Discord MCP Server

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It mentions the tool can 'create or get existing' a DM, implying idempotent behavior (no duplicate channels), but doesn't cover critical aspects like permissions needed, rate limits, error conditions (e.g., invalid user IDs), or what happens if the user is blocked. For a mutation tool (creating channels) with zero annotation coverage, this is insufficient.

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, efficient sentence that front-loads the core functionality ('Create or get existing DM channel with a user'). There is no wasted verbiage or redundancy, making it easy to parse quickly while conveying the essential action.

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?

Given the tool's complexity (a mutation operation with potential side effects), lack of annotations, and no output schema, the description is incomplete. It doesn't explain the return value (e.g., channel ID or object), error handling, or behavioral nuances like idempotency. For a tool that modifies state, more detail is needed to ensure safe and correct usage by 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?

The input schema has 100% description coverage, with 'userId' clearly documented, so the baseline is 3. The description adds no additional parameter context beyond what the schema provides (e.g., format examples, validation rules, or how user IDs are obtained). It merely implies the parameter's purpose without enhancing understanding.

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 action ('create or get') and resource ('DM channel with a user'), making the purpose immediately understandable. However, it doesn't explicitly differentiate from sibling tools like 'discord_get_dm_channels' (which likely lists multiple DMs) or 'discord_get_channel' (which might handle other channel types), leaving some ambiguity about when to choose this specific tool.

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 no guidance on when to use this tool versus alternatives. It doesn't mention prerequisites (e.g., whether the user must be a friend), exclusions, or comparisons to siblings like 'discord_get_dm_channels' for listing DMs or 'discord_send_message' for messaging without channel creation. This lack of context makes it harder for an agent to decide appropriately.

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