Get an account performance summary

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

Beyond the readOnlyHint annotation, the description adds useful behavioral context: the response is a fixed-size summary that does not grow with the window, and a null live block means the terminal was unreachable (not that the account is empty). It also clarifies the ambiguous reporting parameter. No contradiction with annotations.

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 concise yet dense, front-loaded with the core purpose, followed by a compact list of included metrics, then practical usage notes. Every sentence adds value—parameters, defaults, null handling, and a common pitfall—without fluff or redundancy.

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 summary tool with an output schema, the description fully covers what the agent needs to know: the exact metrics returned, the default time window, default currency, the accountId pitfall, and the meaning of a null live block. Given the low complexity (no nested objects) and rich schema/output schema, this is highly complete.

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 parameters are documented, but the description adds valuable semantic clarifications: accountId is the id field from list_accounts, NOT the login; reporting is a currency code (default USD), not a period; from/to are in UTC YYYY-MM-DD. This goes beyond the schema's descriptions and addresses likely user confusion.

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 states the tool's function: 'Summarize how one MT5 account has performed over a date window' and enumerates the specific metrics returned (net P&L, win rate, profit factor, etc.). It explicitly labels itself as 'the default tool for any performance question,' distinguishing it from sibling listing tools like list_deals and list_positions.

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 concrete usage guidance: default 30-day window when from/to are omitted, reporting is an ISO-4217 currency code not a period, and accountId must come from list_accounts (not login). It names the tool as the default for performance questions, implying alternatives for other needs, but does not explicitly mention when-not to use it or name sibling alternatives.

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