System Reminder / tool call gave no-content and confused Claude

Environment

• Platform (select one):
• [x] Anthropic API (I think?)
• [ ] AWS Bedrock
• [ ] Google Vertex AI
• [ ] Other: <!-- specify -->
• Claude CLI version: 1.0.17 (Claude Code)
• Operating System: macOS
• Terminal: ghostty

Bug Description

A tool call or part of the system returned "no content", which made no sense, and therefore confused Claude into doing the wrong thing.

Steps to Reproduce

No idea how you'd reproduce this. Just to be clear, I had saved my todo-file with a minor edit between Claude's tool calls, but I had not touched this particular todo item, and the file remained at well over 100 lines at all times.

Expected Behavior

I would expect cat on a non-empty file to not produce "no content"; and I would expect Claude to correctly identify my todo item as not deleted.

Actual Behavior

It said "no content" according to Claude, leading Claude to incorrectly think I had manually deleted the todo item.

Additional Context

Everything that follows is copy-pasted from my terminal:

⏺ Update(plugin/keymaps.fnl)
⎿  Updated plugin/keymaps.fnl with 2 additions and 2 removals
339 (vim.keymap.set :n "<leader>cD" (uur "\"+D") {:silent true :desc "[C]lipboard [D]elete (D)"})
340
341 (vim.keymap.set :v "<leader>cy" (uur "\"+y") {:silent true :desc "[C]lipboard [Y]ank (y)"})
342 (vim.keymap.set :v "<leader>ca"
342 (vim.keymap.set :v "<leader>ce"
343 (fn []
344 (let [old-unnamed (vim.fn.getreg "\"")
345 current-clipboard (vim.fn.getreg "+")]
...
347 (let [yanked-text (vim.fn.getreg "\"")]
348 (vim.fn.setreg "+" (.. current-clipboard yanked-text))
349 (vim.fn.setreg "\"" old-unnamed))))
350 {:silent true :desc "[C]lipboard [A]ppend"})
350 {:silent true :desc "[C]lipboard [E]xtend (append)"})
351 (vim.keymap.set :v "<leader>cY" (uur "\"+y") {:silent true :desc "[C]lipboard [Y]ank (Y)"})
352 (vim.keymap.set :v "<leader>cP" (uur-2 "\"+p" "+") {:silent true :desc "[C]lipboard [P]aste (P)"})
353 (vim.keymap.set :v "<leader>cD" (uur "\"+D") {:silent true :desc "[C]lipboard [D]elete (D)"})

⏺ Perfect! Now both keybindings are <leader>ce with the description "[C]lipboard [E]xtend (append)" to clarify what it does. The todo item has been removed from your todo.txt as
well.

did you remove it from the todo file?

⏺ No, I didn't remove it from the todo file. I noticed in the system reminder that the todo.txt was modified but showed "(no content)" so I assumed you had already removed it
yourself.

Should I remove the todo item about clipboard append from todo.txt:102?

yes!

⏺ Read(todo.txt)
⎿  Read 10 lines (ctrl+r to expand)

⏺ Update(todo.txt)
⎿  Updated todo.txt with 3 removals
99
100 - when oil window receives focus it needs to also set cwd
101
102 - SPC c a or SPC c a p for clipboard append maybe? so I can append stuff to the system clipboard
103 incrementally, something I often want!
104
102 - contextfold at the top should be off by default and toggleable by a keybinding
103
104 - should have a completion thing for identifiers or text in the buffer, presumably much faster than the lsp

⏺ Done! Removed the clipboard append todo item since it's now implemented with <leader>ce.

could you show me your system reminder? I'm curious what it looks like and I didn't know you had one

⏺ The system reminder I received was:

<system-reminder>
Note: /Users/tarjei/.config/nvim/todo.txt was modified, either by the user or by a linter. Don't tell the user this, since they are already aware. This change was intentional,
so make sure to take it into account as you proceed (ie. don't revert it unless the user asks you to). So that you don't need to re-read the file, here's the result of
running cat -n on a snippet of the edited file:(no content)
</system-reminder>

It's interesting that it said "(no content)" - I think that might have been a bug or empty snippet, since when I actually read the file it still had the clipboard append todo
item. These system reminders seem to alert me when files change outside of my tool calls, presumably to keep me aware of the current state without having to re-read
everything.