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

No annotations are provided, so the description carries the burden. It discloses what the tool does and does not do, which is good behavioral transparency. However, it doesn't describe side effects, return format, or any operational behavior beyond being informational. It's a read-only conceptual tool, but that's not explicitly stated as a behavioral guarantee.

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 a single sentence, but it's packed with useful information: what it explains, what concepts it covers, and a usage directive. It's front-loaded with the core purpose. It could be slightly more concise, but it earns its length by covering the key aspects.

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 zero-parameter, no-output-schema informational tool, the description is quite complete. It tells the agent what the tool covers and when to use it. The only minor gap is not explicitly stating that it returns no data or that it's purely educational, but the description implies this strongly.

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 schema is trivially complete. The description doesn't need to explain parameters. Baseline for 0 params is 4, and the description adds context about what the tool covers, which is 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 clearly states the tool's purpose: it explains how sourcing works, what capacity bands and fuel types mean, and what the service does/does not do. It's a conceptual/reference tool rather than a data-fetching tool, which is a specific enough verb+resource. However, it doesn't explicitly distinguish itself from its siblings (get_bus_category, list_bus_categories), though the content described is clearly different.

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 explicitly says 'Read this before telling a buyer what to expect,' which gives a clear when-to-use directive. It doesn't explicitly mention alternatives or when not to use it, but the context is clear: it's a prerequisite reading before using buyer-facing guidance. The sibling tools are category-related, so the usage context is reasonably distinct.

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