Improve LLM tool parameter guidance and add E2E testing framework

[janisz]

Description

Enhanced tool descriptions and parameter schemas to better guide LLMs on when to use optional parameters and which tools to select for different query types. Added mcp-testing-framework configuration with 8 test cases covering CVE queries and cluster operations, achieving 87.5% pass rate with GPT-5 models.

Validation

./scripts/run-tests.sh
══════════════════════════════════════════════════════════
  StackRox MCP E2E Testing with Gevals
══════════════════════════════════════════════════════════

Loading environment variables from .env...
Configuration:
  Agent Model: gpt-4o
  Judge Model: gpt-4o
  MCP Server: stackrox-mcp (via go run)

Running gevals tests...


=== Starting Evaluation ===

Task: list-clusters
  Difficulty: easy
  → Running agent...
  → Verifying results...
  ✓ Task passed

Task: cve-affecting-workloads
  Difficulty: easy
  → Running agent...
  → Verifying results...
  ✓ Task passed

Task: cve-affecting-clusters
  Difficulty: easy
  → Running agent...
  → Verifying results...
  ✓ Task passed

Task: cve-nonexistent
  Difficulty: easy
  → Running agent...
  → Verifying results...
  ✓ Task passed

Task: cve-cluster-scooby
  Difficulty: easy
  → Running agent...
  → Verifying results...
  ✓ Task passed

Task: cve-cluster-maria
  Difficulty: easy
  → Running agent...
  → Verifying results...
  ✓ Task passed

Task: cve-clusters-general
  Difficulty: easy
  → Running agent...
  → Verifying results...
  ✓ Task passed

Task: cve-cluster-list
  Difficulty: easy
  → Running agent...
  → Verifying results...
  ✓ Task passed

=== Evaluation Complete ===

📄 Results saved to: gevals-stackrox-mcp-e2e-out.json

=== Results Summary ===

Task: list-clusters
  Path: /home/janisz/go/src/github.com/stackrox/stackrox-mcp/e2e-tests/gevals/tasks/list-clusters.yaml
  Difficulty: easy
  Task Status: PASSED
  Assertions: PASSED (3/3)

Task: cve-affecting-workloads
  Path: /home/janisz/go/src/github.com/stackrox/stackrox-mcp/e2e-tests/gevals/tasks/cve-affecting-workloads.yaml
  Difficulty: easy
  Task Status: PASSED
  Assertions: PASSED (3/3)

Task: cve-affecting-clusters
  Path: /home/janisz/go/src/github.com/stackrox/stackrox-mcp/e2e-tests/gevals/tasks/cve-affecting-clusters.yaml
  Difficulty: easy
  Task Status: PASSED
  Assertions: PASSED (3/3)

Task: cve-nonexistent
  Path: /home/janisz/go/src/github.com/stackrox/stackrox-mcp/e2e-tests/gevals/tasks/cve-nonexistent.yaml
  Difficulty: easy
  Task Status: PASSED
  Assertions: PASSED (3/3)

Task: cve-cluster-scooby
  Path: /home/janisz/go/src/github.com/stackrox/stackrox-mcp/e2e-tests/gevals/tasks/cve-cluster-scooby.yaml
  Difficulty: easy
  Task Status: PASSED
  Assertions: PASSED (3/3)

Task: cve-cluster-maria
  Path: /home/janisz/go/src/github.com/stackrox/stackrox-mcp/e2e-tests/gevals/tasks/cve-cluster-maria.yaml
  Difficulty: easy
  Task Status: PASSED
  Assertions: PASSED (3/3)

Task: cve-clusters-general
  Path: /home/janisz/go/src/github.com/stackrox/stackrox-mcp/e2e-tests/gevals/tasks/cve-clusters-general.yaml
  Difficulty: easy
  Task Status: PASSED
  Assertions: PASSED (3/3)

Task: cve-cluster-list
  Path: /home/janisz/go/src/github.com/stackrox/stackrox-mcp/e2e-tests/gevals/tasks/cve-cluster-list.yaml
  Difficulty: easy
  Task Status: PASSED
  Assertions: PASSED (3/3)

=== Overall Statistics ===
Total Tasks: 8
Tasks Passed: 8/8
Assertions Passed: 24/24

=== Statistics by Difficulty ===

easy:
  Tasks: 8/8
  Assertions: 24/24

══════════════════════════════════════════════════════════
  Tests Completed Successfully!
══════════════════════════════════════════════════════════

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 77.58%. Comparing base (53e4b0b) to head (2868f53).
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #26      +/-   ##
==========================================
+ Coverage   77.36%   77.58%   +0.22%     
==========================================
  Files          26       26              
  Lines        1109     1120      +11     
==========================================
+ Hits          858      869      +11     
  Misses        216      216              
  Partials       35       35              

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