get_account_balance_history

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

The readOnlyHint annotation already covers the safety profile, and the description adds useful scoping details like monthly granularity and single-account restriction. However, it does not disclose return format, pagination, or behavior for invalid/deleted accounts. This is adequate but not rich, matching the calibration where annotations carry the safety burden.

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, front-loaded with the core purpose, followed by a necessary prerequisite and an explicit alternative. Every sentence earns its place with no filler or redundancy.

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 single-account query tool with 100% schema coverage and a readOnlyHint annotation, the description is complete enough. It tells the agent what the tool does, what to call first, and when to use a different tool. No critical invocation information is missing.

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 description coverage is 100%, so the schema already documents account_type, account_id, start_month, and end_month with constraints and format rules. The description does not add parameter-level meaning beyond the schema, so the baseline of 3 is appropriate.

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 ('Get') and resource ('monthly balance history for a single account'), clearly differentiating it from broader or synced-crypto alternatives. It also explicitly names get_crypto_synced_balance_history as the tool for synced crypto, so an agent can distinguish it from siblings without opening the schema.

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 an explicit prerequisite: call get_all_manual_accounts, get_all_plaid_accounts, or get_all_manual_crypto first to discover ids. It also states a clear exclusion: use get_crypto_synced_balance_history for synced crypto holdings. This leaves little ambiguity about when to use this tool versus alternatives.

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