fix: normalize MCP elicitation requests with empty message

[omeraplak]

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• The commit message follows our guidelines: https://voltagent.dev/docs/community/contributing/#commit-convention

Bugs / Features

• Related issue(s) linked
• Tests for the changes have been added
• Docs have been added / updated
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What is the current behavior?

What is the new behavior?

fixes (issue)

Notes for reviewers

---

Summary by cubic

Fixes empty-message MCP elicitations by deriving a prompt from the JSON Schema so handlers always receive a usable message. Prevents blank prompts when servers omit message.

• Bug Fixes

  • If message is empty, fill it from requestedSchema.description; if missing, fall back to the first property’s description or title.
  • Added a unit test to ensure the derived message is passed to the elicitation handler.

• New Features

  • Added a Go HTTP MCP server in the example that intentionally elicits with an empty message to verify the fallback.
  • Updated the example to connect to an external MCP server; README includes setup and run instructions.

^{Written for commit eee121b. Summary will update automatically on new commits.}

[changeset-bot]

🦋 Changeset detected

Latest commit: eee121b

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@voltagent/core	Patch

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[cubic-dev-ai]

1 issue found across 8 files

Prompt for AI agents (all issues)

Check if these issues are valid — if so, understand the root cause of each and fix them.


<file name="examples/with-mcp-elicitation/src/index.ts">

<violation number="1" location="examples/with-mcp-elicitation/src/index.ts:13">
P2: Dead code: `startMcpServer(port, logger)` will never be called because `serverUrl` is hardcoded to a truthy string. The `||` fallback is unreachable. Either remove the fallback or use a conditional that can actually be falsy (e.g., uncomment the env var access).</violation>
</file>

_{Reply to cubic to teach it or ask questions. Tag @cubic-dev-ai to re-run a review.}

[cubic-dev-ai]

P2: Dead code: startMcpServer(port, logger) will never be called because serverUrl is hardcoded to a truthy string. The || fallback is unreachable. Either remove the fallback or use a conditional that can actually be falsy (e.g., uncomment the env var access).

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At examples/with-mcp-elicitation/src/index.ts, line 13:

<comment>Dead code: `startMcpServer(port, logger)` will never be called because `serverUrl` is hardcoded to a truthy string. The `||` fallback is unreachable. Either remove the fallback or use a conditional that can actually be falsy (e.g., uncomment the env var access).</comment>

<file context>
@@ -9,14 +9,14 @@ const logger = createPinoLogger({
-
-const { url } = await startMcpServer(port, logger);
+const serverUrl = &quot;http://127.0.0.1:3142/mcp&quot;; // process.env.MCP_SERVER_URL?.trim();
+const resolvedUrl = serverUrl || (await startMcpServer(port, logger)).url;
 
 const mcpConfig = new MCPConfiguration({
</file context>

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