git tools crash stdio transport on extra_param and very_long_string input

[SMWundefined]

When an MCP client sends edge-case inputs to git tools (git_status, git_log, git_diff),
two input patterns crash the stdio transport entirely instead of returning an error response:

1. An extra undeclared parameter (e.g. {"repo_path": "...", "unexpected_field": "value"})
2. A very long string value (10,000+ characters)

Both cause the connection to drop. The client receives no error response — the transport dies.

These inputs are realistic: LLM agents routinely hallucinate extra parameters or generate
overly long argument values. This is normal traffic, not adversarial input.

Reproduction:

pip install ratemyagent
ratemyagent scan --target mcp \
  --uri "stdio://uvx mcp-server-git --repository /path/to/any/repo" \
  --tool git_log --tool-args '{"repo_path": "/path/to/any/repo"}' \
  --probes contract --requests 5

Result: Contract probe reports 6/18 edge cases crashed the transport.
Expected: Invalid input should return a JSON-RPC error response, not crash the connection.

Tested against mcp-server-git 2026.8.18, mcp SDK 1.x, Python 3.12, macOS arm64.

[SMWundefined]

Same behavior observed on server-filesystem (read_file, write_file, list_directory)