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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the description doesn't need to justify safety. It does add genuinely new behavioral context: results are ordered newest first, paging is cursor-based, and a time range can be supplied - all facts absent from the annotations.

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 short sentences that front-load the core action, then pagination, then a worked example - no filler and no repetition of the title. The example earns its place by showing valid syntax for the type parameter.

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 six-parameter, all-optional read tool with no output schema, the description covers the essentials: what is listed, filter modes, ordering, range, and pagination. The only shortfall is the dangling 'checkpoint range' phrasing that implies a parameter the schema does not expose.

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 100%, so the baseline is 3 and the schema already documents every parameter. The description adds only the ordering default and a sample invocation; it also mentions a 'checkpoint range' that has no corresponding parameter in the schema, which slightly muddies rather than clarifies parameter meaning.

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 ('List on-chain events') plus the two filtering modes (Move event type or package) and the ordering ('newest first'). This is unmistakable purpose, though no sibling tool is named to differentiate against (e.g., search, sql, or explain_transaction).

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 implies when to use it by giving both filter modes and a concrete example call, which helps an agent construct a request. However, it never states when to prefer this over siblings like search or sql, nor any exclusions, so the selection guidance remains implied rather than explicit.

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