findings

🔎 Findings

Spotted while reading code. Not verified by tests. Fixed in code ⇒ 🗑️ remove row.

#	Kind	Finding	Proof
1	🪶	McpDispatcher javadoc says it "binds the v2025_11_25 models/codecs… move behind McpDialect when second version wired" — second version already wired via mappers. Stale.	McpDispatcher
2	⚠️	ServerEngine.responseMapper() / DefaultTachyonServer.responseMapper() always returns the 2025-11-25 mapper (imports v2025_11_25.McpProtocol.VERSION); used as fallback for task/progress notifications when session has no protocol.	DefaultTachyonServer#RESPONSE_MAPPERS, DefaultTachyonServer#notifyTaskStatus
3	⚠️	broadcastLog encodes with Protocols.list().getFirst() mapper for all sessions — relies on ServiceLoader file order (2025 first).	DefaultTachyonServer#broadcastLog
4	⚠️	McpDispatcher.dispatchContext(null) / DefaultDispatchContext.stateless also use Protocols.list().getFirst().	McpDispatcher#dispatchContext, DefaultDispatchContext#stateless
5	🪶	Channel logger name still legacy me.kpavlov.tachyon.transport.netty.channel.	McpChannelInitializer#CHANNEL_LOGGER_NAME
6	🪶	DefaultTaskRegistry.onChange replaces single listener; other registries append via ChangeSupport.	DefaultTaskRegistry#onChange
7	🪶	Session javadoc typo "unique string ID1".	Session
8	⚠️	ObservationListener marked @InternalApi + @Experimental, yet public extension point used by tachyon-opentelemetry and documented in ObservabilityConfig.Builder.listener. Contract unclear.	ObservationListener, Builder#slowRequestThreshold
9	🪶	In-memory stores defaulted twice: SessionConfig.Builder.build() and DefaultServerBuilder.build().	Builder#build, DefaultServerBuilder#build
10	⚠️	Notifications route onto POST-SSE only from the dispatching thread (ThreadLocal). Handler continuing on another thread ⇒ event goes to GET stream / dropped when none (stateful) — surprising for async tools.	OutboundSseStreamMessageRouter#logger, McpDispatcher#invokeHandlerAsync
11	⚠️	DefaultResourceRegistry.unregister(name) / find(name) pick arbitrary match when names collide (documented).	DefaultResourceRegistry
12	🪶	ResourceTemplateEntry is public record while sibling entries are package-private.	ResourceTemplateEntry
13	⚠️	UnsupportedProtocolVersionHandler errors use latest protocol mapper + HTTP 400 even for legacy-looking clients. Intentional per SEP-2575?	UnsupportedProtocolVersionHandler#channelRead
14	🪶	HandlerFutures is @InternalApi but lives in public tachyon-api and is referenced by user-facing AbstractToolHandler.	HandlerFutures
16	⚠️	Enum auto-completion registers through last-write-wins DefaultCompletionRegistry maps: explicit @McpCompletion from another service registered before the enum prompt/template is silently replaced. Same-service explicit completion is honored.	TachyonAnnotationProvider#registerEnumCompletion, DefaultCompletionRegistry#registerForPromptAsync
17	🐛	HTTP-status mismatch formats three placeholders with two arguments, throwing MissingFormatArgumentException.	JsonRpcResponseAssert.JsonRpcErrorAssert#hasHttpStatusCode
18	🐛	Method-not-found assertion requires HTTP 404 when a response is present; incompatible with legacy protocol HTTP 200 errors.	JsonRpcResponseAssert.JsonRpcErrorAssert#isMethodNotFound

❓ Open questions

• Multi-node: event log store (SessionEventStore) replay across nodes? Only SessionStore has CAS/generation fencing; in-memory event log is per process.
• 2026-07-28 + session.enabled(true): dispatcher bypasses sessions via supportsSessions=false; GET stream not matched for 2026 → only subscriptions/listen. Confirm intended.
• ⚠️ MISSING_REQUIRED_CLIENT_CAPABILITY maps to -32003 on 2025-11-25 (McpResponseMapper.java), -32021 only on 2026-07-28. SEP-2133 / Python SDK use -32021. Decide whether 2025 wire should switch.

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_{📄 source .llm-wiki/findings.md · updated 2026-09-17 · verified at 1a4081f4 · tags [meta, findings]}