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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description reinforces this ('Reads or computes only and changes nothing'). It adds context annotations cannot express: pricing ($0.01/call, first 25 free), that failed/404 calls are free, and that repeat calls are charged — which explains the otherwise puzzling idempotentHint=false.

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, return fields, then routing, then billing, then a safety note — good ordering. Slight redundancy between 'Price $0.01/call ... failed calls free' and 'each call is charged, so repeats are not free', but the billing facts are decision-relevant rather than filler.

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, and the description compensates by enumerating every returned field. With a single optional parameter, no nested objects, and clear error and cost behavior, an agent has everything needed to call this correctly.

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 100% and the schema already documents number as 'Block number, or latest (default)'. The description adds the meaningful format detail that the value is a decimal number (versus hex, a real ambiguity for block identifiers) and supplies an example value.

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 ('Latest block number and block details on Ink, or any block by decimal number') and enumerates the returned fields (hash, timestamp, tx count, gas used/limit, base fee, producer). It is clearly separable from ink_gas and ink_tx in a large sibling set.

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 routes usage: 'Use for timestamps and confirmation counts; for current fees use ink_gas', naming the alternative and the condition that selects it. It also covers the missing-block case ('returns 404, uncharged') and gives a concrete invocation example (number=latest).

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