Get messages in chat

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

Adds significant behavioral details beyond annotations: return format (messages, has_more, optional total_count), parameter constraints (mutual exclusivity), and thread_scope semantics. Annotations already mark readOnly and idempotent, but description enriches understanding.

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?

Three concise sentences covering modes, constraints, and return format. Front-loaded with purpose, no redundant information.

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 an output schema present and 10 parameters, the description sufficiently explains all key behaviors (browsing, searching, fetching by IDs, replies, date filters) and constraints (mutual exclusivity, thread_scope modes). No gaps.

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 has 100% coverage with detailed descriptions. The description adds value by summarizing modes and stating the mutual exclusivity constraint, which is a critical usage rule not explicit in individual parameter descriptions.

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 'Read or search messages in one chat' and lists distinct modes (browse latest, search text, fetch by ids, load replies), distinguishing it from global search (search_messages_globally) and write tools (edit_message).

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?

Explicitly warns 'Do not combine message_ids with query or reply_to_id' and describes when to use each mode. Lacks a direct cross-reference to sibling tools for when not to use, but the context (single chat vs global) is clear.

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