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

Goes well beyond the readOnly/idempotent annotations: what the engine models (fees each way, stop-loss, take-profit, leverage, daily limits) and what it does not (slippage, funding), fill timing at candle close, and the fact that the Jev approval gate is bypassed so every candidate buy appears. This is exactly the disclosure an agent needs to interpret results honestly.

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?

Dense, front-loaded, and each sentence carries operational content: engine fidelity, gaps, and return contents. The closing 'past results do not predict future ones' is a familiar disclaimer that earns its place only marginally.

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 carries the burden and does: it names the metrics returned (vs. stake, vs. holding, win rate, worst drop, fees, latest trades with engine reasoning). Combined with the fidelity caveats, an agent can call and interpret this without further information.

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% and the nested rule schema is richly annotated, so the baseline is 3. The description still adds meaning by enumerating which rule fields the simulation actually exercises (fees, stop-loss, take-profit, leverage, daily limits), telling the agent these parameters change results in ways the schema alone does not convey.

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?

States a specific verb and resource: replay a rule over Binance closed-candle history using the live engine's decisions. An agent knows exactly what it does. It does not, however, name the sibling it differs from (test_strategy, check_rule), so it falls short of full sibling differentiation.

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 implied rather than stated: it is a historical simulation with engine-accurate fees/exits, so you use it before going live. The note that the Jev confirm check is skipped here also hints at how this differs from a live run. But there is no explicit 'use this instead of X' routing to test_strategy or check_rule.

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