read_messages

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

With no annotations, the description must carry the behavioral load. It discloses read-only behavior implicitly ("Read") and the pagination model, but says nothing about required permissions (Discord needs Read Message History), rate limits, default result size, or what the returned messages look like.

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 sentence with no waste, and the pagination capability is front-loaded alongside the core purpose. Slightly terse given the tool's complexity, but nothing is padded.

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 5-parameter read tool with no annotations and no output schema, the description is minimal: it omits permission requirements and any sense of return shape. It is adequate to identify the tool but leaves gaps an agent would need filled.

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 100%, so before/after/around/count/channelId are already fully documented in the schema. The description's parenthetical merely names three parameters without adding syntax, mutual-exclusivity rules, or precedence guidance. Baseline 3 is appropriate.

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 ("Read message history from a channel") and scopes it to channels, which distinguishes it from read_direct_messages. It does not, however, explicitly differentiate itself from list_pinned_messages or any search-style sibling.

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 no when-to-use guidance and never names an alternative, despite siblings like read_direct_messages, list_pinned_messages, and get_message_attachments that an agent might confuse it with. Pagination guidance is present but that is parameter semantics, not usage routing.

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