send_sms

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

No annotations are provided, so the description carries the full burden. It discloses the phone-number prerequisite but does not describe what happens if the contact lacks a number, delivery confirmation, or any side effects. This is a partial disclosure, scoring a 3.

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 two sentences, front-loaded with the action and resource. The example is concise and useful, with no redundant wording. Every part earns its place.

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 is simple, the schema is complete for its parameters, and the description includes the key prerequisite. It lacks error-handling details, but for a straightforward SMS send action, the description is sufficiently complete. A 4 is appropriate.

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 100%, so the baseline is 3. The description's example illustrates message content but adds little beyond the schema properties. It does not explain UUID format or contact resolution, but the schema already covers parameter meaning adequately.

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 the specific verb 'Send' with the resource 'SMS text message', making the tool's action unambiguous. The example ('Send John a text saying...') clarifies natural-language usage and distinguishes this tool from sibling contact-management tools like create_contact or get_contact.

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?

It clearly states a precondition ('The contact must have a phone number on file'), giving context on when the tool can be used. It does not mention alternatives or explicit exclusions, but the context is clear enough for an agent to decide when to invoke this tool.

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