send_group_dm

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

Annotations already indicate a mutating, non-read-only action (destructiveHint=true, readOnlyHint=false), and the description adds a useful True/False return contract. It does not discuss side effects, unfurling behavior, or optional fields, so the transparency is adequate but not rich.

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 compact and well organized: a one-sentence purpose, a short Args list, and a Returns line. Every sentence contributes, with no filler or redundancy.

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?

Even with an output schema present, a 5-parameter tool needs more context than this. Three optional parameters are unexplained, no guidance is given for selecting this tool over send_dm, and the failure behavior beyond 'returns False' is not described.

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 description adds meaning for user_ids ('2+ user IDs') and message ('message text'), but schema description coverage is 0% and the optional parameters blocks, unfurl_links, and unfurl_media are completely undocumented. With low coverage, the description needed to compensate for these gaps and did not.

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 opening phrase 'Send a message to a group DM' gives a specific verb, resource, and scope, and 'multi-party direct message' distinguishes this from ordinary DMs. It does not explicitly contrast with siblings like send_dm or post_message, so it falls just short of a perfect score.

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 requirement that user_ids must contain '2+' users implies this tool is meant for group conversations, giving some usage context. However, the description never states when to use this instead of send_dm for one-to-one DMs or post_message for channels, and it names no alternatives or exclusions.

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