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

The description adds substantial behavioral context beyond the annotations: notifications go to every verified owner, task_id groups updates into one email thread, daily-digest owners are queued until flush, and the body is a status note rather than a prompt. These are important side effects not captured by readOnlyHint/idempotentHint/destructiveHint.

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 front-loaded, with the core action in the first sentence. Each subsequent sentence—thread grouping, digest queueing, and body nature—earns its place by conveying behavior an agent needs before invoking.

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 notification tool with no output schema, the description covers the essential behavior: recipients, update kinds, thread grouping, digest delays, and body semantics. It does not describe optional parameter usage or any return/error behavior, but the required-call semantics are 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?

Schema description coverage is only 25%, so the description must compensate. It adds meaning for the required parameters: kind enumerates the update types, text is a 'status note, not a prompt,' and inbox_id maps to 'every verified owner.' It also clarifies task_id threading, though optional parameters like links, title, and client_id remain unexplained.

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 action: 'Send a progress, done, needs_input, or error update to every verified owner of the inbox.' This clearly identifies the resource (inbox owners), the verb (send/notify), and the update kinds. It also distinguishes itself from message-sending siblings by noting the body is 'a status note, not a prompt.'

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 implies when to use the tool—when sending progress/done/needs_input/error updates to inbox owners—and adds a useful exclusion: 'not a prompt.' However, it never explicitly names alternatives like cooper_send_message or states when those should be used instead, so the guidance is implied rather than explicit.

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