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

Annotations already declare readOnly and non-destructive, and the description adds substantial behavior beyond them: close-day bucketing in the journal timezone, open positions counting toward any window reaching today, compare's 'previous' window semantics, and the meaning of null metrics (profitFactorIsInfinite). The OAuth requirement is also disclosed.

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?

Front-loaded with purpose then progressively narrower detail on windowing and alternatives. The long metric enumeration is verbose but earns its place as de-facto return-value documentation in the absence of an output schema; still, it is a dense run-on that could be trimmed.

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?

With no output schema, the description compensates by enumerating the returned metrics, the timezone/close-day logic, null-metric handling, window defaults, comparison behavior, and the auth prerequisite. An agent has everything needed to call and interpret the tool.

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, but the description adds runtime meaning the schema lacks: the 30-day default, that range:'all'/'from'/'to' widen the window, and the timezone/override behavior. It reinforces 'accounts' as the scope selector, though it doesn't detail every parameter.

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?

Opens with a specific verb+resource ('The journal dashboard in one call for a window') and enumerates exactly what it returns: performance metrics, Edge Score components, per-day P&L, equity curve, open positions, and the accounts/settings covered. It also explicitly names the siblings it is not (journal_breakdown, journal_list_trades), so an agent can distinguish it without reading schemas.

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?

States when to use alternatives: 'Use journal_breakdown for where the P&L comes from and journal_list_trades for the trades themselves.' Adds default behavior ('Defaults to the last 30 days'), how to widen ('range: all' or explicit from/to), and a prerequisite (LuxAlgo OAuth sign-in). Nothing about tool selection is left to inference.

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