transit_status

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

Annotations already mark this as read-only, and the description adds meaningful context about the fallback behavior for unsupported systems. This goes beyond what annotations provide, though it doesn't detail response formats or other edge cases.

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 concise sentences, front-loaded with the operation and followed by supported systems and fallback behavior. No wasted words.

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 simple one-parameter tool, the description adequately covers the main purpose, supported systems, and fallback behavior. With no output schema, a bit more detail on return format could be added, but it is sufficient for selection.

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 coverage is 100%, but the description adds semantic value by clarifying which system IDs yield alerts versus arrivals data. This explains behavior based on the parameter value beyond the schema's simple ID list.

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?

Description clearly states the tool gets service alerts and incidents for a transit system, using a specific verb and resource. It distinguishes itself from sibling tools by listing supported systems and noting the fallback behavior for unsupported ones.

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 provides clear context by listing supported systems (bart, mbta, septa, wmata) and indicating that others return arrivals data instead. While it implies when this tool is appropriate, it doesn't explicitly mention alternative tools or exclusions for per-system alert tools.

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