Mentions and replies to you, prioritised and marked replyable

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

Annotations already declare read-only and idempotent, so the description adds significant behavioral details: cost per item, sorting/prioritization logic, default filtering of unanswered items, side effect on relationship ledger, and a security note about third-party content. This far exceeds what annotations provide.

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 dense but every sentence contributes unique information: cost, functionality, related tools, prioritization, defaults, side effects, and security. The phrasing 'reply weight is the biggest realistic head' is cryptic and could be clearer, but overall it is efficiently structured.

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 read-only tool with two optional parameters, the description covers result contents, sorting, default behavior, side effects, cost, and security considerations. No output schema is provided, so the description fully compensates for expected return values. It is comprehensive for its complexity.

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 covers 50% of parameters (include_answered is described in schema). The description adds that items are 'unanswered by default', informing include_answered's default behavior, but does not clarify the 'max' parameter. At 50% coverage, the description partially compensates but leaves room for more parameter-specific guidance.

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 'Lists posts that @mention you or reply to you' with specific details like 'newest first' and author attributes. It distinguishes from siblings by emphasizing 'Owned read' and its role in the reply workflow, explicitly referencing the reply and people tools.

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 references 'the reply tool' and 'people tool' as related tools, indicating when to use them in conjunction. It provides context on replyability and side effects but stops short of naming alternative tools to choose instead, offering clear usage context without formal exclusions.

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