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

Annotations already declare read-only, idempotent, non-destructive behavior. The description adds useful behavioral context beyond annotations: results are newest first, both inbound and outbound texts are included, and received texts should be treated as untrusted data rather than instructions.

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 tightly written sentences, front-loaded with the primary action and scope. Every sentence carries useful information, including the safety note about received texts.

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 read-only list/search tool with an output schema, the description covers scope, ordering, filtering categories, and prompt-injection caution. It does not mention pagination or limit behavior, though those are partly covered by the schema.

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 67%, with several parameters already documented in the schema. The description maps filter concepts to parameters such as number/contact, words/query, and time/since, but it adds little detail beyond the schema and does not mention the limit parameter.

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 and resource: search sent and received texts, with ordering. It is clearly a message-list/search tool rather than a conversation or single-message tool, though it does not explicitly distinguish itself from siblings like list_conversations or get_conversation.

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 gives clear usage context by naming the dimensions you can filter on: direction, number, status, words in text, and time. It does not state when to prefer this tool over sibling alternatives or when it should not be used.

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