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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds the underlying API mapping (GET /accounts/{account_id}), which is modestly useful context, but it discloses nothing about return contents, error behavior for unknown ids, or auth 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 short sentences with zero padding, and the purpose is front-loaded ahead of the API reference detail.

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 one-parameter read tool with no output schema, the definition covers what the tool does, the identifier it needs, and the endpoint it maps to. The only real gap is the shape of the returned account object, which is a minor omission given the standard pattern.

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% and the single parameter already carries its own description with an example format ('account_...'). The description's 'by id' adds no meaning beyond the schema, so the baseline 3 is correct.

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?

States a specific verb and resource ('Retrieve a single bank account by id'), and the word 'single' implicitly distinguishes it from increase_list_accounts. It does not explicitly name the sibling it is not, nor contrast with increase_get_account_balance, so differentiation is inferred rather than stated.

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 phrase 'by id' implies the tool is used when an account_id is already known, which is a usable signal, but there is no explicit when-to-use/when-not guidance and no routing to alternatives such as list_accounts or get_account_balance.

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