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

With no annotations, the description carries the full burden for behavioral disclosure. It only reveals scope and ordering; it does not mention default limit, pagination, return shape, permissions, or how time/filter parameters affect results.

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 a single front-loaded sentence with no filler, stating scope and ordering efficiently. It is compact, though arguably too sparse for a tool with five optional parameters and no annotations.

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 tool with five optional parameters, no annotations, no output schema, and relevant siblings, the description is incomplete. It leaves out return format, pagination defaults, and the distinction between simple listing and searching or contextual retrieval.

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 coverage is high at 80%, with descriptions for chat, after, before, and from_me, plus limit constraints. The description adds little beyond reinforcing the chat parameter, so the schema appropriately carries the parameter semantics.

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: list messages, scoped to one chat or all chats, with newest-first ordering. It is clear and distinguishable in intent, though it does not explicitly contrast with siblings like search_messages or get_message_context.

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 tool's purpose is implied, but there is no guidance on when to choose this over search_messages, list_starred, or get_message_context. No exclusions, prerequisites, or alternative routing are provided.

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