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

The annotations already flag this as a non-read-only, open-world, non-destructive action, but the description adds genuinely new context: messages are sent from the workspace's line, opt-outs are honored (so some sends may not deliver), and the call consumes credits. Missing are rate-limit behavior, error handling, and what a send failure looks like.

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 clipped clauses, front-loaded with what the tool does and followed by the two facts an agent most needs (opt-out compliance and cost). Nothing is padded, though the telegraphic style borders on under-specification.

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 two-parameter mutation with no output schema, the description covers the essentials an agent needs to decide and invoke, but it never says what the call returns (message ID, delivery status) or what happens if the recipient has opted out. Those gaps matter for a cost-bearing send action.

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 100%, with both parameters documented ('E.164 number' and 'Message'), so the schema does the heavy lifting. The description adds no further meaning about formatting, length limits, or multi-recipient behavior, so the baseline of 3 applies.

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?

"Text from the workspace's line" gives a concrete verb (text/send) and resource (SMS from the workspace line), which is specific enough to separate it from email or in-app messaging siblings. It doesn't explicitly contrast itself with the other outbound tools such as the sibling send tool, so it stops short of full differentiation.

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?

There is no statement of when to use this versus alternatives (e.g., email or the other outbound messaging tools), and no prerequisite or precondition guidance beyond the implicit need for a recipient and body. Usage must be inferred from the tool name alone.

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