Break an account down by day, symbol and hour

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

Discloses response shaping: chart-sized payload, dropped running totals, at most ten symbols kept, hourly grid totalled across the window, and the use of `notes` to signal truncation. This is significant behavioral context far beyond the readOnlyHint/openWorldHint annotations, and it does not contradict any annotation.

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 paragraph is dense but every clause serves a purpose: purpose, use case, alternative, shaping warning, and parameter clarifications. It is front-loaded with the core breakdown, then practical guidance, and no filler words. The length is justified by the tool's complexity.

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's complexity, the description covers the main output structure (three series), the shaped/truncated behavior, the most important parameter pitfalls, and the recommended alternative tool. Combined with the rich schema and annotations, this leaves no major contextual gap for agent selection or invocation.

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?

Even though schema coverage is 100%, the description adds meaningful parameter semantics: explains that omitting `from`/`to` defaults to the last 30 days, that a narrower window is the remedy for truncated symbols, and clarifies that `reporting` is a currency code, not a reporting period. These go beyond the schema descriptions.

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 and resource: 'Break one MT5 account down three ways over a date window' and enumerates the exact breakdown series (day-by-day P&L/volume/notional, per-symbol P&L/deal-count, hourly P&L). It further differentiates from the sibling tool get_account_performance by explicitly stating that is for a single whole-account figure.

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?

Provides explicit use cases ('which symbol is losing me money', 'what hour do I trade worst') and explicitly names the alternative tool for whole-account performance. It also gives practical guidance on date window omission and using a narrower window to reveal cut symbols.

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