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

Annotations already mark the tool as read-only and idempotent, and the description adds substantial behavioral context beyond that: snapshot semantics, sync timestamp meaning, structured warnings instead of throws for credit accounts, consent failure causes, and upstream 5xx degradation. This gives an agent realistic expectations about freshness and error handling.

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 dense but every sentence adds operational value: core behavior, freshness caveat, sync guidance, credit-specific errors, and upstream failure behavior. It is front-loaded with the primary function before diving into caveats and alternatives.

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 read-only balance tool with one parameter, no output schema, and rich annotations, this description is exceptionally complete. It covers what data is returned, when it may be stale, how to refresh it, how errors surface, and what provider/consent failures mean. An agent has enough to call it correctly and handle outcomes gracefully.

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 0%, so the description carries the load. It explains that account_ids must be an array, shows a 1–50 count limit, and ties each requested id to a balance row. It does not specify the exact identifier format, but that is a minor gap given the overall clarity.

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 states the tool returns the latest available balance per account id with a specific GET endpoint. It distinguishes itself from transaction listings and sync operations by explicitly framing the balance as a snapshot anchored to the last upstream sync.

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 gives explicit guidance on when to use this tool versus alternatives: if the balance seems stale or inconsistent with openfinance_list_transactions, the agent should run openfinance_force_sync and re-read. It also explains error-specific recovery actions, such as reconnecting the bank for consent errors.

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