Loading ToolBench
A Swift implementation of the Model Context Protocol (MCP) server framework, enabling Swift applications to expose tools, resources, and prompts to language models
This is an SDK, not a production MCP server. The 4 tools shown (tools/list, tools/call, ping, initialize) are framework primitives, not domain tools. tools/list and tools/call have minimal but present descriptions and schemas. ping and initialize are lifecycle/protocol methods, not user-facing tools. No domain-specific tools are defined in the provided code. The Tool struct itself is well-designed with proper encoding/decoding, but the example tools lack depth: descriptions are generic protocol boilerplate (10-50 chars), parameter descriptions are minimal, and output schemas are not documented. Error handling is absent from the tool definitions. This scores as a framework foundation, not a production tool suite.
The initialization phase MUST be the first interaction between client and server. During this phase, the client and server establish protocol version compatibility, exchange and negotiate capabilities, and share implementation details.
The Model Context Protocol includes an optional ping mechanism that allows either party to verify that their counterpart is still responsive and the connection is alive.
To call a tool, clients send a `tools/call` request.
To discover available tools, clients send a `tools/list` request.
No domain-specific tools defined. Only framework primitives (tools/list, tools/call, ping, initialize) are shown. An SDK without example domain tools provides no guidance on how to build production-quality tools.
Tool descriptions are generic protocol boilerplate (10-50 chars). 'To discover available tools, clients send a tools/list request' does not explain WHEN to call it or WHAT it returns. Descriptions should be 50-200 chars and answer: what does it do, when to use it, what does it return.
Parameter descriptions are minimal or missing. 'cursor' in tools/list is described as 'Optional cursor for pagination' but does not explain format, expected values, or how pagination works. 'arguments' in tools/call is 'Optional arguments to pass to the tool', too vague.
Inferred effective spec: <=2025-11-25.
| Scored | Grade | Overall | Spec posture | Rubric |
|---|---|---|---|---|
| 2026-09-23 | F | 40 | <=2025-11-25 | v2 |
Output schemas are not documented. tools/list returns a Result struct with 'tools' and 'nextCursor' fields, but the schema is not visible in the tool definition. LLMs cannot plan downstream calls without knowing the response structure.
ping tool has no input schema visible. The description references the MCP spec but provides no actionable guidance for LLMs on when or why to call it.