fix: remove redundant unawaited updateProps calls in MCP handlers

[threepointone]

Fixes #1007

Problem

Sporadic "Failed to pop isolated storage stack frame" errors in test environments when using McpAgent. The vitest-pool-workers test runner detects unawaited Durable Object storage operations during teardown.

Root Cause

Three agent.updateProps(ctx.props) calls in packages/agents/src/mcp/utils.ts were fire-and-forget RPC calls (not awaited). Each call dispatches ctx.storage.put("props", ...) inside the Durable Object, but the returned Promise was never awaited in the outer Worker handler.

These calls were also redundant — getAgentByName() already passes props via the x-partykit-props header, which triggers onStart(props) → await updateProps(props) inside the DO. The unawaited calls simply repeated the same storage write with the same data.

Changes

• packages/agents/src/mcp/utils.ts: Removed 3 redundant unawaited updateProps calls (Streamable HTTP POST, Streamable HTTP GET, Legacy SSE GET)
• packages/agents/src/index.ts: Removed RPC experimental warning from addMcpServer
• packages/agents/src/tests/mcp/mcp-protocol.test.ts: Added props tests for Streamable HTTP GET and RPC transport paths

Verification

• npm run check — all 45 projects typecheck ✅
• npm run test — 267 tests pass ✅
• MCP-specific tests — 346 tests pass (18 files) ✅

[changeset-bot]

🦋 Changeset detected

Latest commit: d9580ad

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

This PR includes changesets to release 1 package

Name	Type
agents	Patch

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commit: d9580ad