MCP: 'MCPRuntime built — N tools' boot log undercounts (stdio only) — misleading triage signal #22

New Issue

2026-05-12T19:05:02Z

KofTwentyTwo commented

2026-05-12 19:05:02 +00:00

(Migrated from github.com)

Summary

MCPRuntime built — N tools boot log undercounts: registeredToolNames() only returns stdio helper tools (3), not the 7 in-process tools registered into inProcessToolRegistry. The boot log perpetually shows MCPRuntime built — 3 tools while MCPBootHealthProbe correctly reports 10. A contributor reading the system log will conclude in-process tools didn't register and chase the wrong root cause.

Evidence

File: App/AppDelegate.swift:618-619:

let toolCount = await runtime.client.registeredToolNames().count
self.systemLogger?.info("MCPRuntime built — \(toolCount) tools")

runtime.client.registeredToolNames() returns stdio-only (3): get_time, get_clipboard, run_applescript
MCPBootHealthProbe at App/Boot/BootHealthProbes.swift:336-391 correctly counts both registries

Root cause / hypothesis

Today's commit 740bed4 addressed a related undercount in the probe; this log line was missed. The log line uses the runtime client's registered-names API which only knows about stdio servers.

Recommended fix

Include inProcessToolRegistry.registered().count in the log line, or just delete the line and rely on MCPBootHealthProbe for the count.

let stdioCount = await runtime.client.registeredToolNames().count
let inProcessCount = await self.inProcessToolRegistry.toolSchemas().count
self.systemLogger?.info("MCPRuntime built — \(stdioCount + inProcessCount) tools (\(stdioCount) stdio + \(inProcessCount) in-process)")

Test

After registering 7 in-process tools, assert boot log line includes the in-process count

Source

Audit: .planning/audit-2026-05-12/mcp-agent-audit.md (2026-05-12) — finding CRIT-3

## Summary `MCPRuntime built — N tools` boot log undercounts: `registeredToolNames()` only returns stdio helper tools (3), not the 7 in-process tools registered into `inProcessToolRegistry`. The boot log perpetually shows `MCPRuntime built — 3 tools` while `MCPBootHealthProbe` correctly reports 10. A contributor reading the system log will conclude in-process tools didn't register and chase the wrong root cause. ## Evidence - File: `App/AppDelegate.swift:618-619`: ```swift let toolCount = await runtime.client.registeredToolNames().count self.systemLogger?.info("MCPRuntime built — \(toolCount) tools") ``` - `runtime.client.registeredToolNames()` returns stdio-only (3): `get_time`, `get_clipboard`, `run_applescript` - `MCPBootHealthProbe` at `App/Boot/BootHealthProbes.swift:336-391` correctly counts both registries ## Root cause / hypothesis Today's commit `740bed4` addressed a related undercount in the probe; this log line was missed. The log line uses the runtime client's registered-names API which only knows about stdio servers. ## Recommended fix Include `inProcessToolRegistry.registered().count` in the log line, or just delete the line and rely on `MCPBootHealthProbe` for the count. ```swift let stdioCount = await runtime.client.registeredToolNames().count let inProcessCount = await self.inProcessToolRegistry.toolSchemas().count self.systemLogger?.info("MCPRuntime built — \(stdioCount + inProcessCount) tools (\(stdioCount) stdio + \(inProcessCount) in-process)") ``` ## Test - After registering 7 in-process tools, assert boot log line includes the in-process count ## Source - Audit: `.planning/audit-2026-05-12/mcp-agent-audit.md` (2026-05-12) — finding CRIT-3

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Reference: KofTwentyTwo/Jarvis#22