send_image_as_user

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

Discloses internal wire format and auto-deriving of display sizing; no annotations present, so description carries burden. Doesn't cover permissions or error cases, but adds technical detail beyond schema.

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?

Three sentences with version header; front-loaded with identity but includes internal details. Could be trimmed slightly without losing meaning.

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?

No output schema, and description does not mention return values or success/error indicators. Adequate for usage but missing post-call behavior.

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?

Adds context: chat_id numeric preferred, thumbnail defaults to image_key, width/height/mime/size optional metadata. All parameters have schema descriptions, but description enriches them.

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 'Send an image as the logged-in user (NOT bot)' with specific verb and resource, and distinguishes from sending messages as bot or other file types.

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?

Explicitly requires image_key from a prior upload_image call, and explains thumbnail key defaulting. Does not explicitly list when not to use, but context implies user vs bot distinction via sibling tool names.

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