send_message

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

Beyond annotations (readOnlyHint=false, destructiveHint=false), the description discloses that mentions don't ping by default and that explicit mentions require discord_request. This is useful non-obvious behavior. It does not cover response shape or permission failures, but those are less critical for a simple send tool.

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 short sentences with no filler. The core action is first, followed by a naming/ping caveat, then a focused pointer to the alternative tool.

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 small 3-parameter tool with no output schema, the description plus schema provides enough to select and invoke it correctly. Missing details are a return-value description and explicit channel_id semantics, but neither blocks correct use given the self-explanatory parameter names.

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 property descriptions are absent, so the description must carry the semantics. 'Send a message or reply' maps content and reply_to, and the discord_request boundary implies content is plain text rather than attachments/embeds. However, channel_id is only inferred from the property name/title, and reply_to's behavior is not elaborated.

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 uses a specific action verb ('send') and resource ('message or reply'), and immediately clarifies an unexpected behavior ('Mentions do not ping by default'). This clearly distinguishes it from sibling discord_request while covering the core function.

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 second sentence explicitly routes alternative usage: 'Use discord_request for attachments, embeds, polls, components, or explicit mentions.' This gives concrete when-not-to-use guidance and names the sibling tool, leaving little to inference.

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