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

With no annotations provided, the description carries the full burden. It discloses a key behavioral caveat: below a sample threshold, the figure is a static estimate marked 'insufficient-data', not a measurement. It also instructs users to say which one they are quoting. This is strong, but it does not fully describe the return format or other edge cases, so a 4 is appropriate.

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 two sentences, each well-chosen. The first states the primary function, and the second delivers a critical caveat and user guidance. There is no fluff or redundancy, and all content earns its place.

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 no output schema or annotations, the description covers the core purpose and the crucial reliability caveat (insufficient-data vs. estimate). It could be slightly more explicit about the successful output shape (e.g., fields and units), but for a simple read-only stats tool, it is reasonably complete. A 4 reflects this minor gap.

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 tool has zero parameters, so the description has no parameter semantics to add. The mention of 'basis' and 'status' likely refers to fields in the output rather than inputs. With 0 parameters, a baseline score of 4 applies, and the description does not need to explain parameter details.

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 what the tool does: it provides actual measured settlement delivery times per rail and per corridor, contrasting with a single advertised constant. This distinguishes it from sibling tools and specifies the resource and scope. The implicit verb (e.g., 'returns'/'provides') is clear from context.

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 gives clear context: use this when you need real measured times rather than advertised constants. It also tells users to check basis/status and to distinguish between measurements and estimates. However, it does not explicitly name alternative tools or provide exclusion criteria, so it stops short of a 5.

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