list_topics

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

No annotations are provided, so the description must carry the full burden. It states 'currently accessible,' implying real-time state. However, it does not disclose whether the list is exhaustive or filtered, or if there are any prerequisites (e.g., active connection). Behavioral details beyond the basic purpose are minimal.

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: the first states the purpose concisely, and the second provides an example. Every word earns its place; there is no fluff or repetition.

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 the tool has no parameters, no output schema, and a straightforward purpose, the description is sufficiently complete. It could optionally mention that the output is a simple list of topic names, but this is not essential for basic usage. The description adequately covers the tool's functionality.

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 input schema provides complete coverage. With 100% schema description coverage, the description does not need to add param info. The baseline for no parameters is 4, which is appropriate.

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 uses the specific verb 'Displays' and identifies the resource as 'a list of currently accessible ROS2 topics.' This clearly distinguishes it from sibling tools like echo_ros2_topic (which displays topic content) and get_topic_info (which provides detailed info).

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 includes an explicit usage example: 'Used when the user asks "What topics are available?"' This provides clear context for when to use the tool. While it does not explicitly mention when not to use it or list alternatives, the sibling list makes the differentiation evident.

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