diff --git a/CHANGELOG.md b/CHANGELOG.md
index f6928ba..0d787bc 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -185,6 +185,19 @@ different event from one that moved because it was wrong.
 
 ### Documentation
 
+- A new page, [Your own data](docs/datasets.md), gives the row format, what
+  the loader refuses and why, and the commands a user needs next: a local
+  checkpoint with its pinned revision, the cascade's two costs, and
+  `plumbline report` for runs that already happened (#61). A test holds its
+  example rows to the loader.
+- The README's hosted-vendor command used `--max-cases 40` against 105 rows,
+  which refuses rather than truncates, so it sent nothing (#29); it uses
+  `--limit 40`, and `--max-cases` says in its help that it is a guard.
+- The README said `pip install plumbline` "will not work"; it installs an
+  unrelated project of the same name (#60). It now says so and gives pip
+  commands that install this one, and the missing-extra error no longer points
+  at the PyPI package.
+
 - `docs/example-report.md` is now checked line for line against its recorded
   command on every site build, not only its ECE line, and the README says that
   instead of calling it "unedited".
diff --git a/README.md b/README.md
index 825c5f1..e5a8e44 100644
--- a/README.md
+++ b/README.md
@@ -109,8 +109,16 @@ That refusal is the product.
 An older Python gives a resolver error rather than a clear message, so check
 with `python --version` first.
 
-**plumbline is not on PyPI.** `pip install plumbline` will not work. Clone the
-repository; that is the intended install path for v0.1.
+**plumbline is not on PyPI, and `pip install plumbline` installs something
+else.** The name on PyPI belongs to an unrelated project, so that command
+succeeds and gives you the wrong tool. Clone the repository, which is the
+intended install path for v0.1. If you use pip rather than uv, install from the
+repository itself:
+
+```
+pip install "plumbline @ git+https://github.com/TMHSDigital/plumbline"
+pip install "plumbline[local] @ git+https://github.com/TMHSDigital/plumbline"   # with the local extra
+```
 
 Nothing in this first section needs an API key or spends anything.
 
@@ -206,7 +214,7 @@ $env:TYPESAFE_API_KEY = "your-key-here"
 uv run plumbline run datasets/public/jevbench-hard.jsonl `
     --adapter typesafe_wire --model jev-latest --format jevbench `
     --results results --report results/report.md `
-    --max-cases 40 --pricing my-pricing.json
+    --limit 40 --pricing my-pricing.json
 ```
 
 </details>
@@ -220,7 +228,7 @@ export TYPESAFE_API_KEY="your-key-here"
 uv run plumbline run datasets/public/jevbench-hard.jsonl \
     --adapter typesafe_wire --model jev-latest --format jevbench \
     --results results --report results/report.md \
-    --max-cases 40 --pricing my-pricing.json
+    --limit 40 --pricing my-pricing.json
 ```
 
 </details>
@@ -231,6 +239,9 @@ Without a pricing table the run still works; cost reports as unpriced, and
 
 Your own data goes in `datasets/private/`, which is gitignored, and that is the
 only path on which the recalibration numbers mean anything.
+[Your own data](docs/datasets.md) gives the row format, what is refused and why,
+and the commands to run next: a local checkpoint, the cascade's two costs, and
+`plumbline report` for runs that already happened.
 
