Amazon Q CLI error: ValidationException - Improperly formed request

### Checks

- [x] I have searched [github.com/aws/amazon-q-developer-cli/issues](https://github.com/aws/amazon-q-developer-cli/issues?q=) and there are no duplicates of my issue
- [x] I have run `q doctor` in the affected terminal session
- [x] I have run `q restart` and replicated the issue again

### Operating system

macOS 15.3.2 (24D81)

### Expected behaviour

Amazon Q CLI should process the request and provide a response without validation errors.

### Actual behaviour

Amazon Q is having trouble responding with error:
0: unhandled error (ValidationException)
1: service error
2: unhandled error (ValidationException)
3: Error { code: "ValidationException", message: "Improperly formed request.", aws_request_id: "a7eb39db-7f56-459a-a140-bed1f0fa0b02" }

Location:
crates/q_cli/src/cli/chat/mod.rs:668

```
[chat-transcript]
> /tools

> explain this package

I'll need to examine the my package to provide you with a detailed explanation. Let me check the available files and structure first.
[Tool uses: fs_read]

Let me check the source code structure to better understand the package:
[Tool uses: fs_read]

[Tool uses: fs_read]

Amazon Q is having trouble responding right now:
0: unhandled error (ValidationException)
1: service error
2: unhandled error (ValidationException)
3: Error { code: "ValidationException", message: "Improperly formed request.", aws_request_id: "a7eb39db-7f56-459a-a140-bed1f0fa0b02" }

Location:
crates/q_cli/src/cli/chat/mod.rs:668

Backtrace omitted. Run with RUST_BACKTRACE=1 environment variable to display it.
Run with RUST_BACKTRACE=full to include source snippets.

> report_issue

I'll help you report an issue. To proceed with creating a GitHub issue, I need a title for the issue and optionally some details about what happened. Could you please provide:

1. A title for the GitHub issue
2. Optionally, describe the actual behavior you experienced
3. Optionally, describe the expected behavior
4. Optionally, provide steps to reproduce the issue

Once you provide this information, I can help you submit the issue report.
[Tool uses: none]

> Amazon Q is having trouble responding right now:>
0: unhandled error (ValidationException)>
1: service error>
2: unhandled error (ValidationException)>
3: Error { code: "ValidationException", message: "Improperly formed request.", aws_request_id: "a7eb39db-7f56-459a-a140-bed1f0fa0b02" }>
>
Location:>
crates/q_cli/src/cli/chat/mod.rs:668>
>
Backtrace omitted. Run with RUST_BACKTRACE=1 environment variable to display it.>
Run with RUST_BACKTRACE=full to include source snippets.

I'll help you report this issue. Let me prepare the GitHub issue report for you.
[Tool uses: report_issue]
```

### Steps to reproduce

Using q chat CLI command and attempting to explore a codebase with fs_read function calls.

### Environment

```yaml

[q-details]
version = "1.7.3"
hash = "3e4ae79d371315e80ddac772b43fff2cba314104"
date = "2025-04-10T05:48:16.435186Z (12d ago)"
variant = "full"

[system-info]
os = "macOS 15.3.2 (24D81)"
chip = "Apple M1 Pro"
total-cores = 10
memory = "32.00 GB"

[environment]
cwd = "/Users/USER/workspace/Launcher/src/Launcher"
cli-path = "/Users/USER/workspace/Launcher/src/Launcher"
os = "Mac"
shell-path = "/Users/USER/.toolbox/tools/toolbox/1.1.1762.0/toolbox-exec"
shell-version = "5.9"
terminal = "iTerm 2"
install-method = "toolbox"

[env-vars]
PATH = "/Users/USER/.codeium/windsurf/bin:~/Library/Android/sdk/platform-tools:/Users/USER/.bin:/opt/homebrew/opt/node@16/bin:/Users/USER/.pyenv/shims:/Users/USER/.pyenv/bin:/opt/homebrew/opt/node@18/bin:/Users/USER/perl5/bin:/opt/homebrew/opt/node@14/bin:/opt/homebrew/opt/gnu-sed/libexec/gnubin:/Users/USER/.toolbox/bin:/Users/USER/.codeium/windsurf/bin:~/Library/Android/sdk/platform-tools:/Users/USER/.bin:/opt/homebrew/opt/node@16/bin:/Users/USER/.pyenv/bin:/Users/USER/.nvm/versions/node/v18.19.1/bin:/opt/homebrew/opt/node@18/bin:/Users/USER/miniconda3/bin:/Users/USER/miniconda3/condabin:/Users/USER/perl5/bin:/opt/homebrew/opt/node@14/bin:/opt/homebrew/opt/gnu-sed/libexec/gnubin:/Users/USER/.toolbox/bin:/Library/Frameworks/Python.framework/Versions/3.11/bin:/opt/homebrew/bin:/opt/homebrew/sbin:/usr/local/bin:/System/Cryptexes/App/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/local/bin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/bin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/appleinternal/bin:/Applications/iTerm.app/Contents/Resources/utilities:/Users/USER/.local/bin:/Users/USER/Library/Application Support/JetBrains/Toolbox/scripts:/Users/USER/.local/binexport:/Users/USER/workspace/SpyDevTools/src/SpyDevTools/bin:/Users/USER/Library/Android/sdk/platform-tools:/Users/USER/.local/binexport:/Users/USER/workspace/SpyDevTools/src/SpyDevTools/bin:/Users/USER/Library/Android/sdk/platform-tools:/Users/USER/.local/bin"
QTERM_SESSION_ID = "a8cca77ed1914d4fa17c6568c2b39116"
Q_SET_PARENT_CHECK = "1"
Q_TERM = "1.7.3"
SHELL = "/bin/zsh"
TERM = "xterm-256color"
__CFBundleIdentifier = "com.googlecode.iterm2"

[chat-settings]
interactive=true

[chat-trusted_tools]

[chat-failed_request_ids]
none

[chat-context]
current_profile=default
profiles=
default

global_context=
.amazonq/rules/**/*.md
README.md
AmazonQ.md

profile_context=none

files=
/Users/user/workspace/Launcher/src/Launcher/README.md, 273 B
total context size=273 B
```