '[:space:]')
+  if test "$answer_source_sha256" != "$indexed_source_sha256" ||
+     test "$answer_source_bytes" != "$indexed_source_bytes"; then
+    ib_tab_qa_fail "reading source changed since index build: $source_id (run --index)"
+    return 1
+  fi
+
+  reading_source_record=${source_document%/*}/source.tsv
+  reading_source_present=False
+  reading_source_sha256=
+  if test -f "$reading_source_record" && test ! -L "$reading_source_record"; then
+    cp "$reading_source_record" "$answer_work/reading-source.tsv"
+    reading_source_sha256=$(ib_tab_qa_sha256 "$answer_work/reading-source.tsv") || return 1
+    reading_source_present=True
+  fi
+
+  "$model_command" answer "$question" "$answer_work/source-document.txt" > "$answer_work/model-candidate.txt"
+  IB_TAB_QA_REDUCER_REPORT="$answer_work/reducer.tsv" \
+    "$reducer_command" reduce "$retrieval_score" "$answer_work/source-document.txt" \
+    < "$answer_work/model-candidate.txt" > "$answer_work/reduced-answer.txt"
+  ib_tab_qa_null_render < "$answer_work/reduced-answer.txt" > "$answer_work/answer.txt"
+  test -s "$answer_work/answer.txt" || ib_tab_qa_fail 'post-processing returned an empty response' || return 1
+
+  mkdir -p "$qa_root"
+  exchange_partial=$(mktemp -d "$qa_root/.partial.XXXXXX") || return 1
+  printf '%s\n' "$question" > "$exchange_partial/question.txt"
+  cp "$answer_work/model-candidate.txt" "$exchange_partial/model-candidate.txt"
+  cp "$answer_work/reduced-answer.txt" "$exchange_partial/reduced-answer.txt"
+  cp "$answer_work/answer.txt" "$exchange_partial/answer.txt"
+  cp "$answer_work/vector-query.tsv" "$exchange_partial/vector-query.tsv"
+  cp "$answer_work/reducer.tsv" "$exchange_partial/reducer.tsv"
+  cp "$index_directory/indexing.tsv" "$exchange_partial/indexing.tsv"
+  cp "$index_directory/format.txt" "$exchange_partial/vector-format.txt"
+  ib_tab_qa_model_metadata > "$exchange_partial/model.tsv"
+  ib_tab_qa_reducer_metadata > "$exchange_partial/reducer-model.tsv"
+  if test "$reading_source_present" = True; then
+    cp "$answer_work/reading-source.tsv" "$exchange_partial/reading-source.tsv"
+  fi
+  {
+    printf 'document-id\t%s\n' "$source_id"
+    printf 'retrieval-score\t%s\n' "$retrieval_score"
+    printf 'document-sha256\t%s\n' "$answer_source_sha256"
+    printf 'document-bytes\t%s\n' "$answer_source_bytes"
+    printf 'reading-source-present\t%s\n' "$reading_source_present"
+    printf 'reading-source-sha256\t%s\n' "$reading_source_sha256"
+  } > "$exchange_partial/source.tsv"
+  printf '%s\n' \
+    '1=vector-retrieval' \
+    '2=model-answer' \
+    '3=mock-ensemble-reducer' \
+    '4=null-identity-renderer' > "$exchange_partial/pipeline.tsv"
+
+  exchange_base=$(date -u '+%Y%m%dT%H%M%SZ')-$$
+  exchange_directory="$qa_root/$exchange_base"
+  exchange_suffix=0
+  while test -e "$exchange_directory"; do
+    exchange_suffix=$((exchange_suffix + 1))
+    exchange_directory="$qa_root/$exchange_base-$exchange_suffix"
+  done
+  mv "$exchange_partial" "$exchange_directory"
+  exchange_partial=
+  cat "$answer_work/answer.txt"
+)
diff --git a/native/vector-index/ib_vector_index.c b/native/vector-index/ib_vector_index.c
index 3a1c43c..413819e 100644
--- a/native/vector-index/ib_vector_index.c
+++ b/native/vector-index/ib_vector_index.c
@@ -834,6 +834,35 @@ static int dot_product_text(const unsigned char *stored, const float *query,
   return 1;
 }
 
