aircall_send_agent_message

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

Annotations only indicate readOnlyHint=false and destructiveHint=false, so the description carries some burden. It adds that the message appears in the Aircall Inbox and is for existing threads, but it does not disclose potential failure modes (e.g., thread not found) or side effects beyond what is obvious.

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 long, delivers the action and context upfront, and contains no filler or redundant information.

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 simple mutation tool with fully documented parameters, the description adequately covers the purpose and usage context. It could mention that the conversation must already exist or that this is intended for agent inboxes only, but it already says 'existing agent conversation thread.'

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 input schema has 100% coverage with descriptions for all three parameters. The tool description adds no parameter-level information, 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?

The description states a specific action ('Send a message') and a specific resource ('existing agent conversation thread'), with added context that it appears in the Aircall Inbox. This clearly distinguishes it from sibling tools like aircall_send_message by emphasizing it is for replying to ongoing conversations.

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 phrase 'Use this to reply to ongoing conversations' provides clear context for when to use the tool. However, it does not explicitly mention alternatives or when not to use it, so it slightly misses a full 5.

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