discord_send_message

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

Discloses permission requirement and return value ('Returns the new message ID'). Annotations already indicate a write operation (readOnlyHint=false), but description adds useful context beyond structured fields.

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 efficient sentences with no extraneous content. Purpose, differentiation, permission, and return value are front-loaded.

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 simple tool with two parameters, the description covers purpose, usage guidance, permission, and return value. No output schema exists, but return value is mentioned.

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 100% with clear descriptions for both parameters. Description adds only minor context ('plain-text body', max 2000 characters) but does not significantly extend beyond schema.

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?

Clearly states 'Send a plain-text message to a channel or thread.' and distinguishes from siblings by explicitly naming alternatives: 'For rich content... use discord_send_embed; to attach a reply reference... use discord_reply_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 defines when to use this tool vs. alternatives (rich content, reply reference) and states required permission: 'Requires the bot to have the Send Messages permission.'

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