send_message_to_sessions

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

The description states the main user-visible effect (pop-up message to active sessions), which is useful given there are no annotations. But it doesn't explain what happens for inactive/invalid sessions, whether the call is asynchronous, or any side effects beyond the notification. No contradiction with the input schema.

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?

One sentence, front-loaded with the action and object, and no filler or repetition. It is immediately scannable and conveys the core behavior efficiently.

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 notification tool, the description plus full parameter schema covers the essential context. It omits edge-case behavior (e.g., what happens with invalid/inactive session IDs) and does not mention any restrictions, but the tool is simple enough that this is not a critical gap.

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 already provides complete descriptions for all parameters (message, session_ids, message_type), so the tool description itself adds little semantic value. The description's 'active user sessions' phrase slightly reinforces session_ids but doesn't meaningfully extend beyond the 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?

The description uses a specific verb ('send') and a specific resource ('pop-up notification message' to 'active user sessions'). It clearly states the action and target, making it easy to distinguish from the many read/list operations in the sibling list.

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 phrase 'active user sessions' gives context about the intended audiencecars. However, there is no explicit guidance about when to use this tool versus alternatives, such as logging off or diagnosing sessions, nor any mention of when not to use it.

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