iris_list_messages

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It clearly states the read-only nature ('Read-only (does not mark anything read)'), describes the return format ('Returns summaries with a preview'), and includes a security note about untrusted message text. It does not mention pagination or rate limits, but covers the critical behavioral traits for safe usage.

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 appropriately sized, with each sentence adding value. It front-loads the primary purpose, then read-only behavior, then parameter details, then return behavior and a security note. It is concise without being sparse, though 'recent' and 'newest first' are slightly redundant.

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?

The description covers the essential aspects: purpose, sorting, default folder, since format, return summary behavior, and a pointer to iris_get_message for full bodies. With an output schema present, it does not need to detail return fields. It could mention the default limit (25) or pagination, but overall it is sufficiently complete for a list 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?

The description adds meaning for folder (display name or well-known names, default Inbox) and since (ISO date/datetime with example), but leaves limit and unread_only completely undocumented. Given the low schema description coverage (0%), the description should compensate for all parameters; it only covers half, so it is partially effective.

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 exactly what the tool does: 'List recent messages in a mail folder, newest first.' It identifies the resource (mail folder) and the action (list), and distinguishes itself from iris_get_message by noting it returns summaries, not full bodies. This is specific and unambiguous.

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 provides clear context for when to use this tool (listing recent messages) and explicitly directs users to iris_get_message for full bodies, which is an alternative. However, it does not mention when to use iris_search_messages instead, leaving some ambiguity in the broader toolset context.

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