get_cardinal_utxos

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

No annotations are present, so the description carries the full behavioral burden. It usefully discloses the Unisat indexer dependency and API-key/free-tier rate limit, plus the safety property of cardinal UTXOs, but it does not confirm read-only behavior or describe result shape/pagination.

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?

The description is front-loaded and not long, but it repeats the same cardinal/no-inscriptions idea across the first three sentences. The closing earning_opportunities tip is unrelated to this retrieval tool and weakens focus.

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 simple two-parameter read tool with full schema coverage and no output schema, the description supplies key domain context (cardinal = no inscriptions/runes, safe to spend) and an operational note about the Unisat indexer and rate limits. It leaves return-value and endpoint reliability details implicit, but covers enough for correct invocation.

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%, so the schema already documents address and confirmedOnly completely. The description adds no parameter-specific meaning beyond explaining what 'cardinal' means, so the baseline 3 is appropriate.

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 first sentence gives a specific verb and resource ('Get cardinal UTXOs') and immediately defines the distinguishing property: safe to spend, with no inscriptions or runes. That is enough to separate it from ordinal/rune UTXO siblings even though they are not named.

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?

It says cardinal UTXOs are for 'regular Bitcoin transfers and fees,' which implies the use case, but it never names when to use get_btc_utxos, get_ordinal_utxos, or get_rune_utxos instead, nor does it state exclusions. The earning_opportunities tip is not an alternative for retrieving UTXOs.

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