conversations_add_an_outbound_message

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

Annotations indicate readOnlyHint=false, meaning the tool mutates state, and the description's verb 'Add' is consistent. No contradiction found. The description doesn't disclose additional behavioral details like side effects, permission requirements, or the fact that it appends a call message to a conversation, but since annotations cover the mutability, the bar is lower. It adds minimal context beyond the annotations.

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 a single, terse sentence with no fluff—'Add an external outbound call'. It is front-loaded with the core action, but given the tool's complexity (7 parameters, nested objects), it is arguably too sparse to be adequately structured. It earns credit for brevity and clarity but lacks the substance needed for a helper description.

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 mutation tool with no output schema and only 3 annotations (none of which are rich in behavior), the description is severely under-specified. It doesn't explain what 'external' means, whether it creates a conversation message, how the 'call' object relates to the 'type' enum, or any side effects. The minimal annotation coverage leaves the description as the primary guidance, and it is insufficient.

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%—every parameter has a description in the schema, including the nested 'call' object and its subfields. The tool description adds no parameter-specific meaning beyond what the schema already provides. Since coverage is high, a baseline of 3 is appropriate, and the description doesn't compensate or enhance the schema details.

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 'Add an external outbound call' uses a specific action verb and resource, clearly indicating it creates a call record. It differentiates from the sibling 'conversations_add_an_inbound_message' by specifying 'outbound', but doesn't elaborate on what 'external' means relative to other messaging tools. The name suggests a message while the description says call, introducing slight ambiguity, but the overall intent is discernible.

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 no guidance on when to use this tool versus alternatives like 'conversations_add_an_inbound_message' or 'conversations_send_a_new_message'. It lacks any context about prerequisites, scenarios, or exclusions. While the name hints at outbound calls, there is no explicit routing or differentiation advice.

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