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

Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false, openWorldHint=false), so the bar is lower. The description adds genuinely useful behavior not in the annotations: the draft is sourced 'with its sources' and the tool returns `data: null` when no draft exists, which tells the agent how to handle the empty case.

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 tight sentences, front-loaded with purpose and followed by the null-return edge case. No filler or restated schema content.

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 one-parameter read tool there is no output schema, and the description compensates with the null-result behavior and a hint about included sources. What the draft object looks like is still unspecified, but an agent has enough to call and interpret 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?

Schema coverage is 100% for the single conversationId parameter, and the schema even documents the `cnv_…` format and points at find_conversation. The description adds no parameter detail beyond that, so the baseline 3 applies.

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?

States a specific verb+resource ('Read Aide's current reply draft') and disambiguates the resource by explaining what a draft is ('the Copilot draft teammates see'), which separates it from list_messages/get_conversation. It stops short of naming a sibling tool to route against, so it is clear but not fully differentiated.

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 never says when to call this versus get_conversation, list_messages, or reply_to_conversation, nor any prerequisite such as obtaining conversationId first. The only implicit signal is the word 'current', which is not real usage guidance.

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