listTextMessages

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

With no annotations, the description carries the full burden of behavior disclosure. It discloses the mandatory filter requirement and the 400 error for unfiltered calls, which are critical behavioral traits. It does not mention pagination behavior or sorting, but the schema already describes pagination parameters, so the description adds substantial value beyond the structured data.

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. The first sentence states the purpose concisely, and the second delivers the essential constraint and error behavior without redundancy. It is front-loaded and every word 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?

Given the schema's rich parameter descriptions and the absence of an output schema, the description fills the most critical gap: the mandatory filter requirement and the 400 error. It does not elaborate on filter combination semantics or pagination details, but for tool selection and invocation, the description provides sufficient context to avoid common failures.

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?

The schema covers all 12 parameters with descriptions, so the baseline is 3. The description adds semantic value by grouping several parameters as valid filters and explicitly stating that at least one is required. This clarifies a critical constraint not evident from individual parameter descriptions, elevating the score above baseline.

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's purpose: 'List text messages.' This is a specific verb+resource combination that distinguishes it from sibling tools like createTextMessage and getTextMessage. The additional note about FUB's filter requirement further clarifies the scope without ambiguity.

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 provides clear context by explicitly stating that at least one filter is required and that unfiltered calls return 400. This gives the agent a key prerequisite. However, it does not explicitly mention when to prefer this tool over alternatives like getTextMessage for single messages, so it lacks explicit when-not or alternative guidance.

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