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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered; the description adds substantial context beyond that — result ordering, inclusion of sources, and a concrete cost model (50 free calls/day, then $0.01 USDC on Base via x402). It does not say what happens when the quota is exhausted or whether errors are returned, which keeps it out of the top band.

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, front-loaded with the use case, then what is returned, then cost. Every sentence carries information an agent needs and there is no 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?

For a read-only, three-parameter list tool with no output schema, the description covers what comes back (actions, due dates, sources), ordering, and payment terms. Only pagination/truncation behavior beyond the limit parameter is left implicit, which is a minor gap.

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 all three parameters are already documented with types, formats, defaults, and bounds. The description only restates date filtering and newest-first ordering without adding format or edge-case guidance (e.g. timezone handling for 'since'), so the baseline of 3 applies.

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 ('Lists regulator actions and due dates on compute derivatives') plus scope (since a date), ordering (newest first), and inclusion of sources. None of the sibling tools (prices, contracts, coverage) overlap with this, so an agent can select it on name and description alone.

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 opening sentence 'Use when you need what regulators have done about traded compute' gives a clear triggering condition. There is no explicit statement of when NOT to use it or which sibling to prefer for adjacent needs (e.g. market events vs regulatory actions), so it falls short of the top band.

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