kakao_get_attachment

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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is known. The description adds valuable behavioral detail: the return shape ({kind, name, size, path}), that photos/emoticons return a downscaled image (animated ones show first frame), and the failure condition when attachment.expired is true and saved_locally is absent. This goes beyond annotations without contradicting them.

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 tight paragraphs: the first states the action and the return format, the second covers edge cases and a recovery step. It front-loads the primary function and keeps details relevant. No filler or repetition; each sentence earns its place, though it could be slightly more compact by merging the failure condition with the return format.

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?

With no output schema, the description compensates by explaining the return JSON structure and the downscaled-image behavior. It also covers the likely failure scenario and a recovery action, which is essential for an agent to handle errors gracefully. The only minor gap is not describing the `index` parameter's role in the description, but that is already in the schema. Overall it is sufficiently complete for an agent to invoke correctly.

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 all three parameters with types, defaults, and examples. The description does not add parameter-level meaning beyond what the schema provides; it focuses on return behavior and failure conditions. This meets the baseline of 3 for full coverage, but no extra value is added to parameter semantics.

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 opens with a specific verb and resource: 'Fetch the photo, video, file, voice note or emoticon of a message.' It clearly distinguishes this from sibling tools (list chats, read messages, search, send) and adds a concrete precondition: only messages with an `attachment` field are fetchable. The scope is unambiguous and the tool's role is obvious even without reading the schema.

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 states when the tool is applicable ('Only messages that have an `attachment` field are fetchable') and provides failure guidance ('ask the user to open that message in KakaoTalk, then retry'). It does not explicitly name alternatives or contrast with siblings, but the sibling names (read_messages, search, etc.) make the attachment-specific purpose clear. The retry instruction is practical usage guidance.

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