read_messages

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

Annotations already declare readOnlyHint=true and destructiveHint=false. The description adds useful behavioral caveats: pagination via the before parameter and that Discord may omit message content when credentials lack access or intent. No contradiction with annotations.

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 compact and information-dense. Both sentences add value: the first states the operation and key pagination pattern, the second states a constraint and a content-omission caveat. No wasted words.

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 five-parameter tool with no output schema, the description covers the read-only nature, pagination, parameter exclusivity, and a data-completeness caveat. However, it does not describe the expected return shape or the detailed semantics of after and around, leaving moderate gaps for an agent.

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%, so the description must carry parameter meaning. It clarifies before for pagination and imposes mutual exclusivity among before, after, and around, but it leaves after, around, limit, and channel_id semantics mostly to inference from parameter names.

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 a concrete action and resource: reading channel or thread history. It is distinct from single-message or search tools, though it does not explicitly name a sibling alternative such as search_messages.

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 gives concrete pagination guidance ('Use the oldest message ID as before for older pages') and explicitly restricts parameter combinations ('Only one of before, after, around may be supplied'). It does not explain when to prefer this over search_messages or get_message, but the usage context is clear.

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