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

Annotations already declare readOnlyHint=true and openWorldHint=true, covering the safety profile. The description adds behavioral context by specifying the return payload ('Returns list of unspent outputs with tx hash, position, height, and value in satoshis'). It does not mention rate limits or errors, but given the simple read-only nature, this is sufficient. No contradiction with 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?

The description is two sentences, front-loaded with the core purpose and followed by the return format. Every word earns its place, with no redundant information. It is concise and well-structured.

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 read-only tool with one parameter and no output schema, the description covers the essential purpose, network, and return fields. It does not specify whether unconfirmed UTXOs are included, which could be a meaningful gap, but overall it is sufficiently complete for a straightforward query tool.

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% (the 'address' parameter is fully described with its allowed formats). The description does not add significant parameter-level detail beyond what the schema already states. The network context (testnet3) is useful but is more about tool purpose than the parameter's semantics.

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 clearly states the tool's function: 'Get unspent transaction outputs (UTXOs) for a Bitcoin address on Bitcoin testnet3.' It uses a specific verb ('Get'), identifies the resource (UTXOs), and distinguishes from the mainnet sibling by specifying 'testnet3'. It also mentions the return fields, adding precision.

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 clearly scopes the tool to Bitcoin testnet3, making it evident when this tool is appropriate (for testnet addresses). However, it does not explicitly name alternatives like 'btc_get_utxos' for mainnet usage, so it lacks explicit exclusions or 'when not to use' guidance.

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