 ## Example report
 
diff --git a/docs/PLAN.md b/docs/PLAN.md
index c57c01f..38b1816 100644
--- a/docs/PLAN.md
+++ b/docs/PLAN.md
@@ -197,7 +197,9 @@ defensible merely because projects usually have one.
 - **`CITATION.cff`.** Nobody has cited this. A citation file asserting how to
   cite work nobody has referenced is a claim about its significance rather than
   a service to a reader. Revisit if someone references the METHODOLOGY results.
-- **PyPI publishing.** Premature. It commits the project to a name and to a
+- **PyPI publishing.** Premature, and the name is taken: `plumbline` on PyPI is
+  an unrelated project, so publishing needs a different distribution name
+  first. It commits the project to a name and to a
   release cadence before the API has settled, and the API is explicitly not
   stable before v0.2. The README says cloning is the install path, which is
   honest and costs a reader one command. Revisit when the CLI flags stop
diff --git a/docs/datasets.md b/docs/datasets.md
new file mode 100644
index 0000000..debe0db
--- /dev/null
+++ b/docs/datasets.md
@@ -0,0 +1,114 @@
+# Your own data
+
+plumbline measures a model on your labeled rows, so this is the file format
+you write them in, and the commands you run next. Put your file anywhere; the
+repository's [`datasets/private/`](../datasets/private) directory is gitignored
+for exactly this, so a clone never commits it.
+
+## The format
+
+One JSON object per line (JSONL), UTF-8. Blank lines are skipped. Every other
+line is one case.
+
+| field | required | what it is |
+|---|---|---|
+| `id` | yes | A non-empty string, unique in the file. It names the row in the artifact. |
+| `text` | yes | A non-empty string: what the model is shown. |
+| `labels` | yes | A list of at least two distinct strings: the options it chooses between. |
+| `gold_label` | yes | The correct option. It must be one of `labels`. |
+| `question_type` | no | `choice` (the default), `noul`, or `score`. See below. |
+| `label_descriptions` | no | An object mapping an option to a sentence describing it. v0.1 loads these but does not yet send them to any adapter ([#39](https://github.com/TMHSDigital/plumbline/issues/39)). |
+
+`question_type` says what the row actually asks, and plumbline asks it that way:
+
+- `choice`: pick one of the options. Most classification rows are this.
+- `noul`: a yes/no question. The options must be a yes/no pair (`yes`/`no` or
+  `true`/`false`), because which option is the yes is a fact about your data,
+  not something to guess. A transport that has a native yes/no question asks it
+  as one, and gets back one probability rather than a distribution.
+- `score`: an ordinal level, such as 0 to 3. v0.1 loads these rows and excludes
+  them from every figure, because ordering is lost if levels are scored as
+  unordered options. The load summary says how many there were.
+
+## An example
+
+```jsonl
+{"id": "t-1", "text": "My card was charged twice for one order.", "labels": ["billing", "shipping", "returns", "other"], "gold_label": "billing"}
+{"id": "t-2", "text": "The parcel says delivered but it is not here.", "labels": ["billing", "shipping", "returns", "other"], "gold_label": "shipping"}
+{"id": "t-3", "text": "Is this order eligible for a refund?", "labels": ["yes", "no"], "gold_label": "yes", "question_type": "noul"}
+{"id": "t-4", "text": "How urgent is this complaint, 0 to 3?", "labels": ["0", "1", "2", "3"], "gold_label": "2", "question_type": "score"}
+{"id": "t-5", "text": "Where is my refund?", "labels": ["billing", "returns"], "gold_label": "returns", "label_descriptions": {"billing": "charges and invoices", "returns": "sending an item back, and its refund"}}
+```
+
+## What is refused, and why
+
+A row that cannot be scored honestly is refused with its line number, and the
+rest of the file still runs. `--strict` refuses the whole run instead.
+
+- A missing required field, an empty `id` or `text`, or `labels` that is not a
+  list of at least two distinct entries.
+- A `gold_label` that is not one of the row's own `labels`. Scoring it would
+  mark every model wrong on that row, which reads as a model failure and is a
+  data error.
+- A `question_type` other than the three above. An unknown type is not assumed
+  to be a choice.
+- An `id` already used earlier in the file.
+- A line that is not a JSON object.
+
+A file with no rows at all, or a path that does not exist, is an error rather
+than an empty run.
+
+## Running it
+
+The mock needs nothing and spends nothing, so start there to check the file:
+
+```
+uv run plumbline run my-data.jsonl --adapter mock --results results --report results/report.md
+```
+
+A hosted vendor needs its key in the environment and, for a cost column, a
+pricing table you filled in (see the README). `--limit` runs only the first N
+cases; `--max-cases` and `--max-cost-usd` refuse the run instead of truncating
+it, so they are guards rather than ways to run less:
+
+```
+uv run plumbline run my-data.jsonl --adapter typesafe_wire --model jev-latest \
+    --limit 40 --max-cost-usd 0.50 --pricing my-pricing.json \
+    --results results --report results/report.md
+```
+
+A local checkpoint needs the `local` extra (`uv sync --extra local`), a model
+id, and the commit it is pinned to, as 40 hex characters. A branch name or a tag
+can move, and everything measured would then be attributed to other weights:
+
+```
+uv run plumbline run my-data.jsonl --adapter local_logits \
+    --model Qwen/Qwen2.5-0.5B-Instruct --revision 7ae557604adf67be50417f59c2c2f167def9a775 \
+    --results results --report results/report.md
+```
+
+## The cascade needs two numbers only you know
+
+Where to set a threshold depends on what one escalation to the expensive path
+costs you and what one wrong answer costs you. plumbline never defaults either,
+because a made-up default would decide the threshold. Pass both, in USD:
+
+```
+uv run plumbline run my-data.jsonl --adapter mock --escalation-cost 0.02 --error-cost 1.00 \
+    --results results --report results/report.md
+```
+
+The threshold is chosen on half of the scored rows and judged on the other half,
+so a threshold needs at least 400 scored rows; below that the report says so
+instead of printing one.
+
+## Reports from runs that already happened
+
+Every run writes an artifact to `--results`. `plumbline report` renders one
+document from one or more of them, so a finished run is never repeated to get a
+report, or to try different cascade costs:
+
+```
+uv run plumbline report results/*.json --out results/report.md \
+    --escalation-cost 0.02 --error-cost 1.00
+```
diff --git a/scripts/build_site.py b/scripts/build_site.py
index 5e5414b..9579a08 100644
--- a/scripts/build_site.py
+++ b/scripts/build_site.py
@@ -92,6 +92,13 @@ class Doc:
         "What plumbline is, how to run it, and what it does not do.",
         USING,
     ),
+    Doc(
+        "docs/datasets.md",
+        "your-data",
+        "Your own data",
+        "The row format, what is refused and why, and the commands to run next.",
+        USING,
+    ),
     Doc(
         "METHODOLOGY.md",
         "methodology",
diff --git a/src/plumbline/adapters/local_logits.py b/src/plumbline/adapters/local_logits.py
index d36f3a1..9cba931 100644
--- a/src/plumbline/adapters/local_logits.py
+++ b/src/plumbline/adapters/local_logits.py
@@ -311,7 +311,10 @@ def __init__(self, *, model_id: str, revision: str, device: str = "cpu") -> None
         except ImportError as missing:  # pragma: no cover - exercised by installing extras
             raise PlumblineError(
                 "the local_logits arm needs torch and transformers, which are an optional "
-                "dependency. Install them with: pip install 'plumbline[local]'"
+                "dependency. Install them with: uv sync --extra local (with pip, install "
+                "from the repository: pip install "
+                '"plumbline[local] @ git+https://github.com/TMHSDigital/plumbline"; the '
+                "plumbline on PyPI is an unrelated project)"
             ) from missing
 