+static int write_query_report(const char *path, const struct manifest *manifest,
+                              int use_text, size_t dot_products) {
+  if (path == NULL || path[0] == '\0') {
+    return 0;
+  }
+  FILE *file = fopen(path, "wb");
+  if (file == NULL) {
+    return fail_path("cannot open query report", path);
+  }
+  int bad = fprintf(file,
+                    "operation=exact-dot-product-scan\n"
+                    "compute=cpu\n"
+                    "dot-product-used-gpu=False\n"
+                    "storage=%s\n"
+                    "metric=%s\n"
+                    "dimensions=%zu\n"
+                    "dot-products=%zu\n",
+                    use_text ? "readable-text" : "float32-cache",
+                    metric_text(manifest->metric), manifest->dimensions,
+                    dot_products) < 0;
+  if (!bad && flush_file(file, path) != 0) {
+    bad = 1;
+  }
+  if (fclose(file) != 0) {
+    bad = 1;
+  }
+  return bad ? fail("cannot write query report") : 0;
+}
+
 static int match_before(float score, size_t row, const struct match *other) {
   return score > other->score || (score == other->score && row < other->row);
 }
@@ -876,6 +905,7 @@ static int query_index(const char *directory, const char *limit_text,
   int data_fd = -1;
   unsigned char *mapped = MAP_FAILED;
   int status = 1;
+  const char *query_report_path = getenv("IB_VECTOR_QUERY_REPORT");
 
   if (!parse_size(limit_text, &limit)) {
     return fail("result count must be a positive integer");
@@ -913,7 +943,7 @@ static int query_index(const char *directory, const char *limit_text,
   }
 
   if (limit == 0) {
-    status = 0;
+    status = write_query_report(query_report_path, &manifest, use_text, 0);
     goto cleanup;
   }
   matches = calloc(limit, sizeof(*matches));
@@ -980,7 +1010,8 @@ static int query_index(const char *directory, const char *limit_text,
   for (size_t i = 0; i < used; ++i) {
     printf("%s\t%.9g\n", matches[i].id, (double)matches[i].score);
   }
-  status = 0;
+  status = write_query_report(query_report_path, &manifest, use_text,
+                              manifest.count);
 
 cleanup:
   if (mapped != MAP_FAILED) {
diff --git a/tests/fixtures/reading/arxiv/1901.09021/document.txt b/tests/fixtures/reading/arxiv/1901.09021/document.txt
new file mode 100644
index 0000000..e449eb0
--- /dev/null
+++ b/tests/fixtures/reading/arxiv/1901.09021/document.txt
@@ -0,0 +1,3 @@
+Tiny color blocks
+Figure 1 shows tiny red, green, blue, and white color blocks.
+The figure is embedded in the PDF fixture used by the scientific reading path.
diff --git a/tests/fixtures/reading/arxiv/1901.09021/source.tsv b/tests/fixtures/reading/arxiv/1901.09021/source.tsv
new file mode 100644
index 0000000..725a695
--- /dev/null
+++ b/tests/fixtures/reading/arxiv/1901.09021/source.tsv
@@ -0,0 +1 @@
+pdf	1901.09021	fixture://arxiv_site/pdf/1901.09021
diff --git a/tests/fixtures/reading/arxiv/2203.11355/document.txt b/tests/fixtures/reading/arxiv/2203.11355/document.txt
new file mode 100644
index 0000000..54fb221
--- /dev/null
+++ b/tests/fixtures/reading/arxiv/2203.11355/document.txt
@@ -0,0 +1,5 @@
+Origami in N dimensions: How feed-forward networks manufacture linear separability
+Feed-forward networks fold input space into representations whose classes can be separated.
+The paper studies the geometry of the folding process.
+Figure 1. Linear regions along a one dimensional input.
