Get a Cardano address balance

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds two genuinely new behavioral facts: the BLOCKFROST_PROJECT_ID requirement and the fact that unseen addresses return zero balance. This goes beyond annotation coverage and helps the agent anticipate side effects and requirements.

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?

Two sentences, no filler. The core action is front-loaded, followed by the read-only nature, the environment requirement, and the notable zero-balance behavior. Every clause earns its place.

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 one-parameter read tool with readOnlyHint and openWorldHint already provided, the description covers the essential usage requirements (env var, zero-balance edge case). It does not describe return format or error handling, but with no output schema and a trivial operation, that is a minor gap. It is adequate for an agent 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?

The schema covers the single parameter fully with its own description ('Bech32 Cardano address (addr1... / addr_test1...)'). The tool description does not add anything beyond the schema for the parameter, so the baseline of 3 applies. It correctly points to the address parameter but adds no new syntax or format details.

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 states a specific verb ('Read') and a clear resource ('ADA and native-asset balance of a Cardano address from Blockfrost'). It unambiguously distinguishes this from sibling tools like get_venue, get_quote, or open_cdp, which target different domains. No ambiguity remains about what this tool does.

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 (for reading balances) and provides practical context: it requires BLOCKFROST_PROJECT_ID and explains the zero-balance behavior for unseen addresses. It does not explicitly exclude alternatives, but siblings are so different in purpose that no confusion is likely. It clearly frames this as a read operation.

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