epam/timebase-agent-plugins/timebase-cpp-client

TimeBase C++ Client

Mission

Teach correct use of the TimeBase native C++ client: connection lifecycle, positional field access via DataReader/DataWriter, cursors and loaders. Prefer MCP-grounded stream and schema facts before generating code.

Scope: Enterprise Edition only

This skill covers the Enterprise Edition (EE) dxapi client. Community Edition C++ is not yet supported by this skill. If a user asks specifically for a Community Edition C++ client, say so rather than improvising.

When to use this skill

Use only when the user explicitly requests C++ together with TimeBase.

Typical tasks:

• connecting via TickDb::createFromUrl and resolving streams,
• reads/writes via TickCursor/TickLoader with positional DataReader/DataWriter field access,
• historical, live/resettable (createCursor/reset), or reverse cursor reads,
• hand-written typed message codecs for polymorphic/type-name-dispatched read and write,
• stream creation via TickDb::createStream, TickDb::createFileStream, or QQL DDL,
• topic publish/poll via TopicDB/TickDirectLoader/TickMessagePoller,
• stream spaces, listing/clearing/renaming/destructively-deleting streams, locking, periodicity, write buffering,
• dynamic resubscription on a live cursor, multiplexed cursors,
• schema introspection or generic (schema-driven) decode from C++,
• in-place schema changes via TickStream::changeSchema,
• bound/parameterized QQL execution or QQL validation via compileQuery,
• acquiring and linking the dxapi native library (Nexus tar.gz on Linux/macOS, NuGet package on Windows),
• Decimal64/DFP field conversions,
• debugging connection, linking, or build failures.

Do not use for pure QQL authoring with no C++ code to write (use the qql-generator skill instead) or for pure MCP discovery with no code to write.

How to route requests

1. Confirm the user asked for C++ + TimeBase, not generic C++ help.
2. When stream names, schema, symbols, or time bounds matter, use MCP discovery first (references/mcp-assisted-discovery.md).
3. Detect how dxapi is already acquired in the target project (extracted archive on Linux/macOS, NuGet package or manually-vendored folder on Windows) and preserve it, don't move or re-derive it.
4. Before generating connection, stream, or cursor/loader code, verify the exact signature from the project's vendored dxapi headers (references/project-setup.md) rather than from memory.
5. Pick the smallest proven reference and example for the access pattern.
6. For library acquisition and build integration, use references/project-setup.md.

Mandatory policy

• Ground stream keys and schema from MCP or user input. Do not invent field names, type names, or stream keys.
• dxapi has no generated/bound message classes for arbitrary schemas. DataReader/DataWriter field access is positional, in the exact order fields are declared in the schema, there is no name-based field lookup. Get the field order right from get_stream_schema before writing any read/write code.
• When QQL authoring is central, use the QQL generator skill first. Return here for C++ execution via TickDb::executeQuery.
• Never invent an exact Nexus/NuGet artifact version. Use whatever is already pinned in the project, or ask the user to confirm the current release. See references/project-setup.md.
• Use placeholder-based credentials (e.g. NEXUS_USER/NEXUS_PASS) for Nexus/NuGet feed access, and preserve any existing naming convention the project already uses. Never hardcode credentials.
• Keep TickDb, TickCursor, and TickLoader lifecycle explicit: wrap in std::unique_ptr and call close() on every exit path, including exceptions.
• Start read-only unless writes are required. Do not write to streams unless the user asked.
• Treat TickStream::clear()/truncate()/purge()/deleteData()/deleteStream(), deleteSpaces, changeSchema, and TickDb::format() as destructive/irreversible. Confirm intent with the user before generating a call to any of them.
• LoadingOptions::writeMode set to REWRITE/TRUNCATE/REPLACE is also destructive. A default-constructed LoadingOptions() already defaults writeMode to REWRITE, not APPEND, so always set writeMode = WriteMode::APPEND explicitly for an ordinary write. Confirm the intended mode with the user before generating loader setup for anything else.

MCP-first workflow

When the task depends on live server context, follow the discovery order in `references/mcp-assisted-discovery.md` before generating field-access code. If MCP is unavailable, state what is missing and ask the user for stream/schema context before finalizing.

Capability map

• `references/workflow-selection.md`: routing table
• `references/mcp-assisted-discovery.md`: MCP discovery order
• `references/project-setup.md`: acquiring dxapi (Nexus archive, NuGet package), build integration, credentials, locating the right header for a given API
• `references/connection-and-lifecycle.md`: TickDb::createFromUrl, connection URI schemes, SSL and env vars, basic/OAuth2 auth, read-only mode, format()
• `references/cursor-and-streams.md`: TickCursor, select/createCursor, historical/live/reverse reads, stream creation (including createFileStream), multiplexed cursors, dynamic resubscription
• `references/loader-writes.md`: TickLoader, the register/begin/write/send cycle
• `references/message-types-and-decimal64.md`: positional DataReader/DataWriter field access, nullable/array/ASCII/CHAR/enum/TimeOfDay/interval/compressed-datetime/UInt40 fields, Decimal64/DFP conversions, MarketMessage base fields, typed codec pattern
• `references/stream-management.md`: listStreams/listEntities/listSymbols, InstrumentType/StreamScope, clear/truncate/purge/deleteData/deleteStream, renameInstruments, locking, periodicity, write buffering, other TickStream accessors, setSchema vs changeSchema
• `references/stream-spaces.md`: reading/writing/managing stream spaces
• `references/schema-introspection.md`: parsing stream metadata, schema-driven generic decode
• `references/schema-evolution.md`: TickStream::changeSchema, tracking background processes
• `references/qql-bound-queries.md`: parameterized executeQuery, compileQuery
• `references/topics.md`: TopicDB publish/poll pub-sub
• `references/debugging-and-performance.md`: acquisition, linking, connection, and runtime failures, protocol-version mismatches, cursor/loader throughput stats and preloading, the cursor/loader exception hierarchy, topic publish/poll failures, schema change failures