+Activation space folding.
diff --git a/tests/fixtures/reading/arxiv/2203.11355/source.tsv b/tests/fixtures/reading/arxiv/2203.11355/source.tsv
new file mode 100644
index 0000000..4e2175c
--- /dev/null
+++ b/tests/fixtures/reading/arxiv/2203.11355/source.tsv
@@ -0,0 +1 @@
+html	2203.11355	fixture://arxiv_site/html/2203.11355
diff --git a/tests/test_mock_tab_model.grease b/tests/test_mock_tab_model.grease
new file mode 100755
index 0000000..0992f1f
--- /dev/null
+++ b/tests/test_mock_tab_model.grease
@@ -0,0 +1,34 @@
+#!/bin/sh
+set -eu
+
+repository_root=$(CDPATH= cd -- "$(dirname -- "$0")/.." && pwd)
+model="$repository_root/bin/mock_tab_model.grease"
+document="$repository_root/tests/fixtures/reading/arxiv/2203.11355/document.txt"
+
+metadata=$("$model" inspect)
+printf '%s\n' "$metadata" | grep -Fx 'model=mock-token-i8-v1'
+printf '%s\n' "$metadata" | grep -Fx 'available=True'
+printf '%s\n' "$metadata" | grep -Fx 'llm=False'
+printf '%s\n' "$metadata" | grep -Fx 'quantization=int8-counts'
+printf '%s\n' "$metadata" | grep -Fx 'dimensions=32'
+
+vector=$(printf '%s\n' 'feed-forward networks fold input space' | "$model" embed)
+printf '%s\n' "$vector" | awk '
+  NF != 32 { exit 1 }
+  {
+    nonzero = 0
+    for (field = 1; field <= NF; field++) {
+      if ($field !~ /^[0-9]+$/ || $field < 0 || $field > 127)
+        exit 1
+      if ($field > 0)
+        nonzero = 1
+    }
+    exit !nonzero
+  }
+'
+
+answer=$("$model" answer 'What do feed-forward networks do to input space?' "$document")
+printf '%s\n' "$answer" | grep -Fx \
+  'Feed-forward networks fold input space into representations whose classes can be separated.'
+
+printf 'mock tab model tests: ok\n'
diff --git a/tests/test_tab_qa_pipeline.grease b/tests/test_tab_qa_pipeline.grease
new file mode 100755
index 0000000..238bc26
--- /dev/null
+++ b/tests/test_tab_qa_pipeline.grease
@@ -0,0 +1,171 @@
+#!/bin/sh
+set -eu
+
+repository_root=$(CDPATH= cd -- "$(dirname -- "$0")/.." && pwd)
+work_directory=$(mktemp -d)
+cleanup() {
+  rm -rf "$work_directory"
+}
+trap cleanup EXIT HUP INT TERM
+
+export HOME="$work_directory/home"
+export IB_READING_DIR="$work_directory/reading"
+export IB_TAB_QA_DIR="$work_directory/questions and answers about tabs that the user has visited"
+export IB_VIEWS_DIR="$work_directory/views"
+export IB_VECTOR_INDEX_PROGRAM="$repository_root/native/vector-index/ib-vector-index"
+index_directory="$IB_VIEWS_DIR/organizing-the-information/vector-spaces/mock-token-i8-v1/reading"
+model_view_directory=$(dirname "$index_directory")
+mkdir -p "$HOME" "$IB_READING_DIR"
+cp -R "$repository_root/tests/fixtures/reading/." "$IB_READING_DIR/"
+
+make -C "$repository_root/native/vector-index" >/dev/null
+
+document_count=$(find "$IB_READING_DIR" -type f -name document.txt | wc -l | tr -d '[:space:]')
+test "$document_count" = 2
+find "$IB_READING_DIR" -type f -name document.txt -exec test -s {} \;
+grep -F 'Origami in N dimensions' \
+  "$repository_root/tests/fixtures/arxiv_site/html/2203.11355" >/dev/null
+grep -aF 'Figure 1. Tiny color blocks' \
+  "$repository_root/tests/fixtures/arxiv_site/pdf/1901.09021" >/dev/null
+grep -F 'Feed-forward networks fold input space' \
