send_message

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

With no annotations at all, the description carries the full load and does disclose genuinely non-obvious behavior: it is a mock, messages route to the outbox rather than the recipient, and replies are scripted later. It stops short of stating permissions, whether resending duplicates a message, or how claim_id affects delivery, which are gaps for a write tool.

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?

Three short sentences, zero waste, and the leading parenthetical "(Mock)" plus the routing statement are front-loaded before the follow-up hint. Every sentence contributes distinct information.

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 four-parameter write tool with no annotations, no output schema, and 0% schema coverage, the description adequately covers delivery semantics and the reply loop but leaves the meaning of subject and claim_id, error conditions, and return values entirely unaddressed.

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 0%, so the description must explain all four parameters, and it does not. "Email an employee" maps only loosely to `to`, and `subject` and especially `claim_id` (which implies linking the message to a claim) are never explained anywhere.

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?

States a specific verb+resource ("Email an employee") and gives a concrete use case (asking for a missing receipt), which tells an agent exactly what the tool does. It also names where the message lands (outbox) and points to search_inbox for the follow-up, so it is distinguishable from sibling read tools without opening a schema.

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?

Provides a clear usage context ("e.g. to ask for a missing receipt") and an explicit follow-up path: replies arrive in the employee's mailbox, so check with search_inbox. It lacks an explicit when-not clause or a statement about alternatives such as draft_decision, but the operational guidance is concrete.

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