Create Account Balance

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

Annotations declare readOnlyHint=false, idempotentHint=true, and destructiveHint=false; the description expands meaningfully on each. It explains the direct write side effect on balance history, the idempotent upsert behavior, the date omission default, and the currency limitation. No contradiction exists.

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?

Three short, well-organized paragraphs front-load the core purpose, then cover side effects and a currency caveat. There is no filler; each sentence contributes operational knowledge an agent needs.

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?

Given the 100%-covered schema, existing annotations, and output schema, the description covers the remaining operational essentials: which data it affects, idempotent update behavior, date semantics, and currency constraint. An agent has enough information to select and call this tool correctly.

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%, so the baseline is 3. The description adds value beyond the schema by explaining the currency context—recorded in the account's own currency with no separate currency accepted—and the semantic of omitting date to set today's balance, supplementing the schema's 'defaults to today.'

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 'Set an account's balance for a specific date in its balance history,' which gives a clear verb and resource. It further differentiates from read siblings by stating it writes directly to the balance-history series consumed by get_account_balances and get_portfolio_holdings, and explicitly says it is 'not the same as the account's summary balance field.'

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 tells the agent this is the write path for balance-history entries and contrasts it with the summary balance field, implying when not to use it. It also gives practical guidance: re-calling with the same account and date updates rather than duplicates, and omitting date targets today. It doesn't name a specific alternative like transfer_account_balance, but the context is sufficient.

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