diff --git a/crates/automation/README.md b/crates/automation/README.md
index 7a9de516c0..92fd2775c9 100644
--- a/crates/automation/README.md
+++ b/crates/automation/README.md
@@ -21,6 +21,9 @@ them with the image's current orientation. Full turns retain its appearance, rec
 and flips. Angles that are not multiples of 90 are refused without changing the document or
 its undo/redo history.
 
+`page_add_text`, `content_update` and `text_edit` take per-line `aligns`. An `"inherit"` entry
+follows the box-level `align`; legacy `null` entries remain accepted with the same meaning.
+
 `Content` is `Json(Value)` or `Png { data, width, height }`. Errors are `UnknownTool`, `InvalidArgs` (the call didn't match the schema) or `Failed` (a readable message for the agent).
 
 ## Conventions
diff --git a/crates/automation/src/content.rs b/crates/automation/src/content.rs
index 7518072d1c..6b25c31f61 100644
--- a/crates/automation/src/content.rs
+++ b/crates/automation/src/content.rs
@@ -83,10 +83,10 @@ pub(crate) fn parse_align(al: &str) -> Result<TextAlign> {
 /// Most entries `aligns` takes: one per paragraph, and no text has this many.
 const MAX_ALIGNS: usize = 4096;
 
-/// `aligns`: each paragraph's (line's) own alignment, or null where it follows `align`.
+/// `aligns`: each paragraph's (line's) own alignment, or inherit/null where it follows `align`.
 pub(crate) fn opt_aligns(a: &Args) -> Result<Option<Vec<Option<TextAlign>>>> {
     let Some(v) = a.get("aligns") else { return Ok(None) };
-    let items = v.as_array().ok_or_else(|| bad("aligns must be an array of left, center, right, justify or null"))?;
+    let items = v.as_array().ok_or_else(|| bad("aligns must be an array of left, center, right, justify, inherit or null"))?;
     if items.len() > MAX_ALIGNS {
         return Err(bad(format!("aligns takes at most {MAX_ALIGNS} entries")));
     }
@@ -94,8 +94,9 @@ pub(crate) fn opt_aligns(a: &Args) -> Result<Option<Vec<Option<TextAlign>>>> {
         .iter()
         .map(|v| match v {
             Value::Null => Ok(None),
+            Value::String(s) if s == "inherit" => Ok(None),
             Value::String(s) => parse_align(s).map(Some),
-            _ => Err(bad("each entry of aligns is left, center, right, justify or null")),
+            _ => Err(bad("each entry of aligns is left, center, right, justify, inherit or null")),
         })
         .collect::<Result<Vec<_>>>()
         .map(Some)
diff --git a/crates/automation/src/tools.rs b/crates/automation/src/tools.rs
index 427bdc72f6..233bb101cd 100644
--- a/crates/automation/src/tools.rs
+++ b/crates/automation/src/tools.rs
@@ -637,7 +637,7 @@ pub fn tools() -> Vec<ToolDef> {
                 "font": { "type": "string", "enum": ["helvetica", "times", "courier"] }, "size": { "type": "number", "minimum": 1, "maximum": 500 },
                 "bold": { "type": "boolean" }, "italic": { "type": "boolean" }, "color": { "type": "string" },
                 "align": { "type": "string", "enum": ["left", "center", "right", "justify"] },
-                "aligns": { "type": "array", "maxItems": 4096, "items": { "enum": ["left", "center", "right", "justify", null] }, "description": "Each paragraph's (line's) own alignment, by index; null follows align." },
+                "aligns": { "type": "array", "maxItems": 4096, "items": { "type": "string", "enum": ["left", "center", "right", "justify", "inherit"] }, "description": "Each paragraph's (line's) own alignment, by index; inherit (or legacy null) follows align." },
                 "char_spacing": { "type": "number", "minimum": -500, "maximum": 500, "description": "Points after each character." },
             }),
             &["doc", "page", "text"],
@@ -660,7 +660,7 @@ pub fn tools() -> Vec<ToolDef> {
                     "font": { "type": "string", "enum": ["helvetica", "times", "courier"] }, "size": { "type": "number", "minimum": 1, "maximum": 500 },
                     "bold": { "type": "boolean" }, "italic": { "type": "boolean" }, "color": { "type": "string" },
                     "align": { "type": "string", "enum": ["left", "center", "right", "justify"] },
-                    "aligns": { "type": "array", "maxItems": 4096, "items": { "enum": ["left", "center", "right", "justify", null] }, "description": "Each paragraph's (line's) own alignment, by index; null follows align." },
+                    "aligns": { "type": "array", "maxItems": 4096, "items": { "type": "string", "enum": ["left", "center", "right", "justify", "inherit"] }, "description": "Each paragraph's (line's) own alignment, by index; inherit (or legacy null) follows align." },
                     "char_spacing": { "type": "number", "minimum": -500, "maximum": 500, "description": "Points after each character." },
                     "rotate": { "type": "integer" }, "flip_h": { "type": "boolean" }, "flip_v": { "type": "boolean" },
                     "crop": { "type": "array", "items": { "type": "number", "minimum": 0, "maximum": 0.95 }, "minItems": 4, "maxItems": 4, "description": "Fractions trimmed: left, bottom, right, top. Left and right together, and bottom and top together, trim at most 0.95." },
@@ -1429,7 +1429,7 @@ pub fn tools() -> Vec<ToolDef> {
                     "size": { "type": "number", "exclusiveMinimum": 0 },
                     "color": { "type": "string", "description": "#rrggbb" },
                     "align": { "type": "string", "enum": ["left", "center", "right", "justify"] },
-                    "aligns": { "type": "array", "maxItems": 4096, "items": { "enum": ["left", "center", "right", "justify", null] }, "description": "Each paragraph's (line's) own alignment, by index; null follows align." },
+                    "aligns": { "type": "array", "maxItems": 4096, "items": { "type": "string", "enum": ["left", "center", "right", "justify", "inherit"] }, "description": "Each paragraph's (line's) own alignment, by index; inherit (or legacy null) follows align." },
                     "underline": { "type": "boolean" },
                     "line_spacing": { "type": "number", "description": "Multiple of the font size (1.2 is ordinary)." },
                     "dx": { "type": "number", "description": "Paragraph only: move right by this many points (negative: left)." },
diff --git a/crates/automation/tests/it/automation.rs b/crates/automation/tests/it/automation.rs
index aa778273da..8cff9fc4aa 100644
--- a/crates/automation/tests/it/automation.rs
+++ b/crates/automation/tests/it/automation.rs
@@ -664,6 +664,44 @@ fn tool_table_is_well_formed() {
     }
 }
 
