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

Goes well beyond the annotations by disclosing the delivery pipeline: message is stored in Portaur's inbox, exactly one email goes to the supplied address, and nothing reaches the person's phone until they confirm. It also states the return value (a handle for request_status) and hard boundaries, which an agent needs before triggering an open-world, non-idempotent send.

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?

Purpose first, then required inputs, then the usage gate, then side effects and return value. No sentence is redundant — each adds a distinct constraint or behavioral fact.

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?

With no output schema, the description still tells the agent what comes back (a request_status handle), and it covers the confirmation side effect, the recipient scope and the forbidden actions. Nothing needed to invoke this correctly 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%, so the baseline is 3, but the description adds real meaning: name/email/body are required and subject optional, and the email is where 'one confirmation email' goes. It also clarifies the name and email belong to the person being helped, not the agent.

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?

A specific verb+resource ('leaves a written message for a person at Portaur') with the acting perspective spelled out ('on behalf of the person you are helping'). It also fences itself off from siblings: 'never calls or texts anyone' distinguishes it from request_callback, and 'never quotes a price' from pricing_approach.

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?

'Use it only when the person asked you to contact Portaur' is an explicit inclusion condition, and the closing sentence enumerates what it must not be used for (no calls, texts, other recipients, price quotes). No alternative tool is named by name, which keeps it just short of a 5.

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