message_downloadMediaAsData

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

With no annotations, the description must carry the behavioral disclosure burden. It only mentions the operation and output type, omitting details about return format, error conditions, side effects, or read-only nature, which is insufficient for a download 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 one short sentence with no wasted words, and the '[Message]' prefix adds useful categorization without bloat. It is appropriately sized and front-loaded.

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 and no annotations, the description should explain the return value and any preconditions. It only says 'binary data', leaving ambiguity about how data is returned (e.g., base64, buffer) and what happens if the message has no media. It also fails to clarify how this tool differs from message_downloadMedia.

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?

All three parameters are fully described in the schema with examples and descriptions (100% coverage), so the description does not need to add parameter details. It adds no extra meaning beyond the schema, but the baseline of 3 applies.

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 states a specific verb ('Download') and resource ('attached message media') plus the output form ('as binary data'), which clearly distinguishes it from siblings like message_downloadMedia by indicating the data format.

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?

No guidance is provided on when to use this tool versus alternatives like message_downloadMedia, nor any prerequisites or context. The description only states the action without explaining selection criteria.

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