Read tool gets called when knowledge tool encounters errors with process knowledge files resulting in string length exceeded errors.

[sangee2004]

Electron build -bf86f18e1c

Steps to reproduce the problem:

1. Chart with Tildy
2. Add a pdf file (6.5 MB in my case) using "Add Knowledge"
3. Tried to ask question about information in this pdf file which resulted in knowledge tool not being able to answer and LLM resorted to reading the file using read tool.

This results in following string length exceeded errors:

Expected Behavior:
Prevent Read tool from being called for large files which it is not able to handle and results in failure.

[cjellick]

need to think about the best way to handle this. the read tool itself should be more ...reluctant?... to blow out the context.

[cjellick]

This exact situation shouldn't happen any longer as knowledge has been decoupled from the workspace - #360

But @g-linville I still want you to make it so that the read tool doesnt try to read binary files (and potentially just large files or it cuts them off).

[g-linville]

This should be good now. The description for sys.read tells the LLM not to use it to read binary files, and sys.read will now return an error back to the LLM if it detects that a file is not plain text.

[sangee2004]

Tested with latest build from electron - 81ca1d72a2

sys.read tool is not being used for reading a pdf file .