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

Annotations already declare readOnlyHint=true, openWorldHint=true, destructiveHint=false. The description adds significant behavioral context: explains the paper trading simulation, execution costs, taker fees, rehearsal cost, and that it's not financial advice. This goes well beyond annotations to disclose data quality and limitations.

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 front-loaded with the core purpose and then provides necessary detail about granularity and execution model. While somewhat lengthy, every sentence adds value. It is well-structured but could be slightly more concise.

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 tool has 3 parameters, an output schema (indicated), and is a read-only data retrieval, the description fully covers what the tool does, its parameters, output format (date and usdValue for daily, cumulative for realized), and important context (paper trading, execution costs). No gaps.

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 baseline is 3. The description adds meaning by explaining the behavior of 'granularity' (daily returns one point per day, realized returns intraday points per event with cumulative total) and 'days' look-back window range and default. This enriches the parameter understanding, justifying a 4.

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 identifies the resource ('Wallet equity time series for the paper account') and verb ('Get'). It distinguishes from siblings by specifying it's for performance review over time and narrating results, distinct from get_portfolio or get_positions which are current state.

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 explains when to use: for reviewing performance over time and narrating results. It distinguishes between daily (standard) and realized (active intraday agents) granularities. It also states 'Paper trading only' and mentions the look-back window. While no explicit 'when not to use' or alternatives are listed, the context and granularity descriptions provide clear usage guidance.

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