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

With no annotations provided, the description carries the full behavioral burden and does so thoroughly: it discloses magic-byte validation, full decode, normalization to 512x512 PNG, metadata stripping, private-address blocking for URL fetches, and that the operation is free. These details go well beyond the input schema and give the agent confidence about processing and side effects.

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 a single dense sentence with no wasted text. Important constraints and the downstream use are front-loaded, and every clause earns its place.

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?

For a two-parameter upload tool with no annotations and no output schema, the description covers validation, normalization, rejection rules, return values, and downstream usage. An agent has enough information to call it correctly and understand what will happen to the uploaded image.

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 already 100%, so the schema documents both imageUrl and imageBase64. The description adds meaningful constraints beyond the schema, such as accepted image formats, minimum dimensions, maximum size, and rejection behavior, though it does not explicitly map each constraint to a specific parameter.

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 and resource ('Upload a token picture') and adds precise scope: accepted formats, minimum dimensions, size limit, and rejection of SVG/HTML. It also names the downstream consumer ('pass to build_launch_tx'), making the tool's role clear relative to siblings like update_token_image and get_token_image.

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 gives clear usage context by explaining that the returned imageId and imageUrl are meant to be passed to build_launch_tx. It does not explicitly compare against alternatives such as update_token_image, but the intended workflow is clear enough for correct tool selection.

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