download_media

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

The description discloses key behaviors: encryption handling, file writing, idempotency (confirms annotation), and that no notification is sent. This adds value beyond annotations, though it could mention potential failure modes.

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 concise (three sentences) and front-loaded with the main action. Every sentence adds value without redundancy.

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 the complexity of media download and decryption, the description covers prerequisites, output format (JSON fields), idempotency, side-effects, and path constraints. No output schema exists but return values are described.

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 coverage is 100%, and the description adds meaningful constraints: output_path must be under media root, default path behavior, and clarifies chat_jid format. This enhances understanding beyond the schema alone.

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 fetches encrypted media, decrypts it, writes to a local file, and returns the path. It distinguishes from siblings like send_file and list_messages by focusing on retrieval and decryption of cached media.

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 specifies the prerequisite (message must contain media) and directs to list_messages for finding media message IDs. It also notes idempotency and no notification. While it doesn't explicitly state when not to use, the context is clear.

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