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

Annotations already cover the read-only, idempotent, non-destructive safety profile, so the bar is lower. The description adds real value beyond that: the columnar shape of `created`/`spent`, the BTC unit of `supply`, and the set-reconciliation identity (set after first-1 + created - spent = set after last) which tells the agent exactly what the numbers mean.

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 the scope sentence, then return shape, then the reconciliation rule — each sentence carries information. It is dense but not padded; the only minor cost is that the reconciliation sentence takes a moment to parse.

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?

An output schema exists, so the description needn't enumerate return fields, and it still adds the key semantic rule for interpreting them. With one fully documented parameter and annotations covering safety, the only real gap is sibling disambiguation.

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 HeightOrDate anyOf, the YYYY-MM-DD pattern and the examples are already fully documented. The description restates the accepted formats but adds no syntax or constraint detail beyond the schema, so baseline 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: what a block height or UTC day 'changed in the UTXO set', and gives concrete input examples (840000, YYYY-MM-DD). It doesn't distinguish itself from nearby siblings like get_urpd or get_tx_outspends, so it stops short of a 5.

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 two supported query modes (single block vs whole UTC day) are implied clearly, which is useful context. But there is no explicit when-to-use guidance, no exclusions, and no routing to alternatives such as get_urpd or get_tx_outspends for related UTXO questions.

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