diff --git a/README.md b/README.md
index e653ffc..c5b1157 100644
--- a/README.md
+++ b/README.md
@@ -211,7 +211,7 @@ output back to the terminal stay testable.
 
 ## Command line and CI
 
-`cargo install termlens-cli` gives the same harness as a command:
+`cargo install termlens-cli --locked` gives the same harness as a command:
 
 ```sh
 termlens inspect --size 120x40 myapp     # run a program, print its screen
diff --git a/skills/termlens/SKILL.md b/skills/termlens/SKILL.md
index 20804ec..d5ac39d 100644
--- a/skills/termlens/SKILL.md
+++ b/skills/termlens/SKILL.md
@@ -539,7 +539,7 @@ directory (see §9b).
 
 ## 9b. At a shell prompt, and in CI
 
-- `cargo install termlens-cli` gives the harness as a command: `termlens
+- `cargo install termlens-cli --locked` gives the harness as a command: `termlens
   inspect --size 120x40 myapp` prints what a program shows (`--ansi` for
   colour), `termlens diff old.snap new.snap.new` prints the cell diff of two
   saved screens and exits 1 if anything changed, `termlens render --svg