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

With no annotations, the description must carry the behavioral burden, and it does disclose the underlying assumptions that shape results (FTMO 5% daily / 10% total drawdown, USD cost basis, monthly effective spread + commission). However, it never states that this is a pure computation with no side effects, nor that the panel of 8 brokers is hardcoded, nor what the output looks like — all relevant to a safe, correct call.

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?

Two sentences, front-loaded with what is compared and followed by the calculation methodology, with no filler. The parenthetical broker slug list (Pro/Zero/Raw, KIWAMI, Blade) is dense but does contribute scoping information.

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 is expected to say what comes back, and it names the three computed outputs (spread+commission cost in USD, swap-free carry savings, 0% stop-out survival buffer). It is adequate to call the tool correctly, though it omits the fixed-universe caveat and the shape of the comparison result.

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 description coverage is 100%, so all four parameters (symbol, lotSize, monthlyTrades, accountBalanceUsd) already carry defaults and explanations. The description adds no parameter-level meaning beyond the schema, so it sits at the baseline rather than earning credit.

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 names a specific verb (Compare) and an enumerable resource set (8 named FX/Gold ECN brokers plus named prop firms), and lists the exact metrics computed. It is far from tautological and clearly scoped to broker/prop-firm cost comparison. It stops short of 5 only because it never distinguishes itself from the adjacent sibling calculate_swap_carry_and_kelly_lot_size, which overlaps on swap/carry math.

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?

Usage is only implied by the content — an agent can infer it is for evaluating broker economics before choosing one. There is no explicit 'use this when...' clause, no statement about when the sibling cost/swap calculator is the better choice, and no exclusions (e.g., that the broker list is fixed and cannot be extended).

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