utxo_block_data

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It does reveal credit costs per action and notes that actual credits are returned in response headers, which is useful. However, it never states that the tool is read-only, what the response structure looks like, whether pagination is supported, or any error behavior. For a data-retrieval tool with zero annotation coverage, this is a significant gap.

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 verbose and repetitive. It lists the actions in a bullet list, then repeats the same actions in the credits section with numbers for each blockchain. This duplication inflates the length without adding new conceptual clarity. The core purpose is front-loaded, but the long credit enumeration distracts from the essential information. A more concise format would present actions with their parameter requirements and omit the redundant credit table.

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?

With no output schema, the description should explain what each action returns, but it does not. It also fails to map actions to required parameters (e.g., that get-block-by-height requires blockHeight, list-latest-mined-blocks uses count/limit, etc.), though the schema provides that mapping. For a multi-action tool with 9 parameters and 6 actions, the description should offer a usage summary or examples. This is incomplete for an agent to correctly select and invoke the right action.

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?

The input schema already provides descriptions for all 9 parameters (100% coverage), so the baseline is 3. The description adds credit costs per action per network, which is extra contextual information but does not clarify the semantic meaning of parameters beyond the schema. It does not explain which parameters are required for each action beyond what the schema's 'required' field indicates.

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 description opens with a clear statement: 'Get UTXO block details (Block Data product).' It then enumerates six concrete actions with one-line descriptions, making it obvious what the tool does. The explicit list of UTXO blockchains (bitcoin, bitcoin-cash, etc.) differentiates it from siblings like evm_block_data and xrp_block_data, which cover other chains.

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 provides no guidance on when to use this tool versus its siblings (evm_block_data, xrp_block_data). It does not state 'use this for UTXO blockchains' or mention alternatives. The only contextual hint is the network list, which implies UTXO support but never states a selection rule. No exclusions or conditions are given.

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