Hosted search_issues silently returns incorrect keyword results

Bug description

The hosted GitHub MCP search_issues tool silently returns materially incorrect keyword search results while reporting incomplete_results: false.

This reproduces when calling the hosted endpoint directly, without an MCP aggregator.

Environment

• Endpoint: https://api.githubcopilot.com/mcp
• Server: github-mcp-server
• Reported version: github-mcp-server/remote-34ac9c16f8fd3e2a5af74929de89de3a11e98f9b
• Protocol negotiated: 2025-11-25
• Date verified: 2026-08-31

Reproduction

Call search_issues with ordinary GitHub issue search syntax already scoped to issues.

Query	Hosted MCP total_count	GitHub REST GET /search/issues
repo:modelcontextprotocol/python-sdk transport	0	410
repo:modelcontextprotocol/python-sdk windows	0	95
repo:anthropics/claude-code hooks	3	8016
memory leak	40	407744 at verification time

The three returned hooks results were titled plugins, trap, and Hook before Exit, which also does not match normal GitHub full-text search behavior.

Passing owner and repo separately with a keyword-only query produced the same incorrect results, so this is not limited to embedding repo: in query.

Qualifier-only searches such as repo:modelcontextprotocol/python-sdk label:bug return plausible counts, which makes the keyword failure easy for an agent to trust silently.

Expected behavior

search_issues should preserve GitHub issue search semantics and return counts/results consistent with the GitHub REST Search API for the same effective query, or return an explicit error/unsupported-query signal.

Actual behavior

The tool returns a successful response with incomplete_results: false, but keyword matches are missing or unrelated.

Impact

Agents can incorrectly conclude that an issue, bug report, or prior discussion does not exist. This is a correctness failure rather than only a ranking-quality difference.