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

With no annotations, the description carries the full burden and does so: creator-only authorization, signature scheme, replay protection via nonce+issuedAt, non-destructive behavior ('old versions are kept'), and an explicit custody assurance ('never touches keys'). This is exactly the behavioral context an agent needs before invoking a mutation.

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?

Front-loaded with purpose, then the step sequence, then the safety note. Dense but nearly every clause carries information; the arrow notation is compact and readable.

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 exists, yet the description explains the key return value (the exact message to sign) and the overall flow. Minor gaps remain around token identifier format and error/validation behavior when the signature is invalid.

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 only 43%, but the description compensates by grouping parameters into the two calls (token+image source, then imageId+nonce+issuedAt+signature) and explaining that the first call returns the message to sign. It could still clarify what 'token' accepts (address vs symbol), which neither source states.

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?

States a specific verb and resource ('change a token picture') plus a useful scope note that it works even after Uniswap graduation. It references the sibling upload_token_image only indirectly through the imageId parameter, so an agent must infer the division of labor rather than being told explicitly.

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?

Explains the two-step flow clearly and names the precondition (only the creator wallet, via EIP-191 personal_sign). It does not explicitly say 'use upload_token_image first unless you have a URL/base64', leaving the choice of the alternative implicit.

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