NEWS
mcplite 0.1.0 (2026-08-03)
- First release of the lightweight, tools-only Model Context Protocol (MCP)
server over standard input and output (stdio), supporting the MCP lifecycle,
ping,
tools/list, and tools/call.
- Supports protocol versions
2024-11-05, 2025-06-18, and 2025-11-25.
- Provides native tool and JSON Schema helpers, with optional interoperability
for compatible
ellmer tool definitions.
- Adds explicit protocol-native tool results through
tool_result() and the
content_text(), content_image(), content_audio(),
content_resource_link(), and content_resource() constructors. Results may
contain ordered mixed content, structured content, annotations, and metadata
while ordinary R return values retain their existing text conversion.
- Adds object-shaped
output_schema support to tool(). Tool definitions and
results follow the negotiated MCP version: structured output, output schemas,
audio, resource links, and content metadata are available for 2025-06-18
and later, with compatible fallback or contained tool errors for
2024-11-05.
- Handles protocol negotiation, request validation, JSON-RPC errors, and MCP
tool-call errors while keeping the stdio protocol stream usable.
- Automatically traces every envelope-valid MCP operation with one
OpenTelemetry server span, while keeping tool-authored child spans optional.
Standard
otel and otelsdk configuration owns provider and exporter
selection, remote W3C parent context is accepted through params._meta, and
request or tool content is not captured by default. Stdio servers must use a
stderr or remote exporter because stdout is reserved for MCP messages; with
no exporter configured, tracing is an effective no-op.