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

With no annotations supplied, the description properly discloses that this tool makes real network calls by enumerating the five HTTP probes, including anonymous and unauthorized variants. It also states the return shape at a high level ('findings with fixes'), which is meaningful for an agent choosing whether to invoke it. It does not cover latency, auth credentials, or side-effect caveats, but the core behavioral profile is transparent.

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?

Two sentences: the first front-loads purpose, the second adds exact probe names and the outcome. Every clause carries useful information; the enumeration is long but earned rather than padded.

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?

For a one-parameter tool with no output schema or annotations, the description covers purpose, operational behavior, and result type, which is enough to select and invoke it. The only real omission is a more detailed return contract or a link to list_scan_results, but that is a minor gap given the tool's simplicity.

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?

The input schema already documents the single url parameter at 100% coverage, including the streamable-HTTP qualifier. The description adds no parameter-specific meaning beyond implying that this URL is the target of the probes, so the baseline 3 applies.

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 uses a specific verb ('Diagnose') with a clear object ('whether an MCP server passes directory health checks') and then enumerates the concrete probes it runs. This clearly distinguishes the tool from the sibling list_scan_results, which is about reading prior results rather than actively running diagnostics.

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 intended trigger is clear: use this when you need to determine whether an MCP server passes the directory health-check suite. It does not, however, name the sibling list_scan_results or state when to prefer it, so the guidance stops short of explicit alternative routing.

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