+  "$IB_READING_DIR/arxiv/2203.11355/document.txt" >/dev/null
+grep -F 'tiny red, green, blue, and white color blocks' \
+  "$IB_READING_DIR/arxiv/1901.09021/document.txt" >/dev/null
+awk -F '\t' 'NR == 1 && $1 == "html" && $3 == "fixture://arxiv_site/html/2203.11355" { found = 1 } END { exit !found }' \
+  "$IB_READING_DIR/arxiv/2203.11355/source.tsv"
+awk -F '\t' 'NR == 1 && $1 == "pdf" && $3 == "fixture://arxiv_site/pdf/1901.09021" { found = 1 } END { exit !found }' \
+  "$IB_READING_DIR/arxiv/1901.09021/source.tsv"
+
+inspect_before=$(sh "$repository_root/bin/ask_saved_pages.grease" --inspect)
+printf '%s\n' "$inspect_before" | grep -Fx 'frontend=console-text-stub'
+pinned_manifest_count=$(printf '%s\n' "$inspect_before" | sed -n 's/^pinned-embedding-manifest-count=//p')
+test "$pinned_manifest_count" -ge 1
+printf '%s\n' "$inspect_before" | grep -Fx 'available=True'
+printf '%s\n' "$inspect_before" | grep -Fx 'llm=False'
+printf '%s\n' "$inspect_before" | grep -Fx 'ensemble=single-member-test-double'
+printf '%s\n' "$inspect_before" | grep -Fx 'index-available=False'
+
+sh "$repository_root/bin/ask_saved_pages.grease" --index > "$work_directory/index-build.txt"
+grep -Fx 'build=ok' "$work_directory/index-build.txt"
+grep -Fx 'count=2' "$work_directory/index-build.txt"
+grep -Fx 'index-count=1' "$work_directory/index-build.txt"
+grep -Fx 'query-path-count=2' "$work_directory/index-build.txt"
+grep -Fx 'query-path-1=readable-fixed-width-text' "$work_directory/index-build.txt"
+grep -Fx 'query-path-2=rebuildable-float32-cache' "$work_directory/index-build.txt"
+grep -Fx 'document-count=2' "$work_directory/index-build.txt"
+test -s "$index_directory/format.txt"
+test -s "$index_directory/corpus.tsv"
+test -s "$model_view_directory/model-adapter.txt"
+grep -E '^adapter-command-sha256=[0-9a-f]{64}$' "$model_view_directory/model-adapter.txt" >/dev/null
+test ! -e "$model_view_directory/embedding-model.txt"
+test "$(wc -l < "$index_directory/corpus.tsv" | tr -d '[:space:]')" = 2
+vectors_text=$(sed -n 's/^vectors_text //p' "$index_directory/format.txt")
+vectors_cache=$(sed -n 's/^vectors_cache //p' "$index_directory/format.txt")
+test -s "$index_directory/$vectors_text"
+test -s "$index_directory/$vectors_cache"
+"$IB_VECTOR_INDEX_PROGRAM" check "$index_directory" >/dev/null
+inspect_after=$(sh "$repository_root/bin/ask_saved_pages.grease" --inspect)
+printf '%s\n' "$inspect_after" | grep -Fx 'index-available=True'
+printf '%s\n' "$inspect_after" | grep -Fx 'index-count=1'
+printf '%s\n' "$inspect_after" | grep -Fx 'query-path-count=2'
+
+changed_model="$work_directory/changed-model.grease"
+cp "$repository_root/bin/mock_tab_model.grease" "$changed_model"
+printf '%s\n' '# behavior-bearing adapter bytes changed' >> "$changed_model"
+chmod +x "$changed_model"
+if IB_TAB_QA_MODEL_COMMAND="$changed_model" \
+  sh "$repository_root/bin/ask_saved_pages.grease" --index \
+  > "$work_directory/changed-model.txt" 2>&1; then
+  printf 'changed adapter code silently reused the model name\n' >&2
+  exit 1
+fi
+grep -F 'model name is already bound to different adapter facts' \
+  "$work_directory/changed-model.txt" >/dev/null
+
+question='What do feed-forward networks do to input space?'
