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

Annotations declare readOnlyHint, idempotentHint, and non-destructive, so the safety profile is covered. The description adds valuable context: data source (mempool.space API), default network (mainnet), result limit (up to 50), and returned fields. It does not mention rate limits or API quirks, but this is a read-only operation with clear behavior. No contradiction.

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 every clause provides useful information: data source, network options, result limit, return fields, and use case. No wasted words.

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 an output schema present and annotations covering safety, the description provides a complete picture: what it does, data source, network selection, limits, return fields, and a typical use case. The tool is moderately simple, and the description adequately covers all dimensions.

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 67%: limit and network have descriptions, but address is undocumented in the schema. The description mentions network defaults and that the tool returns transactions for one address, but does not explain address format or semantics beyond an example. Since the schema covers most parameters and the description adds little beyond it, a 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 a specific verb (get) and resource (address transactions), and scopes it to 'recent Bitcoin transactions touching one address', distinguishing it from sibling tools like get_transaction (single transaction) and get_address (address details).

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 implies when to use it: 'Answers what a BTC address has been sending or receiving lately.' It also mentions reading from mempool.space API and network options, but does not explicitly state when not to use it (e.g., for historical data or full transaction details). Sibling differentiation is implicit through scoping, but no explicit alternatives are named.

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