diff --git a/README.md b/README.md
index b93184b..af146da 100644
--- a/README.md
+++ b/README.md
@@ -45,9 +45,13 @@ default.
 
 `--words-from <repo>` lifts the words a repo already has back into the
 words map by structure, so a rebuild keeps hand-edited wording and
-adds only the new slots; `--words <json>` overrides slots by page;
+adds only the new slots. The lift is by position, so it holds for a
+rebuild of the same shape and not across a restructure: on uhhm.no it
+put the old front door's three headings on three new cards. `--words
+<json>` overrides slots by page and may repeat, each file layered over
+the last (the words a build used, then a round of hand changes);
 `words.json` in the output is the words as used. See
-`runs/tomtervel-invites-2026-09-23`.
+`runs/tomtervel-invites-2026-09-23` and `runs/uhhm-2026-09-23`.
 
 | Same contractor, same local model (nemotron 30B-A3B on ergo) | Free-form `generate` | `build` |
 |---|---|---|
diff --git a/src/build.rs b/src/build.rs
index 9cc5e65..5b6af8d 100644
--- a/src/build.rs
+++ b/src/build.rs
@@ -833,7 +833,11 @@ fn slots_in(value: &Value, key: &str, parent: &str) -> Value {
                 (_, "question") => "the one question this page asks its reader".to_string(),
                 (_, "heading" | "next_heading") => "a heading, at most eight words, saying what the reader gets".to_string(),
                 (_, "description" | "page_description" | "next_description") => "one or two short sentences".to_string(),
-                (_, "button" | "back" | "confirm") => "a button, one to three words, saying what pressing it does".to_string(),
+                (_, "button" | "back") => "a button, one to three words, saying what pressing it does".to_string(),
+                // One slot serves every list on the desk, so it cannot
+                // name any one of them: a model once wrote "Send invite"
+                // under the cases list.
+                (_, "confirm") => "the one button under every list on this desk, confirming a move the person has chosen; one word, such as Confirm".to_string(),
                 (_, "encouragement") => "one reassuring sentence: what happens with what they send, or how little it takes; or empty".to_string(),
                 (_, "icon") => "an icon name from the list at the end, the one that fits this best; or empty".to_string(),
                 (_, "for_whom") => "a few words naming who this is for, addressed to them; or empty".to_string(),
@@ -1296,7 +1300,7 @@ fn words_prompt(plan: &Plan, path: &str, fallback: &Value) -> String {
 
 pub fn run(argv: &[String]) -> anyhow::Result<()> {
     let value = |flag: &str| argv.iter().position(|a| a == flag).and_then(|i| argv.get(i + 1)).cloned();
-    let usage = "usage: portal-trainer build --plan <plan.yaml> --out <dir> [--words-from <existing repo>] [--words <overrides.json>] [--llm 'cmd'] [--lint question_lint]";
+    let usage = "usage: portal-trainer build --plan <plan.yaml> --out <dir> [--words-from <existing repo>] [--words <words.json>]... [--llm 'cmd'] [--lint question_lint]";
     let plan_path = value("--plan").ok_or_else(|| anyhow!(usage))?;
     let out = std::path::PathBuf::from(value("--out").ok_or_else(|| anyhow!(usage))?);
     let plan: Plan = serde_yaml::from_str(&std::fs::read_to_string(&plan_path).with_context(|| format!("reading {plan_path}"))?)
@@ -1313,8 +1317,13 @@ pub fn run(argv: &[String]) -> anyhow::Result<()> {
         Some(repo) => lift_words(&plan, Path::new(&repo))?,
         None => fallback_words(&plan),
     };
-    if let Some(path) = value("--words") {
-        let given: BTreeMap<String, Value> = serde_json::from_str(&std::fs::read_to_string(&path).with_context(|| format!("reading {path}"))?)
+    // `--words` may repeat: the words a previous build used, then a
+    // round of hand overrides on top, in the order given. Each is
+    // merged key by key over what is there, so a file names only the
+    // slots it changes.
+    let words_files: Vec<&String> = argv.iter().enumerate().filter(|(_, a)| *a == "--words").filter_map(|(i, _)| argv.get(i + 1)).collect();
+    for path in words_files {
+        let given: BTreeMap<String, Value> = serde_json::from_str(&std::fs::read_to_string(path).with_context(|| format!("reading {path}"))?)
             .with_context(|| format!("parsing {path}"))?;
         for (page, v) in given {
             match words.get(&page) {