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

Annotations already indicate read-only, idempotent, and non-destructive behavior, which the description aligns with. The description adds behavioral context by explaining it fetches data from NOAA when given an ICAO code, and that it's for training only. It does not contradict annotations. The safety-relevant training limitation is a valuable addition beyond the 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?

The description is concise: three sentences, each packed with information. It front-loads the core function, then explains inputs and the output format, and ends with the critical safety disclaimer. 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 tool with two optional parameters and no output schema, the description is complete. It explains what the tool does, how to invoke it, what to expect, and adds the training-only safety caveat. Nothing appears missing for an agent to use it correctly.

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 schema has 100% coverage, with clear descriptions for both parameters: 'taf' expects raw TAF text, 'icao' expects an ICAO code and is used when taf is not given. The description reinforces this by stating 'Pass the raw TAF text or a 4-letter ICAO code...' and adds the constraint that either can be used. The description adds the context that these are alternative inputs, which is slightly beyond the schema, but the schema is already quite good.

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 a specific action (decode) on a specific resource (TAF) and describes the output (plain-English periods with flight categories). It distinguishes itself from the sibling decode_metar by focusing on TAF rather than METAR, and from other tools that don't decode weather data.

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 states when to use it: to decode a TAF into plain English. It also provides two usage modes: pass raw TAF text or use an ICAO code to fetch from NOAA. It explicitly states it's for training, not flight planning, which is a crucial usage boundary. However, it doesn't explicitly mention when not to use it (e.g., for METAR), but the sibling decode_metar makes that implicit.

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