Build LINE audience from user IDs

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

The description adds significant behavioral context beyond annotations: the 5-10 minute indexing period and status transitions (IN_PROGRESS to READY). It also notes regional gating. Annotations provide limited info (not readOnly, not destructive), so this description fills important gaps.

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 well-structured with a clear first sentence, bullet-pointed args, return type, region note, and example. It is not overly verbose, though the Thai example could be removed without loss. Each sentence adds value towards understanding the tool.

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?

Given no output schema, the description provides the return structure and covers key aspects: purpose, behavioral timing, region restriction, and an example. It lacks error handling details or what happens on failure, but for a creation tool with straightforward input, it is sufficiently complete.

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 75% (3 of 4 params documented). The description mostly repeats schema information (max length, max items, default) with minor additions like 'optional OA id' for the undocumented 'oa' parameter. The example adds context but does not significantly enhance parameter understanding beyond what the schema already provides.

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 it creates a new LINE audience by uploading user IDs or IFAs. It provides context about the indexing delay and the typical use case (CSV from Google Sheets). However, it does not explicitly differentiate from sibling line_build_audience_from_engagement, which is a close alternative.

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 implies usage for uploading user IDs and includes a region restriction note. However, it lacks explicit guidance on when to use this tool versus alternatives like line_build_audience_from_engagement. No when-not-to-use or prerequisite conditions are stated.

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