Broadcast Text Message

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

The annotation destructiveHint=true is reinforced and expanded by the description's explicit warning that the message goes to all followers, which is a significant behavioral consequence. This goes beyond the annotation by explaining the reach and potential impact. The description does not mention rate limits or response details, but for a broadcast action, the key behavior is covered. No contradiction with 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 two sentences with no filler. The main action is front-loaded ('Broadcast a simple text message via LINE to all users'), followed by a usage condition and a warning. Every sentence adds value, and the length is appropriate for the tool's simplicity.

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?

The description covers the core purpose, the usage condition (plain text), and the broadcast scope warning. It does not mention prerequisites like authentication, but that may be implicit for LINE API tools. It also lacks explicit mention of the alternative for targeted sends, but the 'all users' phrase covers that. Given the single nested parameter and lack of output schema, the description is mostly complete, with only minor gaps around explicit alternative routing.

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 description coverage is 0%, meaning the tool description must compensate for parameter meaning. The description only says 'simple text message' and 'plain text', but does not explain that the message parameter is an object with a required 'text' field and an optional 'type' constrained to 'text'. The schema itself does provide descriptions for the 'text' property, but the tool description adds no additional parameter-level guidance, leaving the agent to rely solely on the schema structure. This is a notable gap.

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 verb (broadcast), the resource (text message to all LINE followers), and the scope (all users who followed the Official Account). It also distinguishes from siblings by specifying 'plain text messages without formatting', which implies the existence of a flex alternative, and 'all users' which implies targeted sends. This makes the tool's purpose unambiguous and differentiates it from push_text_message and broadcast_flex_message.

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 explicitly says 'Use this for sending plain text messages without formatting', giving a clear condition for when to use it. It also warns 'Please be aware that this message will be sent to all users', which signals the impact and implicitly cautions against using it for targeted audiences. However, it does not name the alternative tools (e.g., push_text_message for targeted sends), so the guidance is helpful but not fully explicit about exclusions.

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