Export an event window for Lichtblick / Foxglove

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

Annotations already include idempotentHint=true and destructiveHint=false. The description adds meaningful behavioral context beyond this: it writes files, auto-selects up to eight numeric plot curves, returns paths/curves/instructions, and does not launch a viewer. No contradiction with annotations.

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?

Three sentences carry all key information without fluff: purpose, alternatives, usage constraint, parameter hints, and limitations. The most important action is front-loaded.

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?

The description covers the core workflow, output nature, and viewer behavior, and the output schema covers return values. However, the meaning of path, topics, name, and args is not fully specified, so an agent may need to infer whether path is the output destination, a directory, or a file prefix.

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 0%, so the description must compensate. It clarifies units for start_seconds/end_seconds and explains the optional signals behavior and default auto-selection, but it leaves path, topics, name, and args semantics mostly implicit, which is a significant gap for a 7-parameter tool.

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 states a specific action ('Write a selected time window as JSON-encoded MCAP plus a plot layout') and clearly identifies the target viewers (Lichtblick or Foxglove). It distinguishes itself from byte-preserving native ROS/CDR export, which is meaningful given sibling export tools for other viewers.

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?

Explicitly tells the agent when to choose this tool ('Choose this for those viewers') and when not to ('not byte-preserving native ROS/CDR export'). It also gives practical constraints: inspect topic schemas, use source timestamps in seconds, and remember that the viewer is not launched.

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