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

No annotations are provided, so the description carries the full burden of behavioral disclosure, and it supplies none. It does not say whether the tool is read-only, what it returns (no output schema either), whether the error text is stored or transmitted, or how results should be interpreted. The word 'diagnostic' hints at analysis but discloses no actual behavior.

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 short, but its brevity reflects under-specification rather than tight writing. There is no front-loaded statement of purpose or return value, only a namespaced echo of the tool name.

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 diagnostic entry point with no annotations and no output schema, the description should at minimum explain what a diagnosis produces and how to act on it. Instead it leaves the agent with only a name and a single documented input, which is not enough to call the tool confidently.

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 'errorText' parameter is fully documented in the schema ('Sanitized error or log excerpt'), so the schema already does the work. The description adds nothing about the parameter, but the baseline of 3 applies when the schema is self-sufficient.

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 is essentially the tool name plus a parenthetical category tag ('diagnostic'), which amounts to a tautological restatement rather than an explanation of what the tool does. It gives no indication of what 'diagnosing a runtime' actually means or how it differs from siblings like fix.suggest or shared::runtime.readiness.diagnose.

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 usage guidance whatsoever: no statement of when to call this tool, no prerequisites (e.g. a failing build, a runtime error), and no mention of the many sibling alternatives such as fix.suggest or runtime.readiness.diagnose that an agent would need to disambiguate against.

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