mcp_diag

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description bears full responsibility for behavioral disclosure. It explains the two modes and what they involve (e.g., health checks tool registration, schema, directory writability; self-test creates sessions and verifies capabilities). While it does not discuss side effects or prerequisites, for a diagnostic tool the transparency is good, though it could be more explicit about potential state modifications.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is extremely concise: two sentences covering the tool's merged nature, the two modes, and their functions. No unnecessary words; every sentence provides essential information.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's moderate complexity (4 parameters, all documented), the description provides a clear overview of purpose and modes. However, it lacks information about return values or how to interpret results, which would be useful for a diagnostic tool. Overall, it is sufficiently complete for the task.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so baseline is 3. The description adds context for the mode parameter by explaining the two options, but does not elaborate on trace, headless, or sessionName beyond what the schema already provides. Thus, the description offers marginal added value over the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool is an MCP self-diagnosis tool that merges two previous tools. It specifies exactly what each mode does: health checks tool registration, schema, directory writability, and checkpoint; self-test creates sessions and verifies basic capabilities. This distinguishes it from siblings like mcp_health_check and mcp_self_test, which are now merged.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description mentions the merge of mcp_health_check and mcp_self_test, implying this tool replaces them, but it does not provide explicit guidance on when to use one mode over the other. An AI agent would benefit from recommendations on selecting health vs self_test based on context, but the description leaves that implicit.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.