fix(MCPServer): Session tool handler not used due to variable shadowing

[cryo-zd]

Problem
  This PR fixes a bug where session-specific tool handlers were never used, and MCPServer always fell back to global tool handlers.
  The issue was caused by variable shadowing in the following block of code:

if sessionWithTools, ok := session.(SessionWithTools); ok {
    ...
    if sessionOk {
        ok = true
    }
}

  The ok declared in if sessionWithTools, ok := .... shadows the outer ok variable declared in the function:

var ok bool

  As a result, setting ok = true inside this if block had no effect on the outer variable, and the following loginc:

if !ok {
    //fallback to global tools
}

was always executed, even if a session tool was actually found.

Fix
  This fix simply avoids shadowing by renaming the inner variable:

if sessionWithTools, typeAssertOk := session.(SessionWithTools); typeAssertOk {

  This ensures that the outer ok variable reflects whether a session-specific tool was found and used.

Summary by CodeRabbit

• Tests

  • Added a test to verify that session-specific tools correctly override global tools with the same name when called within a session context.

• Refactor

  • Improved variable naming in session tool handling to prevent naming conflicts and enhance code clarity.

[coderabbitai]

Walkthrough

This change updates the handleToolCall method in the MCP server to use a more specific variable name when performing a type assertion to the SessionWithTools interface, preventing variable shadowing. Additionally, a new test is introduced to verify that a session-specific tool correctly overrides a global tool with the same name, ensuring that the session's tool handler is invoked when expected.

Changes

File(s)	Change Summary
server/server.go	Renamed the variable used in the type assertion for SessionWithTools from ok to typeAssertOk in handleToolCall to avoid shadowing the outer ok variable. No logic changes.
server/session_test.go	Added TestMCPServer_CallSessionTool to test that a session-specific tool overrides a global tool of the same name, confirming correct handler invocation.

Possibly related PRs

• feat(sse): Add SessionWithTools support to SSEServer #232: Adds SessionWithTools support to the sseSession struct, introducing methods for managing session tools, which is closely related to this PR's focus on session-specific tool handling and the SessionWithTools interface.

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📜 Recent review details

Configuration used: CodeRabbit UI
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📥 Commits

Reviewing files that changed from the base of the PR and between 5244489 and 12ec7be.

📒 Files selected for processing (2)

• server/server.go (1 hunks)
• server/session_test.go (2 hunks)

🧰 Additional context used

🧬 Code Graph Analysis (1)

server/server.go (1)

server/session.go (1)

• SessionWithTools (23-31)

🔇 Additional comments (2)

server/server.go (1)

859-859: Good fix to prevent variable shadowing.

Renaming the variable from ok to typeAssertOk in the type assertion solves the variable shadowing issue that was causing session-specific tool handlers to be ignored. This change ensures that setting ok = true at line 864 properly affects the outer variable used for determining whether to fall back to global tools.

server/session_test.go (1)

299-355: Well-designed test case for the fixed issue.

This test correctly verifies that a session-specific tool can override a global tool with the same name, which directly tests the functionality fixed in server/server.go. The test creates both a global and session-specific tool with the same name but different responses, then verifies that the session-specific tool is correctly invoked.

✨ Finishing Touches

• 📝 Generate Docstrings

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[rwjblue-glean]

Nice catch!