create_message

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

With no annotations, the description must disclose behavioral traits. It mentions the write nature and the gating condition, adding value beyond the tool name. However, it does not describe potential failure modes, rate limits, or side effects, leaving room for more transparency.

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 a single, well-structured sentence that front-loads the most critical information (write gate and action). Every part adds value, with no redundant or verbose content.

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 2-parameter tool with an output schema, the description is nearly complete. It covers the purpose, a key usage constraint, and the access gate. It could mention prerequisites like valid channel ID, but that is largely implied, making it sufficiently complete.

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?

The schema has 0% coverage, so the description must compensate. It provides meaningful constraints for 'content' (non-empty, max length 2000) but does not explain 'channel_id' beyond its obvious name. Partial compensation, but one parameter remains implicit.

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 the tool's action ('Post a message to a text channel') with a specific verb and resource. It is unambiguous and distinguishes itself from sibling tools, which are all channel/role management operations.

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 provides clear usage context, including the write gate (DISCORD_MCP_ENABLE_WRITE=1) and the content limit constraint. It does not explicitly mention alternatives or when not to use it, but given the sibling list, no alternative exists for sending messages, and the context is sufficient.

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