get_btc_balance

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

Annotations already provide readOnly, destructive, idempotent, openWorld hints. Description adds helpful context: uses mempool.space API, configurable via env var, and that testnet/signet are rejected. No contradictions.

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?

Single paragraph with essential information front-loaded. Every sentence adds value without redundancy.

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?

Complete for a simple read-only tool with full annotations and one parameter. Covers purpose, behavior, configuration, limitations, and expected output components.

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 covers address parameter completely (100% coverage). Description reinforces address types and adds behavioral constraint ('Phase 1 is mainnet-only'), which adds value beyond schema.

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?

Clearly states it fetches confirmed + mempool balance for a single Bitcoin mainnet address, lists returned data components, and differentiates from other get_btc_* tools by specifying single address. Includes address type restrictions.

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?

Explicitly says READ-ONLY, mentions mainnet-only limitation, and describes backend. Does not explicitly contrast with sibling tools like get_btc_account_balance, but the single-address scope is implicit.

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