+printf '%s\n' "$question" | "$repository_root/bin/mock_tab_model.grease" embed \
+  > "$work_directory/question-vector.txt"
+IB_VECTOR_QUERY_REPORT="$work_directory/cached-query.tsv" \
+  "$IB_VECTOR_INDEX_PROGRAM" query "$index_directory" 2 \
+  < "$work_directory/question-vector.txt" > "$work_directory/cached-results.tsv"
+IB_VECTOR_QUERY_REPORT="$work_directory/readable-query.tsv" \
+  "$IB_VECTOR_INDEX_PROGRAM" query-text "$index_directory" 2 \
+  < "$work_directory/question-vector.txt" > "$work_directory/readable-results.tsv"
+cmp "$work_directory/cached-results.tsv" "$work_directory/readable-results.tsv"
+grep -Fx 'dot-product-used-gpu=False' "$work_directory/cached-query.tsv"
+grep -Fx 'compute=cpu' "$work_directory/cached-query.tsv"
+grep -Fx 'storage=float32-cache' "$work_directory/cached-query.tsv"
+grep -Fx 'dot-products=2' "$work_directory/cached-query.tsv"
+grep -Fx 'dot-product-used-gpu=False' "$work_directory/readable-query.tsv"
+grep -Fx 'storage=readable-text' "$work_directory/readable-query.tsv"
+
+response=$(printf '%s\n' "$question" | \
+  sh "$repository_root/bin/ask_saved_pages.grease" 2> "$work_directory/prompt.txt")
+grep -Fx 'question> ' "$work_directory/prompt.txt"
+test -n "$response"
+printf '%s\n' "$response" | grep -Fx \
+  'Feed-forward networks fold input space into representations whose classes can be separated.'
+
+test "$IB_TAB_QA_DIR" != "$IB_READING_DIR"
+exchange_count=$(find "$IB_TAB_QA_DIR" -mindepth 1 -maxdepth 1 -type d ! -name '.partial.*' | wc -l | tr -d '[:space:]')
+test "$exchange_count" = 1
+exchange_directory=$(find "$IB_TAB_QA_DIR" -mindepth 1 -maxdepth 1 -type d ! -name '.partial.*' | sed -n '1p')
+test -s "$exchange_directory/question.txt"
+test -s "$exchange_directory/answer.txt"
+test -s "$exchange_directory/model-candidate.txt"
+test -s "$exchange_directory/reduced-answer.txt"
+test -s "$exchange_directory/source.tsv"
+test -s "$exchange_directory/vector-format.txt"
+test -s "$exchange_directory/reading-source.tsv"
+grep -Fx 'dot-product-used-gpu=False' "$exchange_directory/vector-query.tsv"
+grep -Fx 'compute=cpu' "$exchange_directory/vector-query.tsv"
+grep -Fx 'storage=float32-cache' "$exchange_directory/vector-query.tsv"
+grep -Fx 'dot-products=2' "$exchange_directory/vector-query.tsv"
+grep -Fx 'reducer=mock-single-member-weighted-reducer-v1' "$exchange_directory/reducer.tsv"
+grep -Fx 'ensemble-stage-ran=True' "$exchange_directory/reducer.tsv"
+grep -Fx 'member-count=1' "$exchange_directory/reducer.tsv"
+grep -Fx 'checks-run=3' "$exchange_directory/reducer.tsv"
+grep -Fx 'candidate-nonempty=True' "$exchange_directory/reducer.tsv"
+grep -E '^aggregate-score=[-+0-9.eE]+$' "$exchange_directory/reducer.tsv" >/dev/null
+awk -F '\t' '$1 == "document-id" && $2 == "arxiv/2203.11355/document.txt" { found = 1 } END { exit !found }' \
+  "$exchange_directory/source.tsv"
+awk -F '\t' '$1 == "document-sha256" && $2 ~ /^[0-9a-f]{64}$/ { found = 1 } END { exit !found }' \
+  "$exchange_directory/source.tsv"
+awk -F '\t' '$1 == "reading-source-present" && $2 == "True" { found = 1 } END { exit !found }' \
+  "$exchange_directory/source.tsv"
+awk -F '\t' '$1 == "reading-source-sha256" && $2 ~ /^[0-9a-f]{64}$/ { found = 1 } END { exit !found }' \
+  "$exchange_directory/source.tsv"
