Send text message (write)

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

The description discloses the 'WRITE' nature and highlights compliance rules, which adds value beyond annotations. However, it does not detail side effects like conversation state changes or error scenarios.

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, front-loaded with 'WRITE', no wasted words. Efficiently conveys the core purpose and key constraints.

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?

The tool has no output schema, and the description does not mention return values or error handling. For a messaging tool, this leaves some gaps, but the essential input constraints are covered.

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?

With 100% schema coverage, the description adds minimal extra meaning. It provides a useful note for media_url (MMS) but otherwise does not enrich the parameter semantics 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 clearly states the tool sends an SMS/MMS reply in a conversation, using specific verbs and resources. It distinguishes itself from siblings by focusing on sending text messages rather than creating or updating other entities.

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 includes compliance requirements and a hint for MMS, but does not explicitly state when to use this tool over alternatives or when not to use it. It gives some context but lacks exclusions.

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