get_mailbox_unread_counts

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

The description explains the return structure and behavior of the summary_only flag, but without annotations, it fails to mention that this is a read-only operation, any idempotency, or potential rate limits.

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 brief and well-structured with Args/Returns sections. Every sentence adds value, and there is no redundancy.

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?

Given the moderate complexity (3 optional params, no required) and presence of output schema, the description covers the core behavior and return types. Missing details like error handling or account name format, but adequate for a simple read tool.

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?

With 0% schema description coverage, the description compensates well by explaining each parameter's purpose (account as filter, include_zero for zero-count inclusion, summary_only for aggregation). It adds context beyond the schema's type and default.

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 the tool gets unread counts per mailbox, with optional account filtering and summary mode. It distinguishes itself by mentioning it replaces the former get_unread_count tool.

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?

It provides context for when to use summary_only mode but does not explain when to use this tool over siblings like get_inbox_overview or get_statistics. No explicit exclusions or alternatives are given.

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