         self._torch = torch
diff --git a/src/plumbline/cli.py b/src/plumbline/cli.py
index b5fdb87..4fd370b 100644
--- a/src/plumbline/cli.py
+++ b/src/plumbline/cli.py
@@ -57,7 +57,14 @@ def run(
     workers: Annotated[int, typer.Option(min=1, help="Concurrent requests.")] = 8,
     cache_dir: Annotated[Path | None, typer.Option("--cache", help="Cache directory.")] = None,
     max_cost_usd: Annotated[float | None, typer.Option(help="Abort above this.")] = None,
-    max_cases: Annotated[int | None, typer.Option(min=1, help="Abort above this many.")] = None,
+    max_cases: Annotated[
+        int | None,
+        typer.Option(
+            min=1,
+            help="Refuse the run if it covers more cases than this. A guard, not a "
+            "truncation: use --limit to run fewer.",
+        ),
+    ] = None,
     semantics: Annotated[
         str | None, typer.Option(help="Override probability_semantics (mock only).")
     ] = None,
diff --git a/tests/test_datasets.py b/tests/test_datasets.py
index d4213c7..5616c5e 100644
--- a/tests/test_datasets.py
+++ b/tests/test_datasets.py
@@ -322,3 +322,22 @@ def test_an_unknown_question_type_is_refused_rather_than_assumed_to_be_a_choice(
 
     assert report.cases == ()
     assert "question_type" in report.refusals[0].reason
+
+
+def test_the_example_in_the_dataset_docs_loads_as_documented(tmp_path) -> None:
+    """docs/datasets.md shows the format; the format it shows must be the one the loader reads."""
+    import re
+    from pathlib import Path
+
+    doc = Path(__file__).resolve().parent.parent / "docs" / "datasets.md"
+    block = re.search(r"```jsonl\n(.*?)```", doc.read_text(encoding="utf-8"), re.S)
+    assert block is not None, "docs/datasets.md has no jsonl example"
+    path = tmp_path / "example.jsonl"
+    path.write_text(block.group(1), encoding="utf-8")
+
+    report = loader.load_jsonl(path)
+
+    assert not report.refusals
+    kinds = sorted(case.question_type for case in report.cases)
+    assert kinds == ["choice", "choice", "choice", "noul", "score"]
+    assert len(report.scoreable) == 4  # the score row loads and is held back