Send a direct message

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

The annotations only note readOnly=false, idempotent=false, and destructive=false. The description adds critical behavioral context beyond that: the message is visible to a real person immediately and cannot be unsent from this tool. This is exactly the kind of irreversible side-effect disclosure that helps an agent avoid harmful actions.

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?

Two sentences with no filler: the first states the action and scope, the second conveys the irreversible consequence and the required precaution. Every sentence earns its place and the most important caution is 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 two-parameter tool with an output schema and clear annotations, the description covers what the tool does, the conversation scope, the irreversible nature, and the approval requirement. Nothing needed for safe and correct invocation is missing.

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 descriptions for both parameters ('Message text' and 'Conversation id'). The description reinforces that conversation_id refers to an existing conversation, but it does not add meaningful syntax or format details beyond what the schema already provides. A baseline of 3 is appropriate.

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 states a specific verb and resource: 'Send a message into an existing conversation as the authenticated account.' The word 'existing' clearly distinguishes this from repovive_start_conversation, so an agent can tell them apart without inspecting schemas.

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 clearly limits usage to existing conversations and adds a strong precondition: get the user's approval on the wording first because the message cannot be unsent. It does not explicitly name the alternative for starting a new conversation, but the context is clear enough to route the agent correctly.

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