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 transparency beyond annotations by specifying the return shape ('list of transactions with heights and tx hashes'), which is valuable since there is no output schema. It does not mention any potential limitations (e.g., only confirmed transactions), but it adds meaningful context.

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 long, with the first sentence stating the primary purpose and network, and the second sentence detailing the return value. Every word earns its place; there is no redundant or extraneous information.

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, single-parameter read-only tool with full schema coverage and readOnly/openWorld annotations, the description covers the essential pieces: what it does, the network, and what it returns. Given no output schema, the description fulfills the need to explain the return shape. It could add minor details (e.g., whether results are confirmed only), but it is still highly useful.

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% for the single parameter 'address', which is already well-documented with a description of accepted Bitcoin address types and length constraints. The tool description does not add additional parameter semantics beyond what the schema provides, so the baseline of 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 description clearly states the action ('Get transaction history'), the target resource ('Bitcoin address'), and the network ('Bitcoin testnet3'), which distinguishes it from the sibling tool btc_get_history (implied mainnet). This is a specific verb+resource+scope combination that leaves no ambiguity.

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 explicitly names the testnet3 environment, making the intended use case (testnet transactions) obvious. While it does not explicitly recommend against using mainnet tools or name btc_get_history as an alternative, the network qualification provides clear contextual guidance for tool selection among the sibling tools.

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