balances

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

No annotations are provided, so the description carries the behavioral burden. It discloses that the tool performs a read-style query ('Show balances'), groups by account, and supports regex filtering. It does not explicitly state side-effect freedom or auth requirements, but the wording makes the query nature sufficiently clear.

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 concise sentences with no filler. The main purpose is front-loaded, and the parameter explanation immediately follows in the second sentence.

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?

With only one optional parameter and an output schema available, the description covers what the tool does and how to filter. It does not discuss edge cases like empty results or regex syntax details, but these are not critical for a tool this simple.

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 input schema only provides a type and default for account_filter, with 0% schema description coverage. The description fully compensates by explaining that account_filter is a BQL regex and providing concrete examples like 'Assets' and 'Expenses:Food'.

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 uses a specific verb and resource: 'Show balances grouped by account'. It clearly states the core behavior and the optional filtering. It does not explicitly distinguish itself from sibling tools like list_accounts or get_ledger, so it stops short of a 5.

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 usage context is implied: use this tool when you need balances grouped by account, optionally narrowed by a regex. However, it gives no explicit guidance about when not to use it or which sibling tool might be a better fit, such as list_accounts or run_query.

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