get_account_balance_history

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

The annotation readOnlyHint=true already signals a safe read operation, lowering the bar. The description adds useful context about prerequisite discovery calls and the alternative for synced crypto, but does not disclose additional behavioral traits like pagination, return format, or handling of deleted accounts. This is a modest but not rich contribution.

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 action, then prerequisite and alternative. Every sentence earns its place with no redundant phrasing.

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 relatively simple read-only tool with a well-specified schema, the description covers the main purpose, prerequisites, and a clear alternative. It does not explain the 'deleted' account type or month format, but these are already documented in the schema. The only minor gap is a lack of mention that account_type 'deleted' exists, but this is not necessary for the primary use case.

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%, with all four parameters described in the input schema. The description does not add parameter-specific semantics beyond mentioning that accounts must be discovered first, which relates to account_id. This matches the baseline 3 for high schema coverage.

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 opens with a specific verb+resource: 'Get monthly balance history for a single account.' It clearly distinguishes from the synced crypto alternative by name, making the tool's scope obvious. This meets the 5 criteria for specific and differentiated purpose.

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?

Explicit guidance is given: call get_all_manual_accounts, get_all_plaid_accounts, or get_all_manual_crypto first to discover ids, and use get_crypto_synced_balance_history for synced crypto holdings instead. This directly addresses when to use and when not to use the tool.

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