outlook_categorize_message

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

Annotations already declare readOnlyHint=false, idempotentHint=true, and destructiveHint=false, so the description is not the only source of safety information. It does add real value by disclosing the overwrite semantics ("replaces the full list"), which is the single most important behavioral fact here. However it says nothing about whether unknown category names are auto-created, rejected, or silently ignored, which materially affects how the agent should construct the argument.

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 lines total, with the overwrite constraint front-loaded before the illustrative call. Nothing is padded, and the example is compact enough to earn its place as a parameter-shape demonstration.

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 two-parameter mutation with no output schema, the definition covers the core behavior but leaves out the return value and the validation/creation rules for category names. An agent can call it, but may produce wrong results if it passes new category names or omits existing ones, so it is adequate rather than complete.

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 carry the parameter burden. The inline example does clarify the shape of both parameters (a message_id string and a categories string array), which is better than nothing. It still leaves open the accepted format of message_id and the rules for category strings, so it only partially compensates for the coverage gap.

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 names a specific verb and resource ("Set categories on a message") and adds the crucial qualifier that the operation replaces the full list. It is clearly distinct from read/flag/move siblings, though it does not explicitly differentiate itself from outlook_reclassify_message.

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?

Usage is implied: because the operation replaces the full list, the agent can infer it must gather existing categories first, but this is never stated as a prerequisite. No mention of when to use this instead of outlook_reclassify_message, nor of outlook_list_categories as the way to find valid category names.

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