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

With no annotations, the description provides important behavioral details: fixed pricing regardless of account existence and no free-trial allowance. This informs the agent about billing implications beyond basic functionality.

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 moderately concise but includes a long second sentence with detailed pricing logic that could be shortened without losing meaning.

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 tool with 6 parameters, no output schema, and no annotations, the description covers only pricing context. Missing parameter explanations and return value information make it incomplete.

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 description does not explain any of the 6 parameters (nonce, account, signature, etc.) despite 0% schema coverage. The agent must rely solely on parameter names, which may be insufficient.

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 indicates it retrieves the balance of a single account. It distinguishes from sibling tools like list_accounts (listing) and get_balance_sheet (full report), but does not explicitly use a verb like 'get' in the first sentence.

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 mentions when to use (single account balance) and contrasts pricing with list_directives, but lacks explicit guidance on when not to use or alternatives for other scenarios like batch lookups.

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