search_inboxes

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

Annotations already establish read-only, non-destructive, non-open-world semantics, and the description adds material behavior the annotations cannot: per-account partial-failure handling ('a failing account is reported in its own entry without stopping the rest') and time-based skipping surfaced via not_reached, plus the pagination handoff through next_offset.

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?

Four short sentences, front-loaded with purpose and scope, followed by usage conditions, failure semantics, and the escalation path. No redundancy or filler.

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?

With no output schema, the description does useful work explaining return shape (per-account entries, not_reached, next_offset, account_id, mailbox_path). It is nearly complete, though the meaning of limit_per_account versus the first-page constraint is not spelled out.

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% across 4 parameters, so the description carries the burden. It explains query (empty lists everything) and unread_only behavior, but says nothing about scan_limit or limit_per_account, leaving half the parameters undocumented in both schema and text.

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 states a specific verb and resource plus scope: 'Search the inbox of every permitted account in one call: the first page from each.' It also differentiates itself from the sibling search_messages by naming it for deeper single-account work, so an agent can distinguish the two without opening either schema.

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 gives explicit when-to-use conditions ('Empty query lists messages; unread_only=true reviews what is new') and a concrete routing rule to the alternative tool ('To go deeper in one account, call search_messages with that entry's account_id, mailbox_path and next_offset'). Nothing about tool selection is left to inference.

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