Get Profile

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

Annotations already declare readOnlyHint=true, so the agent knows this is a safe read operation. The description adds the specific fields returned, which is useful context beyond the annotation. However, it does not disclose potential error conditions (e.g., invalid userId, user not found) or rate-limit behavior, which would be valuable for a read operation.

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, concise sentence that front-loads the main purpose and lists the returned fields. It is efficient and easy to parse, though it could be slightly more structured by separating the purpose from the field list. No wasted words.

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 read tool with one optional parameter and no output schema, the description is mostly complete. It covers what the tool does and what it returns. However, it lacks information about error handling, whether the userId must be a friend of the bot, and any authentication requirements, which are relevant for LINE API calls. The annotations cover the safety profile, but the description could be more 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 100%, so the schema already documents the userId parameter. The description adds the default behavior (defaults to DESTINATION_USER_ID) which is already in the schema's default field. The description does not add significant meaning beyond the schema, so baseline 3 is appropriate.

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 tool's purpose: retrieving detailed profile information for a LINE user, and enumerates the specific fields returned (display name, profile picture URL, status message, language). This is a specific verb+resource combination that distinguishes it from sibling tools like push_text_message or get_rich_menu_list.

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 fetching a user's profile but does not explicitly state when to use this tool versus alternatives. It does not mention exclusions or prerequisites, such as whether the user must be a friend or have consented. The context is clear enough for a simple read operation, but no explicit when/when-not guidance is provided.

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