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

Annotations already cover read-only, idempotent, non-destructive behavior. The description adds useful context: address formats supported and a degraded=true response under index load for ultra-active addresses, though it does not discuss authentication or rate limits.

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 compact and front-loaded. Purpose, usage, exclusions, return fields, address support, and the degraded-response edge case are all presented efficiently without filler.

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?

There is no output schema, but the description explicitly lists returned fields: address, confirmed/unconfirmed balance, utxo count and total, tx count, and last 10 transactions. For a one-parameter read tool, this is complete enough to invoke correctly.

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 single address parameter is already well documented. The description adds meaningful detail by listing supported Bitcoin address encodings (P2PKH, P2SH, bech32, bech32m), which helps an agent validate inputs.

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 returns balance and activity for a Bitcoin address and notes that no key is involved. It distinguishes this from btc_get_transaction by explicitly directing single-payment lookups there.

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 gives explicit when-to-use cases: reconciling a merchant wallet and checking whether an address received funds or how active it is. It also states what not to use it for and names the sibling tool to use for a single payment.

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