+cmp "$exchange_directory/reading-source.tsv" "$IB_READING_DIR/arxiv/2203.11355/source.tsv"
+grep -E '^adapter-command-sha256=[0-9a-f]{64}$' "$exchange_directory/model.tsv" >/dev/null
+grep -E '^reducer-command-sha256=[0-9a-f]{64}$' "$exchange_directory/reducer-model.tsv" >/dev/null
+cmp "$exchange_directory/reduced-answer.txt" "$exchange_directory/answer.txt"
+grep -Fx '4=null-identity-renderer' "$exchange_directory/pipeline.tsv"
+grep -Fx 'index-count=1' "$exchange_directory/indexing.tsv"
+test "$(find "$IB_READING_DIR" -type f -name document.txt | wc -l | tr -d '[:space:]')" = 2
+
+printf '%s\n' 'changed after indexing' >> "$IB_READING_DIR/arxiv/2203.11355/document.txt"
+if sh "$repository_root/bin/ask_saved_pages.grease" "$question" \
+  > "$work_directory/stale-source.txt" 2>&1; then
+  printf 'changed reading source was unexpectedly accepted\n' >&2
+  exit 1
+fi
+grep -F 'reading source changed since index build' "$work_directory/stale-source.txt" >/dev/null
+test "$(find "$IB_TAB_QA_DIR" -mindepth 1 -maxdepth 1 -type d ! -name '.partial.*' | wc -l | tr -d '[:space:]')" = 1
+
+if IB_TAB_QA_DIR="$IB_READING_DIR/qa" \
+  sh "$repository_root/bin/ask_saved_pages.grease" "$question" \
+  > "$work_directory/nested-root.txt" 2>&1; then
+  printf 'nested Q&A root was unexpectedly accepted\n' >&2
+  exit 1
+fi
+grep -F 'question-and-answer storage must be separate' "$work_directory/nested-root.txt" >/dev/null
+
+if IB_TAB_QA_DIR="$IB_READING_DIR/../reading/qa" \
+  sh "$repository_root/bin/ask_saved_pages.grease" "$question" \
+  > "$work_directory/normalized-nested-root.txt" 2>&1; then
+  printf 'normalized nested Q&A root was unexpectedly accepted\n' >&2
+  exit 1
+fi
+grep -F 'question-and-answer storage must be separate' "$work_directory/normalized-nested-root.txt" >/dev/null
+
+printf 'tab Q&A pipeline tests: ok\n'
diff --git a/tests/vector-index-smoke.sh b/tests/vector-index-smoke.sh
index dad527c..c01a17c 100644
--- a/tests/vector-index-smoke.sh
+++ b/tests/vector-index-smoke.sh
@@ -24,13 +24,23 @@ grep -Fx 'check=ok' "$temporary/check.txt"
 grep -Fx 'text_slot_bytes=16' "$temporary/check.txt"
 
 printf '%s\n' '0.9 0.1 0' |
+  IB_VECTOR_QUERY_REPORT="$temporary/cache-query-report.txt" \
   "$program" query "$index" 2 > "$temporary/results.txt"
 sed -n '1s/	.*//p' "$temporary/results.txt" | grep -Fx 'book-page'
 sed -n '2s/	.*//p' "$temporary/results.txt" | grep -Fx 'mixed-page'
+grep -Fx 'operation=exact-dot-product-scan' "$temporary/cache-query-report.txt"
+grep -Fx 'compute=cpu' "$temporary/cache-query-report.txt"
+grep -Fx 'dot-product-used-gpu=False' "$temporary/cache-query-report.txt"
+grep -Fx 'storage=float32-cache' "$temporary/cache-query-report.txt"
+grep -Fx 'dimensions=3' "$temporary/cache-query-report.txt"
+grep -Fx 'dot-products=3' "$temporary/cache-query-report.txt"
 
 printf '%s\n' '0.9 0.1 0' |
+  IB_VECTOR_QUERY_REPORT="$temporary/text-query-report.txt" \
   "$program" query-text "$index" 2 > "$temporary/text-results.txt"
 cmp "$temporary/results.txt" "$temporary/text-results.txt"
+grep -Fx 'dot-product-used-gpu=False' "$temporary/text-query-report.txt"
+grep -Fx 'storage=readable-text' "$temporary/text-query-report.txt"
 
 "$program" column "$index" 1 > "$temporary/first-coordinate.txt"
 grep -Fx 'book-page	+1.00000000e+00' "$temporary/first-coordinate.txt"