Get Base64 from Media Message

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

Annotations already declare readOnlyHint=true and destructiveHint=false, indicating a safe read operation. The description adds context that temporary URLs expire, implying this tool provides a persistent base64 result, but doesn't disclose additional behaviors such as output size limits or 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 two sentences, front-loaded with the primary purpose, and contains no redundant or verbiage. Every sentence earns its place, making it highly concise and well-structured.

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 tool's simplicity, annotations, and full schema coverage, the description provides sufficient context: it states the purpose, offers a usage alternative, and identifies the parameter source. It doesn't explain convert_to_mp4, but the schema covers that, so the overall completeness is strong.

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%, with both parameters already described. The description repeats the source of message_id (from find_messages results) but adds no new information about convert_to_mp4 or parameter formatting, so it contributes minimal value beyond the schema.

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 extracts media content as base64 from a WhatsApp message, using a specific verb and resource. It distinguishes itself from siblings like send_media (sending) and find_messages (searching) by focusing on the extraction/retrieval of 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 explicitly recommends using this tool instead of temporary media URLs, which expire quickly, and instructs to pass the message key ID from find_messages results. This provides clear context and a direct alternative, though it doesn't explicitly mention when not to use it.

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