List messages

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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is fully covered by structured data. The description contributes one genuine behavioral fact beyond that: results are returned 'newest first'. It says nothing about pagination limits or result volume.

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?

A single compact sentence with the scoping constraint and sort order front-loaded and no filler. It is efficient, though the terseness borders on under-specification for a tool with three parameters.

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?

An output schema exists, so return values need not be described, and annotations cover safety; the description still omits what a 'thread' contains and whether search spans folders or is scoped to the selected folder. Adequate but with clear gaps for an open-world listing 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?

Schema description coverage is 67% (page and search are documented, folder is not), which is below the high-coverage threshold where a baseline of 3 would apply. The description adds no information about any of the three parameters, so it does not compensate for the gap.

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 and resource ('List message threads'), plus scope ('in a folder') and ordering ('newest first'). It is clearly distinguishable from the singular sibling get_message, though it never names a sibling explicitly to reinforce that distinction.

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?

There is no guidance on when to choose this tool over get_message, find_documents, or a search-oriented alternative, and no stated exclusions or prerequisites. Usage is only weakly implied by the word 'List'.

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