get_message_media

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

With no annotations provided, the description carries full disclosure burden. It discloses decryption behavior, return types per content type, and error handling for non-media. It does not mention rate limits or authorization, but for a download tool these are less critical. The promise 'never fabricated bytes' adds honesty context.

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?

Two sentences with dense information. The first sentence immediately conveys the main action. The second handles edge cases. Though the first sentence is long, no words are wasted. Efficient but could be split for readability.

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?

Despite no output schema, the description fully explains return values per media type, including error case for non-media. It covers all necessary behavioral aspects for a single message download tool with no missing critical details.

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. The description adds no extra meaning beyond the schema (e.g., format, constraints). Baseline score of 3 is appropriate as the description does not compensate further.

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 downloads and decrypts LINE media messages of any downloadable type, distinguishing it from siblings like get_message_image which likely handles only images. It specifies the verb 'download and decrypt' and resource 'LINE media message', covering the scope fully.

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 states that non-media messages return an error, guiding the agent to use it only for media. However, it does not explicitly compare to alternatives like get_message_image or provide when-not-to-use conditions, leaving some implicit guidance.

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