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

No annotations are provided, so the description carries the full behavioral burden, yet it discloses nothing: not whether the call is read-only, what it analyzes, whether it needs network access, or what kind of output it produces. The only substantive hint is platform scoping via the aliases, which is minimal for a diagnostic tool.

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?

It is a single short line, so it is not bloated, but a large portion is namespace boilerplate and an alias list rather than useful description. Reasonably sized yet front-loaded with metadata instead of the tool's behavior.

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?

With no output schema and no annotations, the description would need to explain what the diagnosis returns and any constraints, and it does nothing of the sort. For a tool whose whole value is interpreting an error excerpt, an agent is left guessing about the outcome.

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% and the single parameter (errorText) is fully documented in the schema as a sanitized error or log excerpt. The description adds no format, length, or usage detail beyond that, so the baseline of 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 restates the tool name plus "(diagnostic)" and a namespace prefix, giving no specific verb+resource explanation of what runtime diagnosis actually performs. It does not distinguish this tool from close siblings such as swift::fix.suggest, swift::env.preflight, or shared::runtime.diagnose, so the agent cannot tell them apart from the text alone.

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?

There is no when-to-use guidance, no prerequisites, and no mention of alternatives. The alias keyword list (apple, ios, ipados, macos, swift, swiftui, uikit) only signals platform targeting, not the conditions under which an agent should pick this tool over env.preflight or fix.suggest.

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