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

Annotations already declare readOnlyHint and openWorldHint, so safety and open-world behavior are covered upstream. The description adds genuinely new context by enumerating returned fields and disclosing the cost ('1 credit'), but says nothing about result counts, pagination behavior, or rate/quota implications.

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?

Two compact clauses, with the payload (returned fields) front-loaded and the cost appended. No filler, though it is arguably too terse given the gaps elsewhere.

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, enumerating return fields is valuable and covers the return side. However, for a 6-parameter search tool with 50% schema coverage, missing details on pagination depth, result-per-page limits, and locale handling leave the agent with open questions.

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 50%, and the description mentions none of the six parameters — not query, page, language, country, location, or the advanced uule. It neither compensates for the undocumented parameters nor explains how location/country interact.

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 resource and result type: Google Images results with the returned fields (image URL, thumbnail, title, source page, size). Combined with the tool name it is clearly distinguishable from google_search, google_news and the shopping siblings, though it never explicitly contrasts with them.

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?

There is no guidance on when to use this instead of google_search or the other Google siblings, and no prerequisites or exclusions are given. The only usage-adjacent information is the credit cost.

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