+fn assert_homogeneous_enums(schema: &Value, path: &str) {
+    fn json_kind(value: &Value) -> &'static str {
+        match value {
+            Value::Null => "null",
+            Value::Bool(_) => "boolean",
+            Value::Number(_) => "number",
+            Value::String(_) => "string",
+            Value::Array(_) => "array",
+            Value::Object(_) => "object",
+        }
+    }
+
+    if let Some(values) = schema.get("enum").and_then(Value::as_array) {
+        let first = values.first().map(json_kind);
+        assert!(values.iter().map(json_kind).all(|kind| Some(kind) == first), "mixed enum types at {path}: {values:?}");
+    }
+    match schema {
+        Value::Object(object) => {
+            for (key, child) in object {
+                assert_homogeneous_enums(child, &format!("{path}.{key}"));
+            }
+        }
+        Value::Array(array) => {
+            for (index, child) in array.iter().enumerate() {
+                assert_homogeneous_enums(child, &format!("{path}[{index}]"));
+            }
+        }
+        _ => {}
+    }
+}
+
+#[test]
+fn tool_schema_enums_have_one_json_type() {
+    for tool in tools() {
+        assert_homogeneous_enums(&tool.input_schema, tool.name);
+    }
+}
+
 #[test]
 fn explicit_font_and_disjoint_ranges_save_reopen_through_tools() {
     let dir = workdir("font-ranges");
@@ -9878,7 +9916,11 @@ fn added_text_lines_take_their_own_alignments() {
     let dir = workdir("paragraph-aligns");
     let mut a = auto(&dir);
     let id = ok(&mut a, "doc_create", json!({"from":"blank","width":600,"height":400}))["doc"].as_u64().unwrap();
-    ok(&mut a, "page_add_text", json!({"doc":id,"page":1,"text":"Left line\nRight line","at":[40,50],"width":500,"size":12,"aligns":[null,"right"]}));
+    ok(
+        &mut a,
+        "page_add_text",
+        json!({"doc":id,"page":1,"text":"Left line\nRight line\nInherited line","at":[40,50],"width":500,"size":12,"aligns":[null,"right","inherit"]}),
+    );
     let rect = |a: &mut Automation, text: &str| -> Vec<f64> {
         let lines = ok(a, "text_lines", json!({"doc":id,"page":1}));
         let line = lines["lines"].as_array().unwrap().iter().find(|l| l["text"] == text).cloned().unwrap();
@@ -9886,10 +9928,13 @@ fn added_text_lines_take_their_own_alignments() {
     };
     assert!((rect(&mut a, "Left line")[0] - 40.0).abs() < 1.0);
     assert!((rect(&mut a, "Right line")[2] - 540.0).abs() < 1.0, "{:?}", rect(&mut a, "Right line"));
+    assert!((rect(&mut a, "Inherited line")[0] - 40.0).abs() < 1.0);
     // The whole box centred: the right-aligned line goes with it.
     ok(&mut a, "content_update", json!({"doc":id,"page":1,"index":1,"align":"center"}));
     let right = rect(&mut a, "Right line");
     assert!(((right[0] + right[2]) / 2.0 - 290.0).abs() < 1.0, "{right:?}");
+    let inherited = rect(&mut a, "Inherited line");
+    assert!(((inherited[0] + inherited[2]) / 2.0 - 290.0).abs() < 1.0, "{inherited:?}");
     assert!(a.call("content_update", &json!({"doc":id,"page":1,"index":1,"aligns":["sideways"]})).is_err());
     assert!(a.call("content_update", &json!({"doc":id,"page":1,"index":1,"aligns":"right"})).is_err());
 }